Historical and Current Perspective in the Use of Thyroid Extracts for the Treatment of Hypothyroidism

Objective: To describe the history, refinements, implementation, physiology, and clinical outcomes achieved over the past several centuries of thyroid hormone replacement strategies.Methods: A Medline search was initiated using the following search terms: bioidentical thyroid hormone, thyroid hormone extract, combination thyroxine (T4) and tri-iodothyronine (T3) therapy, homeopathic thyroid hormone therapy, and thyroid hormone replacement. Pertinent articles of interest were identified by title (and where available abstract) for further review. Additional references were identified during a review of the identified literature.Results: A rich history of physician intervention in thyroid dysfunction was identified dating back more than 2 millennia. Although not precisely documented, thyroid ingestion from animal sources had been used for centuries but was finally scientifically described and documented in Europe over 130 years ago. Since the reports by Bettencourt and Murray, there has been a continuous documentation of outcomes, refinement of hormone preparation production, and updating of recommendations for the most effective and safe use of these hormones for relieving the symptoms of hypothyroidism. As the thyroid extract preparations contain both levothyroxine (LT4) and liothyronine (LT3), current guidelines do not endorse their use as controlled studies do not clearly document enhanced objective outcomes compared with LT4 monotherapy. Among current issues cited, the optimum ratio of LT4 to LT3 has yet to be determined, and the U.S. Food and Drug Administration (FDA) does not appear to be monitoring the thyroid hormone ratios or content in extract preparations on the market. Taken together, these limitations are important detriments to the use of thyroid extract products.Conclusion: The evolution of thyroid hormone therapies has been significant over the extended period of time they have been in use to treat hypothyroidism. Although numerous websites continue to advocate the use of thyroid hormone extracts as a superior therapy for hypothyroidism, none of the most recent guidelines of major endocrine societies recommend thyroid extract use for hypothyroidism.Abbreviations: AACE = American Association of Clinical Endocrinologists ATA = American Thyroid Association BMR = basal metabolic rate FDA = Food and Drug Administration FT4 = free thyroxine 131-I = radioactive iodine 131 LT3 = liothyronine LT4= levothyroxine NDA = new drug application PBI = proteinbound iodine T3 = triiodothyronine T4 = thyroxine TSH = thyroid-stimulating hormone TT3 = total triiodothyronine USP = U.S. Pharmacopeia     

Alterations In Thyroid Hormone Levels Following Growth Hormone Replacement Exert Complex Biological Effects

Objective: Alterations in the thyroid axis are frequently observed following growth hormone (GH) replacement, but uncertainty exists regarding their clinical significance. We aimed to compare fluctuations in circulating thyroid hormone levels, induced by GH, to changes in sensitive biological markers of thyroid hormone action.Methods: This was a prospective observational clinical study. Twenty hypopituitary men were studied before and after GH replacement. Serum thyroid-stimulating hormone (TSH), thyroid hormones, and insulin-like growth factor 1 were measured. Changes in thyroid hormone concentrations were compared to alterations in resting metabolic rate and cardiac time intervals. Health-related quality of life (QOL) was assessed by disease-sensitive and generic questionnaires.Results: Following GH replacement, free thyroxine concentration declined and free triiodothyronine level increased. Resting energy expenditure increased, particularly in subjects with profound hypopituitarism, including TSH deficiency (16.73 ± 1.75 kcal/kg/min vs. 17.96 ± 2.26 kcal/kg/min; P = .01). Alterations in the thyroid axis were more pronounced in subjects with a low/normal baseline respiratory quotient (RQ) who experienced a paradoxical rise in RQ (0.81 vs. 0.86; P = .01). Subjects with a high baseline RQ experienced a slight but nonsignificant fall in RQ without alteration in thyroid axis. The isovolumetric contraction time was shortened during the study; however, this did not reach statistical significance. Improvements in QOL were observed despite alterations in thyroid axis.Conclusion: Changes in the thyroid axis following GH replacement are associated with complex tissue-specific effects. These fluctuations may induce a hypothyroid phenotype in some tissues while appearing to improve the biological action of thyroid hormone in other organs.Abbreviations: AGHDA = Assessment of Growth Hormone Deficiency in Adulthood; CHOox = carbohydrate oxidation; ET = ejection time; fT3 = free triiodothyronine; fT4 = free thyroxine; GH = growth hormone; GHD = growth hormone deficiency; HB-RQ = high baseline respiratory quotient; HPT = hypothalamic-pituitary-thyroid; ICT = isovolumetric contraction time; IGF-1 = insulin-like growth factor 1; IRT = isovolumetric relaxation time; LB-RQ = low baseline respiratory quotient; LV = left ventricular; NHP = Nottingham Health Profile; QOL = quality of life; REE = resting energy expenditure; RQ = respiratory quotient; rT3 = reverse triiodothyronine; SF-36 = Short Form 36; TSH = thyroid-stimulating hormone; T3 = triiodothyronine; T4 = thyroxine; TT3 = total triiodothyronine; TT4 = total thyroxine     

Italian Association of Clinical Endocrinologists Statement–Replacement Therapy for Primary Hypothyroidism: A Brief Guide for Clinical Practice

