Comparison of Effects of Long-term Corticotrophin and Corticosteroid Treatment on Responses of Plasma Growth Hormone,ACTH, and Corticosteroid to Hypoglycaemia

The development of the highly sensitive cytochemical bioassay for ACTH has permitted the measurement of plasma ACTH levels during the insulin hypoglycaemia test (I.H.T.) in patients treated with corticosteroids and corticotrophin. The ACTH, corticosteroid, and growth hormone (GH) responses in the I.H.T. were measured in three groups of 12 rheumatoid arthritis patients. One group was receiving long-term corticotrophin treatment, the second was undergoing long-term corticosteroid treatment, and the third had never received systemic hormone therapy. The increments in plasma ACTH, corticosteroids, and GH were diminished in the corticosteroid-treated group, as were increments in plasma GH and ACTH in the corticotrophin-treated group; but in this group the corticosteroid increment was normal. Examination of the area under the curve of the ACTH response showed that the total amount of ACTH secreted was normal though the rate of secretion was reduced. In the corticosteroid-treated group both rate and total secretion were diminished.     

Immunoreactive Corticotrophin Levels in Adrenocortical Insufficiency

Plasma concentrations of immunoreactive corticotrophin (ACTH) have been determined in 14 patients with untreated Addison''s disease and in 42 patients with secondary adrenocortical insufficiency. Basal morning plasma ACTH levels were markedly raised in those with Addison''s disease but were either in the normal range or undetectable in the group with secondary adrenocortical insufficiency. In the group with Addison''s disease circulating ACTH values showed a definite nyctohemeral rhythm, a pronounced rise in response to insulin-induced hypoglycaemia, and an immediate fall following the intravenous injection of corticosteroids, with a half-life of between 13·5 and 44·2 minutes. When assays were performed with antisera directed against the portion of the ACTH molecule responsible for corticosteroidogenesis (the N-terminal portion) the apparent ACTH concentrations were lower than with antisera directed against the non-steroidogenic (C-terminal) portion of the molecule. This emphasizes that different antisera may give different apparent hormone concentrations, and that the ranges of values obtained in normal and abnormal states must be established for each antiserum.     

Plasma corticotrophin levels in addison-schilder's disease.

Raised plasma immunoreactive corticotrophin (ACTH) levels were found in five boys with the sex-linked disorder progressive leucodystrophy associated with adrenal insufficiency (Addison-Schilder''s disease) and in a symptom-free brother of one of them. Similar ACTH concentrations were found using two antisera, one against the N-terminal part of the ACTH molecule and the other against the C-terminal part. In one patient the circulating ACTH had normal biological activity as measured using the cytochemical ACTH bioassay. Immunoreactive beta/-melanocyte-stimulating hormone was also determined in one patient and found to be raised.     

Cortisol and Growth Hormone Secretion in Relation to Linear Growth: Patients with Still's Disease on Different Therapeutic Regimens

Linear growth was studied in 20 children suffering from Still''s disease on various treatment regimens, and their ability to secrete growth hormone and cortisol was investigated. Growth recovered on reducing daily corticosteroid therapy or on changing to an alternative regimen. Retardation of growth was not due to an absolute inability to secrete growth hormone. Basal plasma cortisol levels and the plasma cortisol response to hypoglycaemia were reduced in patients on daily steroid therapy, but patients on alternate-day prednisone did not differ significantly in this respect from those on non-steroid regimens. Those on alternate-day corticotrophin showed preservation of the circadian rhythm but a subnormal response to hypoglycaemia.     

Lactation‐associated infertility in Japanese monkeys (Macaca fuscata) during the breeding season

