Endocrinologia Experimentalis

Hormonal parameters (see below) were determined in 78 male acne patients of both sexes (mean age 21.2 +/- 3.8 years; (mean +/- S.D.) and compared with 63 controls (25.0 +/- 4.2 years). In a female group consisting of 60 patients acne (23.2 +/- 5.0 years) and 28 controls (26.1 +/- 5.7 years) of age, blood sampling was performed in the luteal phase of the menstrual cycle. Testosterone (T), dehydroepiandrosterone-sulfate (DHEAS), androstenedione (A), free testosterone (FT) and 17-hydroxy-progesterone (17-OHP) were determined by standard radioimmunoassay methods...

In previous studies, follicular fluid (FF) of large antral follicles (LFF) manifested a stimulatory effect on granulosa cell (GC) luteinization in domestic livestock, but was found to have an inhibitory effect on rodent GC. In the present study, the type of LFF effect on the luteinizing of rat GC was reevaluated in two different models. GC obtained from immature hypophysectomized rats treated with diethylstilbestrol were cultured with increasing concentrations of FSH alone or FSH + estradiol-17 beta (E2), either for 3 or 4 successive days of culture (model 1) or for 4 days of culture with medium change after 2 days of culture (model 2)...

The effects of large doses of thyroid hormone, thyrotropin (TSH) or thyrotropin-releasing hormone (TRH) on pro-TRH concentrations in the rat hypothalamus, cerebrum, cerebellum, brain stem, stomach and eye were studied. The rats were administered T4 (2.5 mg/kg), T3 (375 micrograms/kg), TRH (1.0 mg/kg) or bovine TSH (1.25 IU/kg) i.p. and seven rats in each subgroup were decapitated at 4 or 24 h after the injection. Pro-TRH, TRH, TSH and thyroid hormone were measured by each radioimmunoassay. Immunoreactive pro-TRH (ir-pro-TRH) and immunoreactive TRH (ir-TRH) were found in the hypothalamus, cerebrum, brain stem, stomach and eye...

Corpora lutea removed from ovarian of cycling pigs in early luteal phase (1-3 days) were used. After enzyme dispersion the luteal cells were suspended in medium M 199 supplemented with 10% of calf serum. Cultures were carried out in triplicate and incubated at 37 degrees C for 24 h. After that time the following hormones were added to the culture medium; 100 ng LH, or 100 ng PRL or 100 ng LH plus 100 ng PRL. The cells were incubated with hormone for 6, 12, 24 and 48 h. LH added to the medium resulted in the increase of progesterone secretion (P less than 0...

The effect of nonsteroid antiandrogen flutamide on 3H-testosterone (3H-T) metabolism in vitro was studied in Wistar male rat prostatic and hepatic homogenates. Flutamide was administered per os in a dose of 25 mg/kg daily for 3, 10 or 30 consecutive days. Following 30 days 5 alpha-dihydrotestosterone (DHT) formation in the prostate was reduced by 50%. In castrated animals antiandrogen abolished the recovering action of testosterone propionate (TP) on 5 alpha-reductase activity. When added to incubation medium flutamide proved ineffective, while hydroxyflutamide appeared to decrease DHT formation...

The binding of 3,5,3'-L-triiodothyronine (T3) and thyroxine (T4) on liver nuclear receptors and the activity of malic enzyme and ornithine decarboxylase was examined in infantile rats aged in 1, 3, 7, 23, 29 days and in adult rats. No changes in the affinity constants (Ka) of nuclear receptors were observed for T3 or T4. The maximum binding capacity (MBC) estimated with the use of Scatchard plot analysis was unchanged for T3, the highest MBC for 125I-T4 being noted in rats aged 7 days. Malic enzyme activity in rat liver during the first three neonatal weeks was almost undetectable, but markedly increased on the 29th day...

In a trial with 50 fattening pigs (20 kg initial body weight), the effect of untreated rapeseed meal (RSM) (148 mmol glucosinolates and aglucones per kg dry matter) on the thyroid was compared with RSM treated with Cu2+ (9.5 mmol glucosinolates and aglucones per kg dry matter) and soybean meal (SBM). The diets containing 8% RSM were supplemented with 0.0625-1.0 and the SBM diet (control) with 0.125 mg iodine kg-1 (I). In comparison with SBM fed control, RSM treatment with Cu2+ resulted in a complete normalization of feed intake and growth...

The influence of varying glucoregulatory states as induced by fasting, feeding and intravenous glucose infusion on liver thiol content has been assessed in the male rat. As expected, increasing the serum glucose levels from 131 +/- 7 mg/dl to 343 +/- 12 mg/dl (mean +/- S.E.) caused a corresponding increase in serum insulin responses. Rising from 3.2 +/- 0.4 mumol/g w.w. in the fasted group to a peak value of 6.3 +/- 0.4 mumol/g (P less than 0.01) in the group infused by 10% glucose solution, hepatic non protein bound sulphydryl groups (NP-SH) were closely related to serum glucose levels up to 244 +/- 11 mg/dl...

Granulosa cells were recovered from small (1-3 mm in diameter) and large (greater than 6 mm in diameter) preovulatory follicles or from follicles of early pregnant pigs (3-5 mm, Day 18). Incubation of these cells (5 x 10(5)) was carried out in a shaking water bath (40 degrees C) for 2 h with or without salbutamol (10(-5) M), isoprenaline (10(-5) M), propranolol (10(-5) M) and FSH (100 ng/ml). Isoprenaline significantly increased progesterone production (P less than 0.05) by granulosa cells of small follicles and large preovulatory follicles but not by granulosa cells of follicles from early pregnant pigs...