Objective: Hypothyroidism requires life-long thyroid hormone replacement therapy in most patients. Oral levothyroxine (LT4) is an established safe and effective treatment for hypothyroidism, but some issues remain unsettled.Methods: The Italian Association of Clinical Endocrinologists appointed a panel of experts to provide an updated statement for appropriate use of thyroid hormone formulations for hypothyroidism replacement therapy. The American Association of Clinical Endocrinologists' protocol for standardized production of clinical practice guidelines was followed.Results: LT4 is the first choice in replacement therapy. Thyroid-stimulating hormone (TSH) should be maintained between 1.0 and 3.0 mIU/L in young subjects and at the upper normal limit in elderly or fragile patients. Achievement of biochemical targets, patient well-being, and adherence to treatment should be addressed. In patients with unstable serum TSH, a search for interfering factors and patient compliance is warranted. Liquid or gel formulations may be considered in subjects with hampered LT4 absorption or who do not allow sufficient time before or after meals and LT4 replacement. Replacement therapy with LT4 and L-triiodothyronine (LT3) combination is generally not recommended. A trial may be considered in patients with normal values of serum TSH who continue to complain of symptoms of hypothyroidism only after co-existent nonthyroid problems have been excluded or optimally managed. LT3 should be administered in small (LT4:LT3 ratio, 10:1 to 20:1) divided daily doses. Combined therapy should be avoided in elderly patients or those with cardiac risk factors and in pregnancy.Conclusion: LT4 therapy should be aimed at resolution of symptoms of hypothyroidism, normalization of serum TSH, and improvement of quality of life. In selected cases, the use of liquid LT4 formulations or combined LT4/LT3 treatment may be considered to improve adherence to treatment or patient well-being.Abbreviations:AACE = American Association of Clinical EndocrinologistsFT3 = free triiodothyronineFT4 = free thyroxineLT3 = levotriiodothyronineLT4 = levothyroxineMeSH = medicine medical subject headingsQoL = quality of lifeTSH = thyroid-stimulating hormone     

Hormone Substitution after Gastric Bypass Surgery in Patients with Hypopituitarism Secondary to Craniopharyngioma

Objective: Craniopharyngiomas (CPs) are benign brain tumors presenting frequently in childhood and are treated by surgery with or without radiotherapy. About 50% of cured patients suffer from eating disorders and obesity due to hypothalamic damage, as well as hypopituitarism, necessitating subsequent hormone substitution therapy. Gastric bypass surgery has been reported to be an efficient treatment strategy for morbid hypothalamic obesity. However, so far it is unknown whether oral hormone substitution is affected by impaired intestinal drug absorption, potentially leading to severe hypopituitarism or pituitary crisis.Methods: Four morbidly obese CP patients with panhypopituitarism treated by gastric bypass surgery were included in this retrospective analysis. Dosages of hormone substitution therapy, blood concentrations of hormones, potential complications of impaired drug absorption, and anthropometric characteristics were investigated pre- and postoperatively after 6 to 14 months and 13 to 65 months.Results: In all CP patients (3 female/1 male; baseline body mass index, 49 ± 7 kg/m²), gastric bypass resulted in distinct weight loss (-35 ± 27 kg). In follow-up examinations, mean daily dosage of thyroid hormone (levothyroxine_baseline 156 ± 44 μg/day versus levothyroxine_follow-up 150 ± 30 μg/day), hydrocortisone (hydrocortisone_baseline 29 ± 12 mg/day versus hydrocortisone_follow-up 26 ± 2 mg/day), growth-hormone (somatotropin_baseline 0.9 ± 0.5 mg/day versus somatotropin_follow-up 1.0 ± 0.4 mg/day), and desmopressin (desmopressin_baseline 222 ± 96 μg/day versus desmopressin_follow-up 222 ± 96 μg/day) substitution was unchanged. No patient developed adrenal insufficiency. Oral thyroid/hydrocortisone absorption testing performed in 1 patient indicated sufficient gastrointestinal drug absorption after bariatric surgery.Conclusion: Our preliminary results suggest that oral hormone substitution therapy is not impaired following gastric bypass operation in CP patients with morbid obesity, indicating that it might be a safe and effective treatment strategy.Abbreviations:BMI = body mass indexCP = craniopharyngiomafT4 = free thyroxineGH = growth hormoneIGF-1 = insulin-like growth factor 1     

Trends In Growth Hormone Stimulation Testing And Growth Hormone Dosing In Adult Growth Hormone Deficiency Patients: Results From The Answer Program

