Effects of an anabolic steroid on reproduction in female rats

Mature female rats given food and water ad libitum and maintained under a lighting schedule of 12h light/12h dark were treated with boldenone undecylenate. Neither dosage nor duration of treatment had a significant effect on weight gain when compared to controls. All treated females were characterized by the absence of cyclic ovarian activity that continued for several weeks following termination of treatment. Long term reproductive performance was altered by a significant reduction in both conception rate and neonatal survival. Behavioral patterns were modified for several months following steroid withdrawal.     

Regulation of leptin gene expression and secretion by steroid hormones.

Previous work has shown that 17 beta-estradiol is the primary ovarian signal regulating body weight and adiposity, although its mechanisms of action remain unclear. We hypothesized that 17 beta-estradiol could enhance leptin levels as a mechanism of its anorectic effects. Administration of 5 microg 17 beta-estradiol subcutaneously (s.c.) for 2 days significantly elevated leptin mRNA levels in adipose tissue as compared to vehicle controls (P < 0.003). A time-course administration of estrogen showed increased mRNA levels in adipose tissue between 6 and 12 h after estrogen injection as compared to vehicle controls (P < 0.03). Corresponding to the increased leptin mRNA levels at 6 and 12 h, elevated plasma leptin levels were observed at 12 h after estrogen administration as compared to controls (P < 0.05). Administration of progesterone (1 mg/rat) after estradiol injection did not enhance the elevated leptin mRNA levels in adipose tissue. Serum leptin levels from cycling rats did not differ significantly between metestrous and proestrous animals. In conclusion, the present studies demonstrate that 17 beta-estradiol can regulate leptin gene expression and secretion in the female rat, thus providing a better understanding of the possible anorectic effect of estrogens.     

Absence of direct effects of GnRH on testicular steroid secretion in the ram

Effects of GnRH, administered via the testicular artery, on testicular steroidogenesis were studied in rams during the non-breeding season. Concentrations of testosterone and 17-hydroxyprogesterone in testicular venous blood showed similar profiles which were identical for GnRH-treated (0.5 ng infused over 60 min or 25 ng injected) and control testes. Increases of testicular venous concentration of both hormones were only marginally reflected in peripheral venous concentrations. Peripheral administration of hCG (200 i.u., i.v.) stimulated testosterone secretion to a larger extent than 17-hydroxyprogesterone secretion in 10/11 rams, GnRH-treated and control testes showing identical responses. High testicular venous concentrations of both hormones after administration of GnRH were paralleled by increased concentrations of endogenous LH. These LH peaks were evoked by 25 ng GnRH in 7/8 rams. The observed effects of GnRH treatment on testicular steroid secretion thus cannot be considered to be the result of direct stimulation of steroidogenesis by GnRH.     

Effects of the anabolic steroid nandrolone phenylpropionate on craniofacial growth in rats

Primary testosterone and its derivatives are anabolic steroids used in the treatment of osteoporosis and Turner syndrome. They also enhance fast-twitch muscle weight in female rats. The present study examines the effect of an anabolic steroid on craniofacial growth and development in rats. Five-week-old female Sprague-Dawley rats (125) were divided into experimental and control groups. The experimental group was injected subcutaneously with 1 mg nandrolone phenylpropionate in the interscapular region on alternate days, whereas those in the control group were injected with a vehicle, arachis oil. Rats were sacrificed at 60 and 120 days of age. Cephalometric analysis of soft X-ray cephalograms showed that chronic administration of the anabolic steroid, nandrolone phenylpropionate, resulted in: (1) about a 20% increase in body weight, (2) an increase in total skull length, (3) elongation of the maxillary and mandibular incisors, (4) an increase in the depth of the antegonial notch, and (5) downward-forward growth of the viscerocranium against the neurocranium. These results suggest that nandrolone phenylpropionate may accelerate craniofacial growth and/or induce high functional activity of the masticatory muscles in female rats. © 1994 Wiley-Liss, Inc.     

Binding of steroid hormones and anabolic agents to bovine sex-hormone binding globulin

Binding of some selected steroids and anabolic agents to bovine sex-hormone binding globulin (SHBG) was investigated. SHBG binding affinities, relative to the reference hormone 5 alpha-dihydrotestosterone, were estimated for the compounds. The results demonstrate that binding of steroid hormones to SHBG is facilitated by the 17 beta-hydroxyl group, possibly involving hydrogen binding, and by the methyl group at C-19 of the steroid moiety. Structural modifications at C-17 of a steroid molecule involving esterification, epimerization or reduction of the 17 beta-hydroxyl group, or introduction of a bulky 17 alpha group have the effect of decreasing the SHBG binding affinity of the steroid molecule.     