The ability of intraglandular colloid, the holocrine secretion of cells of the marginal half of the bovine pituitary intermediate lobe, to enhance or suppress the proliferation of immature thymic cells of CH3/6JH mice, 4 to 6 weeks of age, was studied. The mice were given subcutaneous injections of colloid for 3 consecutive days at a dose of 20 mg/kg body weight in 0.2 ml of saline. The analysis of propidium iodide stained thymic cell preparations by means of flow cytometry showed that there was a significant increase in the percentage of cells in the S phase (proliferative phase) of the cell cycle of mice injected with colloid (33%) compared with saline injected (15%) and non-injected controls (7%)...

The effect of glucose on insulin removal by perfused liver of fed and fasted rats has been studied. The perfusion medium contained glucose at a concentration of 300 mg/dl or no glucose. It has been found that glucose has no effect on insulin removal in either group and that fasting had no effect on this process. It is concluded that blood glucose concentration does no influence insulin removal by the liver.

TSH receptors in plasma membranes of thyroid nodular and perinodular tissue and the concentration of thyroid hormones and thyroglobulin in serum were estimated in patients with Hashimoto's thyroiditis (HT) and in six persons with scintigraphically cold thyroid nodules (AFN). In perinodular tissue of HT patients specific binding of 125I-bTSH was found to be significantly decreased (1.50 +/- 0.13%; mean +/- S.E.) as compared with AFN patients (2.79 +/- 0.53%), whereas any significant difference in hormone binding to nodular tissues between both examined groups was not detected...

The effect of pinealectomy on the adrenal growth in unilaterally adrenalectomized rats was studied by evaluation of the mitotic activity of adrenocortical cells on the fifth and tenth day after operation. It was found that pinealectomy resulted in an about double increase of mitotic index on the 5th day after unilateral adrenalectomy, and on the 10th day the stimulatory effect of pinealectomy became less significant.

The influence of a single dose of melatonin administered to pinealectomized and sham operated rats at different times of day on serum T3, T4 concentrations was investigated. It was found that such melatonin influence depends upon a time of day. Both pinealectomy and exogenous melatonin did not influence the thyroid activity in the morning. The most remarkable pineal effect on the thyroid appeared during the night.

The effects of either a single dose or long-term administration of corticosterone or dexamethasone 21-acetate (Dex Ac) on glucocorticoid receptor concentration in mammary gland cytosol of lactating adrenalectomized rats were investigated. Adrenalectomy on lactation day 7 failed to affect the glucocorticoid receptors significantly. Both the natural and synthetic steroid caused a rapid decrease of receptor binding in the cytosol but the time course of glucocorticoid receptor depletion was different. Complete depletion of cytosol receptor was observed after both a single s...

Inhibitory effect of anterior pituitary tissue implanted into the brain on trophic hormone secretion was studied under resting conditions and after adrenalectomy or ether stress. The weight of pituitary gland in rats bearing anterior pituitary graft in the third ventricle was decreased and the body weight gain was retarded. The levels of ACTH, PRL and GH, but not those of FSH and LH in plasma were significantly lower as compared with all control groups. There was a pituitary ACTH, PRL and GH response to adrenalectomy and ether stress in these rats...

Rathke's pouches of 12- and 13-day-old rat embryos were implanted beneath the kidney capsule of adult male rats subjected to the removal of median eminence or to sham-operation. Host animals were sacrificed 28 days after grafting and the implanted pituitaries were processed for immunohistological examination. ACTH, LH-beta, FSH-beta, TSH-beta, GH and PRL immunopositive cells could be observed in fetal grafts of all experimental groups. However, the number and staining intensity of different hormone containing cells largely varied and presumably depended on the hormonal state of host animals...

The effects of Pro-thyrotropin-releasing hormone (TRH), pre-pro-TRH (53-74), pre-pro-TRH (83-106), pre-pro-TRH (115-151), pre-pro-TRH (160-169), pre-pro-TRH (178-199) and TRH on thyrotropin (TSH) and prolactin (PRL) release from the rat anterior pituitary were studied in vitro. The rat anterior pituitary was incubated in medium 199 (pH 7.4) with 1.0 mg/ml of bacitracin (medium) for 30 min. The amount of TSH and PRL release into the medium was measured by radioimmunassay. TSH and PRL release from the anterior pituitary was stimulated with the addition of TRH or pro-TRH in a dose-related manner, but not with other peptides...

The effect of right- or left-sided vagotomy on serum gonadotropin secretion was studied in rats with two testes and in hemicastrates. Right-sided vagotomy in animals with two testes in situ induced a very marked rise in serum LH levels. Left-sided vagotomy was also accompanied with a slight increase in LH secretion. The difference in serum LH levels between right-and left-sided vagotomized animals was significant. FSH levels were unaffected by either right- or left-sided vagotomy. Removal of the right or of the left testis resulted in a significant increase in serum gonadotropin levels...

The objective of this study was to determine the presence of somatostatin-like immunoreactivity (SSIR) in bovine pituitary intraglandular colloid (IGC) of intermediate lobe (IL) origin. Three colloid samples, sufficient to perform the assays, were taken from freshly slaughtered steers, freed of extraneous tissue and lyophilized. The pools were extracted with acetone and petroleum either and the extract radioimmunoassayed for the presence of SSIR. SSIR was present in two of the three samples assayed. We conclude SS is one of the many peptides found in pituitary IGC of IL origin...