Objective: Adult growth hormone deficiency (AGHD) results in physiologic impairments that may reduce quality of life and negatively impact body composition. AGHD can be treated with recombinant human growth hormone (GH). This study analyzes AGHD patients enrolled in the American Norditropin® Studies: Web-Enabled-Research (ANSWER) Program/NovoNet, a U.S. observational noninterventional study of patients treated with Norditropin® (somatropin [recombinant DNA origin] injection) at the discretion of their physicians.Methods: Data were evaluated for GH stimulation test (GHST) usage and Norditropin® doses over 4 years.Results: Adults (N = 468) with isolated GHD (IGHD) or multiple pituitary hormone deficiency (MPHD) were evaluated. The most commonly used GHSTs were arginine + L-dopa (27%; mostly a single center) and glucagon (25%; most frequent test after 2009). The percent of patients meeting recommended test-specific cut points varied from 32 to 100%, depending on the GHST used. Mean baseline GH doses were higher for MPHD patients and for younger patients in both IGHD and MPHD groups.Conclusion: MPHD was more common than IGHD. Mean GH doses were higher in younger patients, consistent with a transition from higher pediatric to lower adult dosing. Over time, glucagon became the most popular GHST. The use, in some patients, of other GHSTs with cut points, as well as starting doses not consistent with current recommendations, highlights the need for continued education regarding treatment guidelines for AGHD.Abbreviations:AACE = American Association of Clinical EndocrinologistsAGHD = adult growth hormone deficiencyANSWER = American Norditropin® Studies: Web-Enabled-ResearchBMI = body mass indexGH = growth hormoneGHD = growth hormone deficiencyGHRH = growth hormone-releasing hormoneGHST = growth hormone stimulation testIGF-1 = insulin-like growth factor-1IGHD = isolated growth hormone deficiencyITT = insulin tolerance testKIMS = Pfizer International Metabolic DatabaseMPHD = multiple pituitary hormone deficiencyTES = The Endocrine Society     

Plurihormonal Pituitary Adenoma Immunoreactive for Thyroid-Stimulating Hormone,Growth Hormone,Follicle-Stimulating Hormone,and Prolactin

ObjectiveTo describe the case of a patient with an unusual plurihormonal pituitary adenoma with immunoreactivity for thyroid-stimulating hormone (TSH), growth hormone, follicle-stimulating hormone, prolactin, an α-subunit.MethodsWe report the clinical, laboratory, imaging, and pathology findings of a patient symptomatic from a plurihormonal pituitary adenoma and describe her outcome after surgical treatment.ResultsA 60-year-old woman presented to the emergency department with headaches, blurry vision, fatigue, palpitations, sweaty hands, and weight loss. Her medical history was notable for hyperthyroidism, treated intermit with methimazole. Magnetic resonance imaging disclosed a pituitary macroadenoma (2.3 by 2.2 by 2.0 cm), and preoperative blood studies revealed elevated levels of TSH at 6.11 mIU/L, free thyroxine at 3.6 ng/dL, and free triiodothyronine at 6.0 pg/mL. She underwent an uncomplicated transsphenoidal resection of the pituitary adenoma. Immunostaining of tumor tissue demonstrated positivity for not only TSH but also growth hormone, follicle-stimulating hormone, prolactin, and α-subunit. The Ki-67 index of the tumor was estimated at 2% to 5%, and DNA repair enzyme O6-methylguanine-DNA methyltransferase immunostaining was mostly negative. Electron microscopy showed the ultrastructural phenotype of a glycoprotein-producing adenoma. Postoperatively, her symptoms and hyperthyroidism resolved.ConclusionThyrotropin-secreting pituitary adenomas are rare. Furthermore, recent reports suggest that 31% to 36% of adenomas may show evidence of secretion of multiple pituitary hormones. This case emphasizes the importance of considering pituitary causes of thyrotoxicosis and summarizes the clinical and pathology findings in a patient with a plurihormonal pituitary adenoma. (Endocr Pract. 2012;18:e121-e126)     

Lingual Thyroid: 35-Year Experience At A Tertiary Care Referral Center

Objective: Lingual thyroid (LT) results from a developmental abnormality due to failure of the thyroid gland to descend to its pretracheal position. Given the low incidence of this disease, standardized management recommendations are lacking. We aimed to describe our institution's experience in LT management and to suggest a practice algorithm.Methods: We conducted a retrospective review of LT diagnosed at Mayo Clinic, Rochester, Minnesota, between1976 and 2010. Demographics, clinical presentation, laboratory data, treatment received, and outcomes were collected.Results: We identified 29 patients with LT. Eighty-three percent were female; age at diagnosis ranged from 2 weeks to 68 years. Almost one-third of patients were symptomatic, with the most common symptoms being cough and hoarseness. The diagnosis of LT was incidental in 9 patients (31%). Seventy-two percent of patients developed hypothyroidism. Levothyroxine was the treatment of choice, followed by thyroidectomy. Two asymptomatic euthyroid patients were followed without any intervention.Conclusion: Management of patients with LT should be individualized and guided by the patient's symptoms and thyroid hormone status.Abbreviations:LT = lingual thyroidRAI = radioactive iodine     

American Association of Clinical Endocrinologists and American College of Endocrinology Guidelines for Management of Growth Hormone Deficiency in Adults and Patients Transitioning from Pediatric to Adult Care