Effects of gonadal steroid hormones on hibernation in the Turkish hamster (Mesocricetus brandti)

Summary The Turkish hamster (Mesocricetus brandti) is a photoperiodic species in which exposure to a short day photoperiod induces gonadal atrophy. When hibernating male Turkish hamsters were administered testosterone via subcutaneous silastic capsules hibernation was abruptly terminated. The threshold serum testosterone level required to prevent hibernation was intermediate between the levels observed in males with fully-regressed and fully-functional testes. Dihydrotestosterone was as effective as testosterone in blocking hibernation. Estradiol had a partial inhibitory effect. Progesterone and corticosterone implants had no effect on hibernation. Similar results were obtained in female hamsters. The total period of hibernation for untreated males under laboratory conditions was usually 5–6 months. In most animals testicular growth began to occur toward the end of that period. As gonadal growth continued bouts of torpor decreased in frequency and duration, and hibernation was terminated when the testes approached reproductive size. Castrated males continued to hibernate much longer than intact animals. These observations suggest that in nature decreasing day length in the fall initiates gonadal regression which is followed by cold-induced hibernation. In the spring spontaneous recrudescence of the testes may lead to termination of the dormancy period. This mechanism may enable the species to prepare for the reproductive season with maximum efficiency.Supported by NIH Research Grant HD-10478 and by a grant from the Connecticut Research FoundationThe data in this paper were presented in part at the Annual Meeting of the American Society of Zoologists, Toronto, December 26–30, 1977     

In vitro effects of steroid hormones on IgM-secreting cells and IgM secretion in common carp (Cyprinus carpio)

The effects of steroid hormones on in vitro IgM-secreting cells (IgMSC) and IgM secretion by lymphocytes of the lymphoid organs in common carp, Cyprinus carpio were examined by ELISPOT and ELISA assay, respectively. Cells isolated from peripheral blood (PB), spleen and head kidney were cultured for 12, 24 and 48 h either in the absence or in the presence of steroid hormones, i.e. cortisol, testosterone, 11-ketotestosterone (11-KT), and estradiol-17beta (E(2)) at doses of 1, 10 and 100 ng/ml. Cortisol reduced the IgMSC numbers and IgM secretion by cells from all organs. In addition, cortisol induced apoptosis in lymphocytes from all organs. High dose of testosterone showed tissue-specific functions; it reduced the number of IgMSC and amount of IgM secretion by cells from spleen and head kidney, but not in PB, though IgM secretion was suppressed. However, no effects of sex steroids were observed in this study. The results show that sex-specific steroid hormones may have no immunosuppressive effects in common carp.     

Effects of acute unilateral ovariectomy to pre-pubertal rats on steroid hormones secretion and compensatory ovarian responses

In the present study we analyzed the existence of asymmetry in the secretion of steroid hormones in pre-pubertal female rats treated with unilateral ovariectomy (ULO) or unilateral perforation of the abdominal wall (sham-surgery). Treated rats were sacrificed at different times after surgery. Since sham-surgery had an apparent effect on the age of first vaginal estrous (FVE) and serum levels hormone, the results of the sham surgery groups were used to assess the effects of their respective surgery treatment groups. On the day of FVE, compensatory ovulation (CO) and compensatory ovarian hypertrophy (COH) were similar in animals with ULO, regardless of the ovary remaining in situ. In ULO treated animals, progesterone (P4) levels were higher than in animals with sham-surgery one hour after treatment but lower in rats sacrificed at FEV. Left-ULO resulted in lower testosterone (T) concentration 48 and 72 hours after surgery. In rats with Right-ULO lower T concentrations were observed in rats sacrificed one or 72 hours after surgery, and at FVE. ULO (left or right) resulted in lower estradiol (E2) concentrations one or 72 hours after treatment. In rats with Left-ULO, E2 levels were higher 48 hours after surgery and at FVE. Left-ULO resulted in higher levels of follicle stimulating hormone (FSH) five hours after surgery and at FVE. FSH levels were higher in rats with Right-ULO sacrificed on FVE. The present results suggest that in the pre-pubertal rat both ovaries have similar capacities to secrete P4, and that the right ovary has a higher capacity to secrete E2. Taken together, the present results support the idea that the effects of ULO result from the decrease in glandular tissue and changes in the neural information arising from the ovary.     

Effects of sexual steroid hormones on the functionality of murine peritoneal macrophages.

