Effect of bombesin on basal and stimulated secretion of some pituitary hormones in humans

The effect of bombesin (5 ng/kg/min X 2.5 h) on basal pituitary secretion as well as on the response to thyrotropin releasing hormone (TRH; 200 micrograms) plus luteinizing hormone releasing hormone (LHRH; 100 micrograms) was studied in healthy male volunteers. The peptide did not change the basal level of growth hormone (GH), prolactin, thyroid-stimulating hormone (TSH), luteinizing hormone (LH) and follicle-stimulating hormone (FSH). On the contrary, the pituitary response to releasing hormones was modified by bombesin administration. When compared with control (saline) values, prolactin and TSH levels after TRH were lower during bombesin infusion, whereas LH and FSH levels after LHRH were higher. Thus bombesin affects in man, as in experimental animals, the secretion of some pituitary hormones.     

Steroid hormones and their receptors in the brain

Steroid hormones regulate several important functions of the brain by altering the expression of particular genes through their receptors. First in this paper the localization of glucocorticoid receptor immunoreactivity and mRNA in the brain was examined. Second biphasic effects of glucocorticoid on the hippocampus was described and particular emphasis was given on the apoptosis. Third the significance of estrogen receptor in the sexually dimorphic areas was discussed. These results suggest that steroids modulate the gene expression along with the alteration of cell structures in a different manner in a tissue-specific pattern.     

Direct effects of heparin on basal and stimulated aldosterone production in rat adrenal glomerulosa cells

Direct effects of heparin (0.1-10 IU/ml) on basal and stimulated aldosterone production have been studied using intact rat adrenal glomerulosa cells. Heparin at any dose did not affect basal aldosterone production when added to the incubation medium. Heparin at a 0.01 IU/ml dose had no effect on aldosterone production maximally stimulated by angiotensin II (AII, 4.8 X 10(-8) M), ACTH (4.3 X 10(-9) M) or potassium (8.0 mM). However, heparin at 0.1 and 0.3 IU/ml doses selectively blocked aldosterone production maximally stimulated by AII but not by ACTH or potassium, while the compound at 1 and 10 IU/ml doses inhibited aldosterone production maximally stimulated by these three stimuli. In addition, the inhibitory effect of 0.3 IU/ml heparin occurred as early as 30 min after incubation with heparin. These data suggest that heparin at 0.1 and 0.3 IU/ml doses acts directly on adrenal zona glomerulosa to selectively block the stimulatory action of AII, while the compound at 1 and 10 IU/ml doses inhibits all the stimulatory actions of AII, ACTH and potassium.     

Steroid hormones and the fertilizing capacity of spermatozoa

The effects of eleven different steroid hormones on $\text{in vitro}$ development of fertilizing capacity by hamster sperm were examined. Capacitation of epididymal sperm occurred only in the presence of female genital tract secretions. Fertilizing ability of sperm was poor if estradiol-17β, cortisol, chlormadinone acetate, medroxyprogesterone acetate, or megestrol acetate were present in the incubation medium at 10^?5M, whereas similar concentrations of estradiol-17α, progesterone, norethisterone acetate, ethynodiol diacetate, or norgestrel had little effect. Testosterone was a weak inhibitor of capacitation. Capacitation activity of female uterus and oviduct washings was higher at estrus than diestrus. This activity was reduced by treating intact animals with progesterone, cortisol, or testosterone, but increased by estradiol-17β or HCG. Estradiol-17α has no effect. Activity was low in pregnant or ovariectomized hamsters. Treatment of ovariectomized animals with estradiol-17β increased capacitation activity, but estradiol-17α, HCG or progesterone treatment was ineffective.     

Steroid hormones and embryo development in ovariectomized hamsters

Preimplantation embryo development was arrested at the premorula stage in hamsters ovariectomized on Day 1 of pregnancy. This effect was reversed when 500 micrograms progesterone were administered daily. Oestradiol-17 beta given alone had no significant effect on the cleavage rate or blastocyst formation, but a synergistic response was evident when a suboptimal (30 micrograms) dose of progesterone was given with 50 ng oestradiol-17 beta. Cholesterol and hydrocortisol had no effect on embryo development.     

Urinary cortisol and cortisol metabolites in women with idiopathic hirsutism.

Urinary unconjugated cortisol, total 17-oxogenic steroids and cortisol metabolites (THF, allo-THF, THE, cortol and cortolone) were measured in 90 normal women and in 90 women with idiopathic hirsutism of comparable age group. After carrying out Student's "t"-test, the mean steroid excretion values in hirsute women were significantly higher than those from normal females. The results indicate that, due to stress, these hirsute women do have altered adrenocortical function, as assessed by the estimation of these corticosteroids of which urinary unconjugated cortisol was found to be the most sensitive index.     

Urinary pregnanetriol and delta 5-pregnentriol in women with idiopathic hirsutism

Urinary pregnanetriol and delta 5-pregnenetriol were determined in 90 normal women and in 90 women with idiopathic hirsutism of comparable age group. When group Student's "t"-test was carried out, the mean steroid excretion values in hirsute women were found to be significant with delta 5-pregnenetriol more significant than pregnanetriol. Of the 90 women with hirsutism, 8 patients had pregnanetriol and delta 5-pregnenetriol values higher than normal. When, on the basis of these elevated values, the women were sent for a thorough gynaecological investigation, they were found to have the polycystic ovary syndrome. After wedge resection, the diagnosis was confirmed and the urinary excretion of pregnanetriol and delta 5-pregnenetriol came down to a normal level. This study shows that, in the case of women with idiopathic hirsutism suspected of any ovarian disorder, the measurement of these two steroids could be of diagnostic importance.     

Urinary testosterone and epitestosterone excretions in women with idiopathic hirsutism.