Objective: The development of these guidelines is sponsored by the American Association of Clinical Endocrinologists (AACE) Board of Directors and American College of Endocrinology (ACE) Board of Trustees and adheres with published AACE protocols for the standardized production of clinical practice guidelines (CPG).Methods: Recommendations are based on diligent reviews of clinical evidence with transparent incorporation of subjective factors, according to established AACE/ACE guidelines for guidelines protocols.Results: The Executive Summary of this 2019 updated guideline contains 58 numbered recommendations: 12 are Grade A (21%), 19 are Grade B (33%), 21 are Grade C (36%), and 6 are Grade D (10%). These detailed, evidence-based recommendations allow for nuance-based clinical decision-making that addresses multiple aspects of real-world care of patients. The evidence base presented in the subsequent Appendix provides relevant supporting information for the Executive Summary recommendations. This update contains 357 citations of which 51 (14%) are evidence level (EL) 1 (strong), 168 (47%) are EL 2 (intermediate), 61 (17%) are EL 3 (weak), and 77 (22%) are EL 4 (no clinical evidence).Conclusion: This CPG is a practical tool that practicing endocrinologists and regulatory bodies can refer to regarding the identification, diagnosis, and treatment of adults and patients transitioning from pediatric to adult-care services with growth hormone deficiency (GHD). It provides guidelines on assessment, screening, diagnostic testing, and treatment recommendations for a range of individuals with various causes of adult GHD. The recommendations emphasize the importance of considering testing patients with a reasonable level of clinical suspicion of GHD using appropriate growth hormone (GH) cut-points for various GH–stimulation tests to accurately diagnose adult GHD, and to exercise caution interpreting serum GH and insulin-like growth factor-1 (IGF-1) levels, as various GH and IGF-1 assays are used to support treatment decisions. The intention to treat often requires sound clinical judgment and careful assessment of the benefits and risks specific to each individual patient. Unapproved uses of GH, long-term safety, and the current status of long-acting GH preparations are also discussed in this document.LAY ABSTRACTThis updated guideline provides evidence-based recommendations regarding the identification, screening, assessment, diagnosis, and treatment for a range of individuals with various causes of adult growth-hormone deficiency (GHD) and patients with childhood-onset GHD transitioning to adult care. The update summarizes the most current knowledge about the accuracy of available GH–stimulation tests, safety of recombinant human GH (rhGH) replacement, unapproved uses of rhGH related to sports and aging, and new developments such as long-acting GH preparations that use a variety of technologies to prolong GH action. Recommendations offer a framework for physicians to manage patients with GHD effectively during transition to adult care and adulthood. Establishing a correct diagnosis is essential before consideration of replacement therapy with rhGH. Since the diagnosis of GHD in adults can be challenging, GH–stimulation tests are recommended based on individual patient circumstances and use of appropriate GH cut-points. Available GH–stimulation tests are discussed regarding variability, accuracy, reproducibility, safety, and contraindications, among other factors. The regimen for starting and maintaining rhGH treatment now uses individualized dose adjustments, which has improved effectiveness and reduced reported side effects, dependent on age, gender, body mass index, and various other individual characteristics. With careful dosing of rhGH replacement, many features of adult GHD are reversible and side effects of therapy can be minimized. Scientific studies have consistently shown rhGH therapy to be beneficial for adults with GHD, including improvements in body composition and quality of life, and have demonstrated the safety of short- and long-term rhGH replacement.Abbreviations: AACE = American Association of Clinical Endocrinologists; ACE = American College of Endocrinology; AHSG = alpha-2-HS-glycoprotein; AO-GHD = adult-onset growth hormone deficiency; ARG = arginine; BEL = best evidence level; BMD = bone mineral density; BMI = body mass index; CI = confidence interval; CO-GHD = childhood-onset growth hormone deficiency; CPG = clinical practice guideline; CRP = C-reactive protein; DM = diabetes mellitus; DXA = dual-energy X-ray absorptiometry; EL = evidence level; FDA = Food and Drug Administration; FD-GST = fixed-dose glucagon stimulation test; GeNeSIS = Genetics and Neuroendocrinology of Short Stature International Study; GH = growth hormone; GHD = growth hormone deficiency; GHRH = growth hormone–releasing hormone; GST = glucagon stimulation test; HDL = high-density lipoprotein; HypoCCS = Hypopituitary Control and Complications Study; IGF-1 = insulin-like growth factor-1; IGFBP = insulin-like growth factor–binding protein; IGHD = isolated growth hormone deficiency; ITT = insulin tolerance test; KIMS = Kabi International Metabolic Surveillance; LAGH = long-acting growth hormone; LDL = low-density lipoprotein; LIF = leukemia inhibitory factor; MPHD = multiple pituitary hormone deficiencies; MRI = magnetic resonance imaging; P-III-NP = procollagen type-III amino-terminal pro-peptide; PHD = pituitary hormone deficiencies; QoL = quality of life; rhGH = recombinant human growth hormone; ROC = receiver operating characteristic; RR = relative risk; SAH = subarachnoid hemorrhage; SDS = standard deviation score; SIR = standardized incidence ratio; SN = secondary neoplasms; T3 = triiodothyronine; TBI = traumatic brain injury; VDBP = vitamin D-binding protein; WADA = World Anti-Doping Agency; WB-GST = weight-based glucagon stimulation test     