To investigate the endocrine factors in Japanese monkeys (Macaca fuscata) responsible for the suppression of the estrous cycle during the first reproductive season after delivery (150–360 days postpartum), peripheral blood was taken to measure plasma concentrations of follicle stimulating hormone (FSH), luteinizing hormone (LH), progesterone, estradiol‐17β, immunoreactive (ir)‐inhibin, and cortisol. The results demonstrated that during the breeding season of lactating Japanese monkeys, circulating concentrations of FSH (1.7–2.7 ng/ml), LH (308.5–461.0 pg/ml), estradiol‐17β (<62.6 pg/ml), and progesterone (145.0–453.0 pg/ml) remained low and were similar to the nadir levels observed during both the normal menstrual cycles and the nonbreeding season. Concentrations of ir‐inhibin, which is secreted from both follicles and corpus luteum in female Japanese monkeys, were also low (300.5–585.0 pg/ml). This strongly suggests that no follicular development occurs during lactation. Serum concentrations of cortisol (261.0–519 ng/ml) were higher during lactation than during the nonbreeding season. Since babies were often seen suckling their mothers during the study, the results indicate that the increased cortisol levels were associated with suckling‐induced secretion of corticotrophin‐releasing hormone (CRH) and adrenocorticotropic hormone (ACTH). The results of this study indicate that a long period of postpartum infertility in lactating Japanese monkeys, with apparent inhibition of follicle growth and anovulation, is due to weak gonadotropin stimulation, which may occur as the result of a suckling stimulus. Zoo Biol 22:65–76, 2003. © 2003 Wiley‐Liss, Inc.     

Morphological changes in the human endocrine pancreas induced by chronic excess of endogenous glucagon.

The non-tumoral endocrine pancreas from a patient with elevated plasma levels of glucagon due to a malignant glucagonoma was studied immunocytochemically, ultrastructurally and morphometrically. Compared with normal pancreatic islets from control subjects, those of the pancreas from the patient with a glucagonoma showed an almost complete disappearance of A cells, a decrease in immunoreactive insulin in B cells associated with cytological features indicating enhanced synthesis and secretion of this hormone, and an increase in immunoreactive somatostatin and pancreatic polypeptide (PP) accompanied by unusually high numbers of D and PP cells. In addition, numerous B cells were found outside the islets, either forming micro-islets or scattered in the exocrine tissue (nesidioblastosis). The possible mechanisms involved in determining the changes in the secretory activity of B cells and the alterations in the cell composition of the islets are discussed.     

Plasminogen activator synthesis by cultured human embryonic lung cells: Characterization of the suppressive effect of corticosteroids

The synthesis of plasminogen activator (PA) by cultured human embryonic lung (HuEL) cells has been examined. The production of PA by these cells was found to be reversibly inhibited by physiological levels of glucocorticoids. The suppression of PA synthesis in HuEL cells was not accompanied by an inhibition of cell growth. Moreover, the glucocorticoid induced deinduction of plasminogen activator synthesis occurred in both growing and non-growing cells. The inhibition of PA production by corticosteroids appeared to have a requirement for DNA-dependent RNA synthesis since the inhibition of DNA-dependent RNA synthesis at the time of exposure of cells to corticosteroids prevented the deinduction of PA.     

Expression of yellow tail (Seriola quinqueradiata) fish growth hormone cDNA in the marine photosynthetic bacterium Rhodobacter SP NKPB 0021

Summary A full length cDNA encoding yellow tail (Seriola quinqueradiata) growth hormone has been cloned into an expression vector, pUK319, which contains a Rhodobacter specific replicon. The resulting plasmid, pKGH319 was introduced by transformation into the marine photosynthetic bacterium Rhodobacter sp. strain NKPB0021. The plasmid was maintained as an autonomous replicon and showed good stability in the absence of antibiotics. Fish growth hormone was purified by HPLC from yellow tail pituitary glands and used to raise polyclonal antibodies for immuno blot analysis of Rhodobacter recombinants. Recombinant growth hormone was immunoreactive to mouse antiserum against natural yellow tail hormone. Our results suggest that the fish growth hormone gene was expressed under the lac promoter of Escherichia coli to levels suitable for the use of recombinant photosynthetic bacteria as a marine fish feed supplement.     

Immunochemical demonstration of increased accumulation of ornithine decarboxylase in rat liver after partial hepatectomy and growth hormone induction

Antiserum against ornithine decarboxylase (EC 4.1.1.17) was prepared in rabbits using purified ornithine decarboxylase from rat liver as the antigen. Immunoglobulins from the immune sera were covalently coupled to agarose by cyanogen bromide activation. With the aid of this immunoadsorbent against the enzyme it has been shown that following partial hepatectomy and growth hormone administration, the ornithine decarboxylase activity is elevated concomitantly with the increase in the immunoreactive enzyme protein. In addition, the rapid decay in ornithine decarboxylase activity in regenerating rat liver after cycloheximide injection is accompanied by a decrease in the immunoreactive protein. These results suggest that the activity of ornithine decarboxylase in rat liver is regulated through rapid changes in de novo synthesis and degradation of the enzyme protein.     

