Potential limitations of recrystallization for the definitive identification of radioactive steroids

The usefulness of recrystallization in establishing the radiochemical purity of steroids is widely recognized, but the potential limitations of the technique have received little attention. The current study reports the failure of standard recrystallization procedures using methanol/water as the solvent pair to separate contaminating ¹⁴C-17-hydroxyprogesterone (17-hydroxy-4-pregnene-3, 20-dione) from ³H- and ¹⁴C-labeled 11-deoxycortisol (17,21-dihydroxy-4-pregnene-3,20-dione) despite ten serial crystallizations. The standard criteria of radiochemical purity were met despite gross impurity of the crystals as evidenced by thin layer chromatography. Thus, recrystallization may, under certain conditions, yield misleading results when employed as the only method for identifying radioactive steroids. These observations illustrate the importance of an optimal choice of solvent and crystallization conditions, and emphasize the need for confirmation by derivative formation and chromatography.     

Predominant involvement of mu-rather than delta- or kappa-opiate receptors in LH secretion

Opiate alkaloids and opioid peptides have been shown to suppress plasma LH and FSH levels via a naloxone sensitive mechanism in several species including man. Three subtypes of opiate receptors have been characterized: mu, delta and kappa. The present study was designed to investigate their role in gonadotropin release. Three highly selective opioid ligands, DAGO, MRZ and DTE12 (a dimeric tetrapeptide enkephalin), were injected intraventricularly into chronically ovariectomized rats. Injection of the mu-agonist at doses of 1 and 10 nmol produced a significant suppression of LH secretion, while the delta- and kappa-agonists had no significant effect. Thus, the mu-receptor seems to be the primary opiate receptor involved in the regulation of LH secretion. None of the opiate agonists employed had an effect on FSH secretion.     

Hemodynamic and endocrine parameters in the anesthetized cynomolgus monkey: a primate model

Hemodynamic and endocrine parameters were determined in nine anesthetized adult male cynomolgus monkeys. Simultaneous phasic and mean pressures were measured in the right atrium, pulmonary artery, and abdominal aorta. Intermittent pulmonary artery wedge pressures and mean cardiac output measured by the thermal dilution method were used to calculate stroke volume, systemic vascular resistance, and pulmonary vascular resistance. Plasma adrenocorticotropic hormone (ACTH), cortisol, and plasma renin activity were measured throughout the procedure. Technical aspects, data in the anesthetized monkey, and comparison with previously reported data are presented.     

Steroid biosynthesis in human adrenal tumors

Patients with adrenal tumors present with varied clinical features which may be related to differing patterns of adrenal steroidogenesis. To explore the mechanism underlying these differences, we studied the in vitro activities of 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD), 17-hydroxylase (17-OH), 21-hydroxylase (21-OH), and 17-20 desmolase (17, 20-D) in 6 adrenal tumors, 4 adenomas and 2 carcinomas. Normal human adrenal tissue was also studied for comparison. Adrenal adenomas had increased 21-OH activity compared with normal adrenal tissue (11.4 +/- 0.7 vs 5.5 +/- 0.5 nmol/mg prot/min, P less than 0.002) and with adrenal carcinomas (11.4 +/- 0.7 vs 3.3 +/- 0.9 nmol/mg prot/min, P less than 0.001). Carcinomas had reduced 3 beta-HSD, 17-OH and 17,20-D activities when compared to controls, but this did not reach statistical significance. These observations suggest less efficient steroidogenesis by adrenal carcinomas, a finding which may explain the large size of these tumors when the symptoms of hypercortisolism first appear.     

Idiopathic precocious puberty in the chimpanzee: a case report

A female chimpanzee developed premature sex skin swelling, breast budding, advanced bone age, and moderate estrogen effect of the vaginal cytology. Extensive radiographic and hormonal studies excluded all the known causes of precocious puberty and pseudopuberty, yielding a diagnosis of idiopathic true precocious puberty. To our knowledge this is the first observation of idiopathic true precocious puberty in a chimpanzee.     

Late-onset 21-hydroxylase deficiency is an allelic variant of congenital adrenal hyperplasia characterized by attenuated clinical expression and different HLA haplotype associations

Three families with late-onset 21-hydroxylase deficiency were studied. Homozygous females presented with symptoms of mild hyperandrogenism such as acne, hirsutism, oligomenorrhea and menometrorrhagia. A homozygous male was asymptomatic and had reached normal adult height. The diagnosis of 21-hydroxylase deficiency was based upon markedly elevated responses of plasma 17-hydroxyprogesterone during a short (30-min) ACTH infusion test. The propositi of two of the families were diagnosed despite long-standing glucocorticoid therapy and adrenal suppression by using a prolonged (48-hour) ACTH infusion. Heterozygotes of late-onset 21-hydroxylase deficiency had mildly elevated 17-hydroxy-progesterone responses to ACTH. Late-onset 21-hydroxylase deficiency was inherited as an autosomal recessive trait with close linkage to the histocompatibility leukocyte antigens. The B14 haplotype was present in all affected members. One affected female had a daughter with classic, salt-losing 21-hydroxylase deficiency. Mixed heterozygosity of this patient for a classic and a late-onset 21-hydroxylase deficiency allele may have caused the classic phenotype in her daughter (homozygote for 2 classic alleles).     

Acute exercise stimulates the renin-angiotensin-aldosterone axis: adaptive changes in runners

The plasma concentrations of aldosterone and its known regulators, plasma renin, potassium and ACTH, were examined during graded intensities of treadmill exercise (50, 70 and 90% of maximal oxygen uptake, VO2max). Sedentary men (n = 7) and two groups of runners of different training status (moderately trained, 15-25 miles/week, n = 7; highly trained, greater than 45 miles/week, n = 7) were studied in an attempt to define whether physical training causes changes in aldosterone homeostasis. Acute exercise was associated with elevations in plasma aldosterone, renin activity, potassium and ACTH in all three groups of subjects at exercise intensities of 70 and 90% VO2max. There were no differences in any of the responses among the three groups except for a blunted response of PRA at 90% VO2max in highly trained athletes. The exercise-induced rise of plasma aldosterone concentration did not correlate with changes in the concentration of its regulatory substances. We conclude that exercise stimulates the renin-angiotensin-aldosterone axis in an intensity-dependent fashion. With increased physical training identical hormonal and metabolic responses result at increased absolute workloads.