Metabolic Effects Of Hormone Therapy In Transgender Patients

Objective: Transgender patients may seek hormone therapy to induce physical changes to simulate their expressed or experienced gender. However, many providers are uncomfortable prescribing transgender hormones due to fears over safety. The goal of this study was to determine if transgender hormone therapy with estrogen and spironolactone for male-to-female (MtF) patients or with testosterone for female-to-male (FtM) patients had adverse anthropomorphic or metabolic effects.Methods: This retrospective chart review study analyzed changes over time for 33 MtF and 19 FtM endocrine clinic patients at an academic endocrine practice with follow-up for up to 18 months after hormone initiation.Results: Compared to baseline labs obtained prior to the initiation of hormone therapy, significant changes for the MtF cohort included an increase in high-density lipoprotein (HDL) and decrease in creatinine; however, triglycerides did not show a statistically significant change. In the FtM cohort, there were significant increases in body mass index, creatinine, hemoglobin, and hematocrit. Although statistically significant, these changes were minimal for both cohorts.Conclusion: In our practice, hormone therapy was found to be safe in this retrospective study.Abbreviations:BMI = body mass indexFtM = female-to-maleHDL = high-density lipoproteinLDL = low-density lipoproteinMtF = male-to-female     

Correlation of Increased Serum Adipsin with Increased Cardiovascular Risks in Adult Patients with Growth Hormone Deficiency

Objective: Adult growth hormone deficiency (AGHD) patients have an increased cardiovascular morbidity and mortality. Adipsin is an adipokine that is significantly correlated with metabolic disease, especially in people with obesity. The objective of our study was to compare AGHD patients with healthy subjects to evaluate whether adipsin levels are closely related to glycolipid metabolism and cardiovascular risks in AGHD patients.Methods: Our study included 88 AGHD patients and 88 age-, weight-, and body mass index (BMI)-matched healthy subjects. Anthropometric parameters such as BMI, waist circumference, and blood pressure were measured. Biochemical indicators such as serum adipsin, lipids, and fasting insulin levels were determined.Results: Adipsin levels in AGHD patients were significantly increased compared to levels of the control group (11,567.29 ng/mL, interquartile &lsqb;9,856.46 to 13,360.60 ng/mL]) versus (9,127.86 ng/mL, interquartile &lsqb;8,061.82 to 10,647.06 ng/mL], P = .000). Increased serum adipsin levels are correlated with cardiovascular risk factors such as a higher waist-to-hip ratio, serum lipids levels, and insulin resistance. Adipsin levels were inversely related to insulin-like growth factor 1 (IGF-1) (r = -0.6363, P<.0001) and insulin-like growth factor binding protein 3 levels (r = -0.498, P<.0001). The odds ratio (OR) for AGHD in the highest quartile was found to be 4.491 times the ratio in the lowest quartile (OR = 4.491, P = .048). Additionally, adipsin was found to be the most independent factor to influence IGF-1 levels in AGHD subjects.Conclusion: The serum levels of adipsin were significantly correlated with glucolipid metabolism disorder with a growth hormone deficiency status. Furthermore, serum levels of adipsin might be a good marker for the occurrence and development of cardiovascular diseases in AGHD patients.Abbreviations: AGHD = adult growth hormone deficiency; ASCVD = atherosclerotic cardiovascular disease; BMI = body mass index; DBP = diastolic blood pressure; FINS = fasting insulin; FPG = fasting plasma glucose; GH = growth hormone; HOMA-IR = homeostatic model to assess insulin resistance index; hsCRP = high-sensitivity C-reactive protein; IGF-1 = insulin-like growth factor 1; IGFBP-3 = insulin-like growth factor binding protein 3; LAP = lipid accumulation products; LDL = low-density lipoprotein; SBP = systolic blood pressure; TC = total cholesterol; TG = triglycerides; WC = waist circumference; WHR = waist-to-hip ratio; OR = odds ratio     

Mifepristone Treatment for Mild Autonomous Cortisol Secretion Due to Adrenal Adenomas: A Pilot Study

Objective: Adrenal incidentalomas are increasingly detected with the widespread use of thoracic and abdominal imaging. The most common secretory syndrome in adrenal nodules is autonomous cortisol secretion (ACS). Recent data show that even mild cortisol excess is associated with adverse outcomes. The glucocorticoid receptor antagonist mifepristone has been used in patients with overt Cushing syndrome and hyperglycemia. The purpose of our study was to determine the effect of mifepristone on metabolic parameters in patients with ACS and concomitant prediabetes or diabetes.Methods: Eight patients with either unilateral or bilateral adrenal nodules with ACS were included in the study. Fasting laboratory tests including glucose and insulin levels to calculate homeostatic model assessment for insulin resistance (HOMA-IR) were performed at baseline and again after either 3 months (3 patients) or 6 months (5 patients) on mifepristone 300 mg daily treatment. Patients also completed several validated surveys on mood and quality of life at baseline and follow-up.Results: There were significant reductions in fasting glucose measurements and insulin resistance as measured by HOMA-IR in the 6 of 8 study patients in whom these measurements were available (P = .03).Conclusion: This pilot study demonstrates that mifepristone treatment of ACS is associated with a significant decrease in fasting glucose and insulin resistance as measured by HOMA-IR scores. Mifepristone treatment of ACS may be considered as a medical option for patients with ACS due to adrenal adenomas with concomitant abnormal glucose parameters in whom surgical removal is not being considered.Abbreviations: ACS = autonomous cortisol secretion; ACTH = adrenocorticotropic hormone; AI = adrenal incidentaloma; DHEAS = dehydroepiandrosterone sulfate; GR = glucocorticoid receptor; HbA1c = hemoglobin A1c; HOMA-IR = homeostatic model assessment for insulin resistance; ODT = overnight dexamethasone suppression test; QoL = quality of life; STAI = state trait anxiety inventory; TSH = thyroid stimulating hormone; UFC = urinary free cortisol     