Glycosylated growth hormone: detection in murine pituitary gland and evidence of physiological fluctuations

We examined murine pituitary glands for glycosylated growth hormone using a lectin-binding immunoassay. Every gland tested exhibited significant concanavalin A-binding growth hormone immunoreactivity. The activity was lower in female rats than in males, and lower in lactating than in virgin females. The activity increased following ovariectomy, although total immunoreactive growth hormone was not altered. Administration of estradiol benzoate decreased the concentrations of both types of growth hormone. Progesterone administration, in contrast, did not change concanavalin A-binding growth hormone, but it lowered total growth hormone. Western blotting revealed a growth hormone immunoreactive band 4-5K heavier than the growth hormone monomer in both rat and mouse pituitary. These data suggest the existence in the murine pituitary of a glycosylated form of growth hormone that undergoes physiological fluctuations.     

Production of immunoreactive calcitonin and parathyroid hormone by embryonal carcinoma cells: alteration with retinoic acid-induced differentiation

To determine possible ectopic production of, and altered responsiveness to, specific hormones and growth factors which may be involved in mediating embryonic differentiation and development embryonal carcinoma cells in culture have been employed to serve as an in vitro system of embryogenesis. Exposure of F9 embryonal carcinoma cells to all-trans-retinoic acid previously has been shown to induce differentiation of these undifferentiated stem cells to parietal endoderm and to markedly alter the ability of calcitonin and parathyroid hormone to stimulate adenylate cyclase activity. Evidence is presented that F9 cells secrete immunoreactive calcitonin into the culture medium (200 pg/12 hr/10(7) cells) while parietal yolk sac (PYS) cells secrete immunoreactive parathyroid hormone (800 pg/12 hr/10(7) cells). Retinoic-induced differentiation of F9 cells to endoderm results in a progressive reduction in immunoreactive calcitonin production, while there is an increase in the level of immunoreactive parathyroid hormone found in the conditioned medium. After exposure of F9 cells to retinoic acid for 5 days, little calcitonin is detectable in 12-hr conditioned medium. Changes in the intracellular levels of immunoreactive calcitonin and PTH follow a pattern similar to that noted for changes in the amount of secreted hormones. Thus, immunoreactive calcitonin is produced by undifferentiated F9 cells which possess a calcitonin responsive adenylate cyclase system, while parathyroid hormone is produced by parietal endoderm cells which respond to parathyroid hormone with increased cyclic AMP synthesis. Sephadex G50 gel filtration of F9-conditioned medium shows two peaks of immunoreactive calcitonin with Mr of 3500 and 20,000. Immunoprecipitation of calcitonin from 35S-labeled F9 cells reveals a specific band of 20,000 Mr. Likewise, two peaks of parathyroid hormone immunoreactive material of Mr 8000 and 39,000 are noted after gel filtration of PYS cell-conditioned medium, whereas parathyroid hormone immunoprecipitation from the same cells reveals a specific band of 39,000 Mr. These results raise the possibility that embryo production of these two hormones at specific stages in development may contribute to the regulation of subsequent steps of differentiation.     

Evidence for cigarette smoke-induced calcitonin secretion from lungs of man and hamster

In hamsters, acute cigarette smoke inhalation increased serum levels of the hormone calcitonin; and, in humans, smoking of two high-nicotine content cigarettes increased serum and urine levels of this hormone. The source of this immunoreactive calcitonin (iCT) does not appear to be the thyroid gland, since previously thyroidectomized patients demonstrated a similar response. In the hamster, the increased serum iCT levels were accompanied by a decreased lung tissue iCT content and hypocalcemia. It is suggested that the source of the cigarette smoke-induced hypercalcitonemia is the lung, possibly from the iCT-containing pulmonary neuroendocrine (PNE) cells. Moreover, this response appears to be dependent on the nicotine content of the cigarettes.     

Metabolic Responses to Oral Glucose in the Kalahari Bushmen

The plasma glucose, immunoreactive insulin, and growth hormone levels after a 50-g oral glucose load have been measured in 15 adult Bushmen subjects living in the Kalahari region of Southern Africa. Compared with 10 non-obese white controls, they showed relative glucose intolerance and significantly impaired insulin secretion. Growth hormone responses showed no significant differences between the two groups. Factors such as inadequate or unusual nutrition and stress do not appear to account completely for the abnormalities in carbohydrate metabolism observed in the Bushmen. Of interest are the clinical and hormonal similarities that seem to exist between the Bushmen and the Central African Pygmies.     