Urinary testosterone and epitestosterone were determined in 90 normal healthy women and in 90 women with idiopathic hirsutism, both groups aged between 16 and 46 years. Testosterone and epitestosterone excretion values were above the normal range in 27 of the 90 hirsute women (30%), and these 27 women had much more prominent hair growth than the others. When these results were statistically analysed according to the age groups or for all ages as a whole, they were found to be highly significant (P less than 0.0005). Therefore, it is concluded that the estimation of urinary testosterone and epitestosterone could be meaningfully applied to study the androgen status of hirsute women.     

Biomechanics of the venous wall under simulated arterial conditions

The failure of vein graft conduits implanted in the arterial circulation has been hypothesized to occur in part due to the exposure of the graft to altered biomechanical and fluid shearing forces. In the present study, these forces are characterized for canine internal jugular veins (IJV) exposed to realistic arterial flow dynamics. Freshly excised vein segments were mounted into a pulsatile perfusion apparatus and exposed to arterial flow conditions (P = 115/75 mmHg and Q = 110 ml min-1) for 2 h. Dynamic measurements of intraluminal pressure and flow rate and vessel wall radial distension were acquired to accurately quantitate the incremental modulus of elasticity; hoop, axial and radial wall stresses; and fluid shearing forces within the vessel. Identical measurements were performed on canine carotid arteries (CCA) to serve as a comparison. Under arterial conditions, IJV segments demonstrated a significant elevation (p less than 0.05) over the CCA in the incremental elasticity modulus, along with a corresponding elevation in hoop and axial wall stresses. Additionally the average wall shearing rate to which the IJV endothelial surface was exposed was a factor of six less than that observed in the CCA. These results are discussed in relationship to the clinical situation of vein graft adaptation to arterial hemodynamics.     

Prevalence of polycystic ovaries in women with anovulation and idiopathic hirsutism.

Polycystic ovaries were defined with ultrasound imaging in a series of 173 women who presented to a gynaecological endocrine clinic with anovulation or hirsutism. Polycystic ovaries were found in 26% of women with amenorrhoea, 87% with oligomenorrhoea, and 92% with idiopathic hirsutism--that is, hirsutism but with regular menstrual cycles. Fewer than half the anovulatory patients with polycystic ovaries were hirsute, but in 93% of cases there was at least one endocrine abnormality to support the diagnosis of polycystic ovaries--that is, raised serum concentrations of luteinising hormone, raised luteinising hormone: follicle stimulating hormone ratio, or raised serum concentrations of testosterone or androstenedione. This study shows that polycystic ovaries, as defined by pelvic ultrasound, are very common in anovulatory women (57% of cases) and are not necessarily associated with hirsutism or a raised serum luteinising hormone concentration. Most women with hirsutism and regular menses have polycystic ovaries so that the term "idiopathic" hirsutism no longer seems appropriate.     

Steroid regulation of monoamine oxidase activity in the adrenal medulla

Administration of different steroid hormones in vivo has distinct and specific effects on the MAO activity of the adrenal medulla. In an effort to reconstitute these effects in defined cells, we have isolated endothelial cells and chromaffin cells from the bovine adrenal medulla and tested each cell type for sensitivity to these steroids. As in the intact animal, we found that endothelial cell MAO activity was stimulated 1.5- 2.5-fold by 10 microM progesterone, hydrocortisone, and dexamethasone, inhibited by ca. 50% by 17-alpha-estradiol, but unaffected by testosterone. The type of MAO in the endothelial cells was found to be exclusively of the A type. The chromaffin cells had MAO B exclusively and were inert to treatment with dexamethasone. The mode of action of the various steroids on MAO A activity in endothelial cells seemed to be that of affecting the number of MAO molecules, as binding of [3H]pargyline, an MAO inhibitor, changed in proportion to changes in enzyme activity. Consistently, the kinetic parameters for MAO A showed changes in Vmax but not Km under all conditions. The specificity of steroid action on MAO A activity was also supported by the fact that steroid-induced changes in total cell division ([14C]thymidine incorporation) and total protein synthesis ([14C]leucine incorporation) were seen after changes in MAO A. We conclude that the differential effects of steroids on MAO activity in the intact adrenal medulla can be reproduced in cultured adrenal medullary endothelial cells but not in chromaffin cells. Therefore we suggest that the action of these steroid hormones on the intact adrenal medulla may be restricted to the endothelial cell component of this tissue.     

Further evidence for the usefulness of the salivary testosterone radioimmunoassay in the assessment of androgenicity in man in basal and stimulated conditions

Since correct assessment of testicular function and androgenic status in humans requires multiple sampling, a sensitive and accurate radioimmunoassay (RIA) of testosterone (T) was established for male and female saliva samples. This easily collected biological fluid, which contains nonprotein-bound T, may represent an attractive alternative or a complement to total plasma T assays. In saliva samples from 5 normal males, a clear circadian rhythm was observed, and morning concentrations (135 +/- 31 pg/ml) were significantly higher (p less than 0.02) than evening samples (85 +/- 23 pg/ml). In 11 normal females, morning saliva levels were 12.8 +/- 1.8 pg/ml. The levels of T in male saliva, in response to both exogenous T administration (100 mg i.m.) and HCG stimulation (2 X 2,000 IU i.m.), accurately reflected the changes observed in plasma T, and the magnitude of increase in T levels was clearly greater in saliva than in plasma samples during the intramuscular administration of the long-acting T preparation. In males, significant correlations were observed between salivary and plasma T concentrations in morning samples (r = 0.61, p less than 0.01), following HCG stimulation (r = 0.89, p less than 0.05) and during T administration (r = 0.87, p less than 0.05). In women, the correlation at 8 a.m. was also significant (r = 0.82, p less than 0.05).