Latent Adrenal Insufficiency: Concept,Clues to Detection,and Diagnosis

In 1855, Thomas Addison described an illness now known as Addison disease (AD) caused by damage to the adrenal cortex and manifesting in weakness, weight loss, hypotension, gastrointestinal disturbances, and brownish pigmentation of the skin and mucous membranes. Corticosteroid supplementation, corticotropin (adrenocorticotropic hormone [ACTH] of medicinal use) test, and anti-adrenal auto-antibodies (AA) have come into use in the 100 years since Addison's death. Following the methodological innovations, 4 disorders which share impaired response to corticotropin in common have been discovered (i.e., partial AD, apigmented adrenal insufficiency [AI], subclinical AI, and the AA-positive state exclusively in subjects proven to have an impaired response to corticotropin). As they are hidden, potentially serious conditions, these disorders are bound together as latent AI (LAI). Diagnosis of AD is often delayed, which may lead to adrenal crisis. If LAI were widely recognized, such delays would not exist and crises would be averted. The 3 existing guidelines do not refer much to LAI patients outside those in acute situations. To address this, information relevant to clinical manifestations and diagnostic tests of LAI was sought in the literature. Signs and symptoms that are useful clues to begin a diagnostic workup are presented for endocrinologists to identify patients with suspected LAI. The utility of 2 corticotropin test protocols is reviewed. To endorse LAI shown by the corticotropin test, monitoring items following corticosteroid supplementation are cited from the guidelines and supplemented with the author's observations.Abbreviations: AA = anti-adrenal auto-antibodies; Ab = antibodies; ACA = AA detected by immunofluorescence; ACTH = adrenocorticotropic hormone; AD = Addison disease; AI = adrenal insufficiency; DHEA = dehydroepiandrosterone; GC = glucocorticoid; IFA = immunofluorescence assay; LAI = latent AI; LDT = low-dose test; MC = mineralocorticoid; 21OHAb = anti-21-hydroxylase Ab; ST = standard test; URI = upper respiratory infection     

No Benefit of Dedicated Thyroid Nodule Screening in Patients with Acromegaly

Objective: Acromegaly results from the excessive production of growth hormone and insulin-like growth factor-1. While there is up to a 2-fold increased prevalence of thyroid nodules in patients with acromegaly, the incidence of thyroid cancer in this population varies from 1.6 to 10.6% in several European studies. The goal of our study was to determine the prevalence of thyroid nodules and thyroid cancer among patients with acromegaly at a large urban academic medical center in the United States (U.S.).Methods: A retrospective chart review was performed of all patients with acromegaly between 2006–2015 within the University of California, Los Angeles health system. Data were collected regarding patient demographics, thyroid ultrasounds, thyroid nodule fine needle aspiration (FNA) biopsy cytology, and thyroid surgical pathology.Results: In this cohort (n = 221, 49.3% women, mean age 53.8 ± 15.2 &lsqb;SD] years, 55.2% Caucasian), 102 patients (46.2%) underwent a thyroid ultrasound, from which 71 patients (52.1% women, mean age 52.9 ± 15.2 &lsqb;SD] years, 56.3% Caucasian) were found to have a thyroid nodule. Seventeen patients underwent a thyroid nodule FNA biopsy and the results revealed 12 benign biopsies, 1 follicular neoplasm, 3 suspicious for malignancy, and 1 papillary thyroid cancer (PTC), from which 6 underwent thyroidectomy; PTC was confirmed by surgical pathology for all cases (8.5% of all nodules observed).Conclusion: In this sample, the prevalence of thyroid cancer in patients with acromegaly and coexisting thyroid nodules is similar to that reported in the general U.S. population with thyroid nodules (7 to 15%). These findings suggest that there is no benefit of dedicated thyroid nodule screening in patients newly diagnosed with acromegaly.Abbreviations: AACE = American Association of Clinical Endocrinologists; ATA = American Thyroid Association; DTC = differentiated thyroid cancer; FNA = fine needle aspiration; GH = growth hormone; IGF-1 = insulin-like growth factor-1; PTC = papillary thyroid cancer; U.S. = United States     

Regulation of Resistin by Gonadal,Thyroid Hormone,and Nutritional Status

Objective: Resistin was recently identified as a hormone secreted by adipocytes that is under hormonal and nutritional control. This hormone has been suggested to be the link between obesity and type 2 diabetes. The aim of this study was to assess the influence of gender, gonadal status, thyroid hormones, pregnancy, and food restriction on resistin mRNA levels in adipose tissue of rats. Research Methods and Procedures: We have determined resistin mRNA expression by Northern blot analysis in all experimental sets. Results: Resistin mRNA expression is influenced by age, with the highest hormone levels existing at 45 days after birth and decreasing thereafter. Resistin mRNA expression is higher in men than in women. Moreover, we studied the effect of orchidectomy and ovariectomy in rats of different ages and showed that gonadal hormones increase adipose tissue resistin mRNA expression in male rats. Resistin is also regulated by thyroid hormones; it is severely decreased in hyperthyroid rats. Our results clearly show that chronic food restriction (30% of ad libitum food intake) led to a decrease in adipose tissue mRNA levels in normal cycling female rats and pregnant rats. In pregnancy, resistin mRNA levels were enhanced particularly at midgestation. Discussion: Our observations indicate that resistin is influenced by gender, gonadal status, thyroid hormones, and pregnancy. These findings suggest that resistin could explain the decreased insulin sensitivity during puberty and could be the link between sex steroids and insulin sensitivity. Moreover, resistin could mediate the effect of thyroid hormones on insulin resistance and the state of insulin resistance present during pregnancy.     