Fetal and maternal endocrine responses to exercise in the pregnant ewe

Maternal and fetal concentrations of plasma insulin, pancreatic glucagon, growth hormone (GH), corticosteroids and enteroglucagon, and of blood glucose and lactate, were measured in well-fed, late pregnant ewes before, during and after walking on a treadmill at 0.7 m.s-1, 10 degrees slope for 60 min. Exercise caused rapid and substantial increases in maternal concentrations of glucose, lactate, pancreatic glucagon and corticosteroids, smaller but significant decreases in levels of GH and enteroglucagon, and no change in insulin. With the exception of GH, concentrations of these maternal hormones had returned to pre-exercise levels within 20 min of stopping exercise. The exercise-induced maternal hyperglycaemia was associated with a proportionately similar, rapid increase in fetal blood glucose; fetal blood lactate and plasma corticosteroids also increased, but at slower rates and other fetal hormone concentrations were unchanged. During recovery there was a rapid increase in fetal insulin levels. The results are discussed in terms of the regulation of exercise-induced changes in maternal energy metabolism, and fetal metabolic and hormonal sensitivity to these changes.     

Immunocytochemistry of somatotrophs,gonadotrophs, prolactin and adrenocorticotropin cells in larval sea bream (Sparus auratus) pituitaries

Summary The chronological appearance of endocrine cells in the pituitary of sea-bream (Sparus auratus) larvae was studied using antisera against salmon prolactin, trout growth hormone, salmon gonadotropin and N-terminal human adrenocorticotropin. The larval pituitary (1–12 days after hatching) was oval in shape and was composed of a dense mass of cells with few neurohypophysial fibres. By 60 days after hatching it began to resemble the adult and was divisible into a distinct rostral pars distalis containing prolactin and adrenocorticotropin cells; a proximal pars distalis containing somatotrophs and gonadotrophs and a pars intermedia. Cells immunoreactive with antisera against growth hormone were observed immediately after hatching (2 days post-fertilization). Weakly staining prolactin cells were observed 2 days later in the region corresponding to the rostral pars distalis. Cells immunoreactive with anti-gonadotropin and anti-adrenocorticotropin sera were observed in the pituitary 6 and 8 days after hatching, respectively. All the cell-types studied were immunoreactive from the time they were first identified until the final samples 90 days after hatching.     

Endocrine and behavioral effects of neuromedin S

The present experiments focused on the effects of neuromedin S on hypothalamic–pituitary–adrenal (HPA) activation and behavior. The peptide (0.25–1 nmol) was administered intracerebroventricularly to rats, the behavior of which was monitored by means of telemetry, open field observations and an elevated plus-maze (EPM) test. Autonomic functions such as the temperature and the heart rate were recorded by telemetry. The action on the HPA axis was assessed via measurements of the plasma corticosterone and ACTH levels. To reveal the transmission of the endocrine responses, animals were pretreated with corticotrophin releasing hormone receptor (CRHR) antagonists (1 nmol). In the open field test, the animals were pretreated with either a CRHR₁ antagonist (antalarmin) or haloperidol (10 μg/kg), while in the EPM test they were pretreated with antalarmin or diazepam (1 mg/kg). The dopamine release from striatal and amygdala slices after peptide treatment was measured with a superfusion apparatus. Neuromedin S exerted dose-dependent effects on the HPA system, which were inhibited by antalarmin. It also activated grooming and decreased the entries to and time spent in the open arms during the EPM test. The grooming response was abolished by haloperidol and antalarmin pretreatment, while diazepam and antalarmin showed a tendency to attenuate the response evoked in the EPM test. In the superfusion studies, neuromedin S enhanced the dopamine release from the amygdala slices. These results demonstrate that neuromedin S stimulates the HPA axis through the CRHR₁ pathway and evokes stereotyped behavior and anxiety through mesolimbic dopamine and corticotrophin releasing hormone release.     