In the present work, we studied the possible effect of steroid hormones, estradiol, progesterone, and 5 alpha-dihydrotestosterone, on different phenotypic and functional characteristics of peritoneal adherent mononuclear cells. We used female and male mice of Balb/c strain, normal, gonadectomized, and gonadectomized with hormonal replacement. We found that gonadectomy in both sexes produced a significant decrease in the functionality of membrane receptors for the complement and in phagocytic activity of Candida albicans-anti-C albicans system. In addition, the percentages of cells that reduced nitroblue tetrazolium were diminished in castrated animals. Ovariectomized females injected with estradiol presented normal levels of phagocytic and metabolic capacities, but the expression of membrane receptors for complement remained decreased. In contrast, progesterone treatment of ovariectomized animals had the opposite effect. Simultaneous treatment with estradiol plus progesterone gave results similar to those observed with estradiol only. Dihydrotestosterone per se did not affect any of the parameters measured in the conditions used here. These results suggest that female steroids affect macrophage functionality, probably by regulating surface receptors that are involved in phagocytic activity.     

Modulatory effect of steroid hormones on GnRH-induced LH secretion by cultured rat pituitary cells.

The purpose of the present experiments was to examine the short- and long-term effects of estradiol-17 beta (E2), progesterone (P), and 5 alpha-dihydrotestosterone (DHT), alone and in combination, on the gonadotrophin-releasing hormone (GnRH)-induced luteinizing hormone (LH) secretion, using an ovariectomized rat pituitary cells culture model. After 72 h in steroid-free medium, pituitary cells were further cultured for 24 h in medium with or without E2 (1 nM), P (100 nM), or DHT (10 nM). Cultures were then incubated for 5 h in the absence or presence of 1 nM GnRH with or without steroids. LH was measured in the medium and cell extract by radioimmunoassay. The results show that the steroid hormones exert opposite effects on the release of LH induced by GnRH, which seems to be dependent upon the length of time the pituitary cells have been exposed to the steroids. In fact, short-term (5 h) action of E2 resulted in a partial inhibition (64% of control) of LH release in response to GnRH, while long-term (24 h) exposure enhanced (158%) GnRH-induced LH release. Similar results were obtained with DHT, although the magnitude of the effect was lower than with E2. Conversely, P caused an acute stimulatory action (118%) on the LH released in response to GnRH and a slightly inhibitory effect (90%) after chronic treatment. GnRH-stimulated LH biosynthesis was also influenced by steroid treatment. Significant increases in total (cells plus medium) LH were observed in pituitary cells treated with E2 or DHT.(ABSTRACT TRUNCATED AT 250 WORDS)     

Endocrine basis for testicular function in the stallion

The specific nature and relative contribution of the various factors involved in the endocrine/paracrine/autocrine control of reproductive function in normal stallions are not well defined nor have they been elucidated in the idiopathic subfertile/infertile stallion. Over the last 9 years, work in our laboratory has been focused in characterizing the hypothalamic-pituitary-testicular axis in fertile, subfertile (idiopathic oligospermia) and infertile (idiopathic azoospermia) stallions. We have identified endocrine factors and mechanisms important for normal reproductive function, and demonstrated specific hormonal changes in pituitary and testicular function between fertile, subfertile and infertile stallions. Recent evidence suggests that the primary defect is at the level of the testes. The nature of the dysfunction does not appear to involve changes in LH receptor binding kinetics but may be related to post-receptor mechanisms.     

Effects of the anabolic steroid, boldenone undecylenate, on certain reproductive parameters in bulls

A total of 17 bulls was used to study the effects of boldenone undecylenate on growth and semen characteristics in beef bulls. In trial 1 nine mature mixed-breed beef bulls with satisfactory semen quality were divided into two groups. Group I (n = 5) received boldenone undecylenate (1.1 mg/kg) at 21 d intervals for a total of seven treatments (147 d). Group II (n = 4) served as untreated controls. Semen was collected from each group by electroejaculation on each treatment day and evaluated according to the standards of the Society for Theriogenology. Although neither the percentage of spermatozoa with primary or secondary morphological abnormalities was different, the ejaculates of Group I bulls contained a higher percentage of abnormal spermatozoa than those in Group II. In trial 2, eight mixed-breed bull calves, average weight 140.4 kg, were maintained under drylot conditions in a single paddock. The bulls were divided into two equal groups. Group I (n = 4) received boldenone undecylenate as in Trial 1. Group II (n = 4) served as untreated controls. The bulls were weighed and the scrotal circumference (SC) was measured every 21 d until it reached 30 cm, at which time semen was collected and evaluated as in Trial 1. Group I bulls had a higher percentage of spermatozoa with primary morphological abnormalities than bulls in Group II. Group I bulls had a higher average daily gain (ADG) than Group II bulls and required 21 d longer for the SC to reach 30 cm. Semen quality for all bulls was satisfactory at each sampling day.