Renal Function and Plasma Renin activity as Potential Factors Causing Hyperkalemia in Patients with Thyroid Carcinoma Undergoing Thyroid Hormone Withdrawal For Radioactive Iodine Therapy

Objective: Hypothyroidism is not commonly considered a cause of hyperkalemia. We previously reported that hyperkalemia was observed mainly in elderly patients treated with renin-angiotensin-aldosterone system (RAS) inhibitors when levothyroxine treatment was withdrawn for the thyroidectomized patients with thyroid carcinoma to undergo radioactive iodine treatment. Here, we investigated whether acute hypothyroidism causes hyperkalemia in patients who were not treated with RAS inhibitors. We also investigated factors influencing potassium metabolism in hypothyroid patients.Methods: We conducted a single-center, prospective cohort study of 46 Japanese patients with thyroid carcinoma undergoing levothyroxine withdrawal prior to radioiodine therapy. All patients were normokalemic before levothyroxine withdrawal. Blood samples were analyzed 3 times: before, and at 3 and 4 weeks after levothyroxine withdrawal. We investigated factors that may be associated with the elevation of serum potassium levels from a euthyroid state to a hypothyroid state.Results: None of the patients developed symptomatic hyperkalemia. The mean serum potassium level was significantly higher at 4 weeks after levothyroxine withdrawal compared to baseline. The serum sodium levels, the estimated glomerular filtration rate (eGFR), and the plasma renin activity (PRA) decreased significantly as hypothyroidism advanced. In contrast, the plasma levels of adrenocorticotropic hormone, cortisol, aldosterone, and antidiuretic hormone were not changed, while serum thyroid hormone decreased. At 4 weeks after their levothyroxine withdrawal, the patients' serum potassium values were significantly correlated with the eGFR and the PRA.Conclusion: Acute hypothyroidism can cause a significant increase in the serum potassium level, which may be associated with a decreased eGFR and decreased circulating RAS.Abbreviations: ACTH = adrenocorticotropic hormone; ADH = antidiuretic hormone; ATPase = adenosine triphosphatase; eGFR = estimated glomerular filtration rate; HbA1c = glycated hemoglobin; K⁺ = potassium; Na⁺ = sodium; PRA = plasma renin activity; RAS = renin-angiotensin-aldosterone system; T4 = thyroxine; TSH = thyroid-stimulating hormone     

Reproducible and Rapid Methods for the Isolation and Assay of a-Factor, a Yeast Mating Hormone

The Saccharomyces cerevisiae mating hormone a-factor has been difficult to isolate reproducibly in sufficient yields by methods using ion-exchange chromatography, probably because of its pronounced hydrophobicity. In this work, a hydrophobic adsorbent (Amberlite XAD-2), in an insoluble bead from, was used to isolate larger (up to sixfold greater than previous reports) and quite reproducible (12% standard deviation) quantities of a-factor by adsorption from cell-free filtrates of a cultures. Moreover, when the beads were added to the cultures at the time of inoculation, sixfold greater yields were obtained than when a-factor was adsorbed to the beads from cell-free filtrates. a-Factor was readily eluted from the beads with 1-propanol. The same adsorbent could also be used in the partial purification of the less hydrophobic α-factor. Adsorption of both hormones by Amberlite XAD-2 gave a degree of purification comparable to that obtained by the first steps of previously published methods while providing larger yields of hormones. The present procedure is shorter, simpler, and, for a-factor, more reproducible. The activities of both hormones were quantitated by using an assay in which the size distribution of cells in the population was monitored after the addition of hormone of the opposite mating type. The extent of increase in cell size which accompanies hormone treatment is a function of the hormone concentration. To ensure solubilization of a-factor in the aqueous bioassay system, samples were diluted into bovine serum albumin solutions and sonicated before assaying. The resulting assay is most sensitive at hormone concentrations between 0.05 and 2 U/ml, can reliably detect as little as 0.16 ng of hormone, gave results reproducible within 16%, and is convenient for a large number (>100) of samples.     