Adrenocortical and thyroid systems of rats at the initial stage of nociceptive influence

There are two phases in the initial period of formation of adrenocortical response to sharp nociceptive influence. The first phase (within 10-15 sec.) involves emergency mobilization of "basal" reserves of hormone active substances. It is characterized by reduction of corticoliberine activity in hypothalamic and extrahypothalamic structures of the rat brain with a parallel increase of corticotrophin concentration in plasma, devastation of corticosteroid reserves in adrenal glands; a decrease in the level of corticosteroids in blood against the background of accumulating hormone in bodies-targets. In the second phace: the phase of hypercompensation, the progressive increase of credit of the substances under study was quite obvious. The authentic changes in a level of aldosterone in adrenal glands and blood took place only in 2.5 minutes after the stress. The nociceptive influence was also biphasic when acting upon the reorganization of thyroid status number. However, unlike the initial adrenocortical response to stress in the first phase of thyroid reaction, the elevation of plasma thyroxine and tri-iodothyronine level was obvious. At the second stage, selective decrease in concentration of thyroxine to normal amounts occurred.     

The effect of exogenous growth hormone on insulin requirements during closed loop insulin delivery in insulin-dependent diabetes mellitus

The amount of insulin required to maintain similar blood glucose concentrations during an eight hour infusion of either saline or growth hormone (2 micrograms/kg/hr) was determined in five fed, insulin-dependent diabetic subjects during closed-loop insulin delivery. Elevations of serum growth hormone concentrations to levels previously observed in poorly controlled diabetic subjects were not accompanied by differences in the amount of insulin required to maintain blood glucose concentrations at levels comparable to those observed during the saline infusion. Specifically, no early insulin-like nor late anti-insulin effects of physiologic increases in serum growth hormone concentrations (10.27 +/- 0.23 mg/ml vs 5.69 +/- 1.5 mg/ml, P less than 0.05) on mean hourly blood glucose levels or mean hourly insulin requirements were observed. These studies suggest that serum growth hormone concentrations similar to those observed in poorly controlled diabetics do not affect the insulin requirements of well-insulinized diabetic subjects.     

Plasma immunoreactive corticotrophin and lipotrophin in Cushing's syndrome and Addison's disease.

Plasma immunoreactive corticotrophin (ACTH) and lipotrophin (LPH) were measured in patients with raised circulating concentrations from a pituitary or an ectopic source. They were measured again in seven patients after they had received hydrocortisone. Plasma ACTH concentrations were higher than LPH concentrations in patients with a pituitary source of their hormones, whereas this relation was reversed when the source was ectopic. After hydrocortisone administration the half life of immunoreactive ACTH was 40 minutes and that of LPH 95 minutes, resulting in a reversal of the normal relation of ACTH to LPH. The use of two antisera with different specificities for measuring LPH has further shown that pituitary LPH differs from ectopic LPH. Relatively less gamma-LPH than beta-LPH was produced from ectopic sources, the relation being reversed in patients with a pituitary source for their raised concentrations. Measuring plasma LPH as well as ACTH might therefore help in deciding whether a patient with Cushing''s syndrome has a pituitary or ectopic source of ACTH, which sometimes presents a difficult clinical problem.     

Stimulation of the hypothalamic-pituitary-adrenal axis and inhibition of growth hormone release via increased central noradrenaline neuronal activity by urethane anaesthesia in the rat: blockade by clonidine

Computerized gas chromatography-mass spectrometry was used to measure precisely the hypothalamic levels of noradrenaline (NA), dopamine and serotonin together with those of their major neuronal metabolites 3,4-dihydroxyphenylethyleneglycol (DHPG), 3,4-dihydroxyphenylacetic acid and 5-hydroxyindoleacetic acid in normal male rats 45 min after stimulation of hypothalamic-pituitary-adrenal function by urethane (1.3 g/kg) administration. Urethane treatment resulted in a significant elevation of central noradrenergic neuronal activity (NNA) as assessed from marked rises in hypothalamic DHPG concentrations and the ratio (DHPG/NA). At the same time there was significant stimulation of ACTH and corticosterone release and inhibition of growth hormone release. These hormonal and central effects of urethane (but not anesthesia) were inhibited when the alpha 2-agonist clonidine (150 micrograms/kg) was co-administered. Urethane had no major effect on hypothalamic dopamine or serotonin status. We propose that the release of ACTH and the suppression of growth hormone release following urethane anaesthesia is a result of activation of central NNA and suggest that the hormonal responses are mediated via hypothalamic noradrenergic facilitation of corticotrophin releasing factor and somatostatin release to the anterior pituitary.