Bird's-Eye View of GnRH Analog use in a Pediatric Endocrinology Referral Center

Objective: Gonadotropin-releasing hormone analogs (GnRHa) are standard of care for the treatment of central precocious puberty (CPP). GnRHa have also been prescribed in other clinical settings with the hope of increasing adult stature, although evidence to support this practice is lacking. The degree to which GnRHa are being prescribed for indications other than CPP in routine clinical care has not been described. We sought to systematically examine GnRHa prescribing practices among the pediatric endocrinologists at our academic medical center.Methods: We reviewed medical records of children treated with GnRHa during a 6-year interval. Variables analyzed included gender, age at start of treatment, indication for therapy, and use of growth hormone as adjunctive treatment. Nonparametric analyses were utilized to compare treatment characteristics of those with CPP versus those without.Results: A total of 260 patients (82% female) aged 8.06 ± 2.68 years were identified. Of these, 191 (73.5%) were treated for CPP, whereas 69 (26.5%) were treated for normally timed puberty in the context of idiopathic short stature/poor predicted height (n = 37), growth hormone deficiency (n = 17), congenital adrenal hyperplasia (n = 10), primary hypothyroidism (n = 4), and developmental delay (n = 1). Of the 161 girls with CPP, GnRHa therapy was initiated at =8 years of age in 62 (39%).Conclusion: Whereas most patients were treated for CPP, ~27% were treated for other indications. Of girls with CPP, 39% were treated at an age when benefit in terms of height is unlikely. This highlights the need for rigorous studies of GnRHa use for indications beyond CPP.Abbreviations: CPP = central precocious puberty GnRHa = gonadotropin-releasing hormone analogs     

Understanding Worry About Risks Associated With Thyroid Hormone Therapy: A National Survey of Endocrinologists,Family Physicians,and Geriatricians

ObjectiveThyroid hormone use is widespread, and prior studies have shown that over- and undertreatment with thyroid hormone are common. Our objective was to understand physician worry regarding risks associated with thyroid hormone therapy, specifically overtreatment or undertreatment.MethodsA nationwide survey was administered to physician members of the Endocrine Society, the American Academy of Family Practice, and the American Geriatrics Society. Participants were asked how often they were worried about various risks that may be associated with thyroid hormone over- or undertreatment, that is, cardiovascular complications, bone complications, and poor quality of life due to overtreatment or undertreatment with thyroid hormone. Multivariable regression analyses were conducted to determine physician characteristics associated with each worry.ResultsThe response rate was 63% (359 of 566); of those who responded, 128 (36%) were primary care physicians, 114 (32%) were endocrinologists, and 113 (32%) were geriatricians. Overall, 74 (21%) physicians reported that they frequently or always worried about cardiovascular complications, 74 (21%) about bone complications, 111 (31%) about the poor quality of life due to symptoms from undertreatment with thyroid hormone, and 87 (24%) about the poor quality of life due to symptoms from overtreatment with thyroid hormone. Endocrinologists were more likely to frequently or always worry about the patients' poor quality of life due to symptoms from overtreatment (odds ratio, 2.05; 95% confidence interval, 1.09-3.93) compared with primary care physicians.ConclusionUp to one third of the physicians frequently or always worried about risks resulting from the thyroid hormone overtreatment or undertreatment. More research is needed across specialties to understand physician perceptions of how thyroid hormone therapy impacts the patients' quality of life.     

Optimal Management of Hypothyroidism: Incremental Improvements for use in 2016 and Beyond

Abbreviations:FT3 = free T3FT4 = free T4LT3 = tri-iodothyronineLT4 = levothyroxineTSH = thyroid-stimulating hormone     

Lymphocytic Thyroiditis is Associated with Increased Number of Benign Cervical Nodes and Fewer Central Neck Compartment Metastatic Lymph Nodes in Patients with Differentiated Thyroid Cancer

Objective: Whether or not autoimmune thyroid disease influences the progression of differentiated thyroid cancer (DTC) remains controversial. Findings of previous studies are influenced by lead time bias and/or procedure bias selection. These biases can be reduced by studying a single-institution patient population that underwent a similar extent of surgical resection.Methods: From a cohort of 660 patients with DTC who underwent thyroidectomy, we retrospectively studied 357 patients who underwent total thyroidectomy and central compartment node dissection (CCND) for DTC between 2003 and 2013.Results: Forty-one percent (140/345) of study patients had lymphocytic thyroiditis (LT), and 30% (91/301) had serum positive for thyroglobulin antibody (TgAb). LT was reported in 78% of the TgAb-positive cases. Sixty percent (213/357) of cases had metastatic thyroid carcinoma in 1 or more neck lymph nodes (55% [198/357] central compartment, and 22% [77/356] lateral compartment). Patients with LT had fewer metastatic cervical lymph nodes than those with no LT (2.7 ± 4.7 vs 3.5 ± 4.8, respectively, P = .0285). Patients with positive TgAb and thyroiditis had a larger number of benign cervical lymph nodes removed than those with negative TgAb or no LT. No significant difference was observed in age, tumor size, multifocality, extrathyroidal extension, vascular invasion, or frequency of cervical lymph node metastasis between TgAb-negative and -positive cases or between cases with and without LT.Conclusion: Lymphocytic thyroiditis is associated with fewer central neck compartment metastatic lymph nodes and a larger number of excised reactive benign cervical lymph nodes. Whether this association indicates a protective role of thyroid autoimmunity in lymph node spreading remains unclear.Abbreviations:CCND = central compartment node dissectionDTC = differentiated thyroid cancerHT = Hashimoto thyroiditisLT = lymphocytic thyroiditisTgAb = thyroglobulin antibodyTPO = thyroid peroxidase