Simultaneous Administration Of Testosterone Research Articles

Impairment of spermatogenesis and enhancement of testicular germ cell apoptosis induced by exogenous all-Trans-retinoic acid in adult lizardPodarcis sicula

In mammals, retinoic acid is involved in the regulation of testicular function by interaction with two families of nuclear receptors, retinoic acid receptor (RAR) and retinoid X receptor (RXR). Among RAR isoforms, the testicular cells of the lizard were found to express only RARalpha (3.7 kb) and RARbeta (3.4 kb) mRNAs, as reported here. In this study, the effects of exogenous all-trans-retinoic acid (atRA) on spermatogenesis of a non-mammalian seasonal reproducer were investigated. Daily intraperitoneal injections of atRA or atRA plus testosterone (atRA+T) were given for 2 weeks to adult males of the lizard Podarcis sicula. In animals treated with atRA, the seminiferous tubules were markedly reduced in cross-area. The seminiferous epithelium collapse was responsible for a sensible reduction in the number of germ cells and disruption in normal epithelial organization. In comparison, in atRA+T-treated lizards the loss of germinal cells was significantly less. The loss of germ cells observed in both experimental groups results from an induction of apoptotic process, as revealed by TUNEL analysis. Although low in number, apoptotic germ cells were also observed in the control groups (saline- and T-treated lizard), where the main germ cells undergoing apoptosis are primary spermatocytes (most frequently) and some spermatogonia. In conclusion, it is shown here that retinoic acid has deleterious effects on lizard spermatogenesis, causing a severe depletion of seminiferous epithelium, probably via induction of apoptotic processes. These effects are not completely inhibited by simultaneous administration of testosterone, although this hormone, once injected, is able to stimulate spermatogenesis and protect germinal cells from apoptotic cell death.

Androgen-dependent expression, gene structure, and molecular evolution of guinea pig caltrin II, a WAP-motif protein.

We determined the cDNA and gene structures of guinea pig caltrin II, a unique member of the calcium transporter inhibitors containing a whey acidic protein (WAP) motif, and we established that it is a secretory protein with a potential 21-amino acid signal peptide in its N-terminus. Northern blot analysis and in situ hybridization histochemistry indicated that the expression of caltrin II is restricted to luminal epithelial cells in the seminal vesicles. Its message levels markedly decreased either after castration (and were restored by simultaneous administration of testosterone) or after treatment of the animals with estradiol, suggesting that the expression of caltrin II is androgen-dependent. Recombinant caltrin II had an elastase-inhibitor activity. Comparison of sequence between the caltrin II and related genes and their molecular evolutionary analyses revealed that caltrin II and seminal vesicle secretory proteins (SVPs) appear to be evolved from a common ancestor gene that is made by the fusion of semenogelin and trappin genes. Caltrin II and SVPs lost the transglutaminase substrate domain and the WAP motif, respectively, within a single exon, resulting in the exertion of different functions.

Use of Anabolic Steroids to Attenuate the Effects Glucocorticoids on the Rat Diaphragm

Administration of glucocorticoids results in atrophy and contractile dysfunction in the rat diaphragm. Anabolic steroids may be useful in preventing atrophy and contractile dysfunction. The purpose of this study was to assess the effects of simultaneous administration of testosterone and glucocorticoids on morphological and contractile properties of the rat diaphragm. Eighty-eight adult female Sprague-Dawley rats were divided into 1 of 4 groups: a control group that was given sham injections for 13 days (CONT group, n=23), a group that was given prednisolone injections (0.5 mg/100 g) for 10 days (PRED group, n=23), a group that was given testosterone injections (0.5 mg/100 g) for 13 days (TEST group, n=18), and a group that was given a combination of prednisolone and testosterone injections (0.5 mg/100 g) for 10 and 13 days, respectively (COMBO group, n=23). The animals were weighed daily, and drug doses were adjusted to changes in body mass. Twenty-four hours following the final injection, animals were weighed and sacrificed and the diaphragm was removed and weighed. A small strip of diaphragm was attached to a force transducer to determine normalized maximal isometric tetanic tension (PO). Body weights in the PRED group were decreased by 26% as compared with body weights in the CONT group, and body weights in the COMBO group were decreased by 11% as compared with body weights in the CONT group. Diaphragm weights in the PRED and COMBO groups were decreased by 22% and 12%, respectively, as compared with diaphragm weights in the CONT group. Normalized maximal isometric tetanic tension was decreased by 11% in the PRED group as compared with PO in both the CONT and TEST groups and was decreased by 13% as compared with PO in the COMBO group. There was no difference in PO among the CONT, TEST, and COMBO groups. The results support the hypothesis that simultaneous administration of testosterone with glucocorticoids would prevent a decrease in PO. The results indicate that simultaneous administration of testosterone with glucocorticoids prevented the loss in body weight and partially attenuated the loss in diaphragm weight that is commonly observed when glucocorticoids are given alone. These data support the notion that testosterone may be useful in the prevention of glucocorticoid-induced atrophy.

Autoregulation of androgen receptor protein and messenger RNA in rat ventral prostate is protein synthesis dependent.

In order to investigate the role of protein synthesis in the testosterone regulation of androgen receptor (AR) levels, in vivo studies were undertaken using the ventral prostate gland from adult male rats castrated 24 h previously. Our results showed that testosterone (400 microg/100 g body weight) increased nuclear AR binding 1 h after administration, whereas the protein synthesis inhibitor cycloheximide (400 microg/100 g body weight) by itself did not alter AR binding. However, concomitant administration of testosterone and cycloheximide blocked the testosterone-induced nuclear AR accumulation after 1 h. To determine if changes in AR binding reflected changes in AR protein levels, immunocytochemical studies were conducted on individually dissected ventral prostatic ducts. Castration 24 h previously induced a decrease in nuclear AR immunostaining when compared to intact animals. Testosterone treatment restored the nuclear staining, particularly at the distal tips of the prostatic ducts. Cycloheximide alone did not change AR immunostaining when compared to castrated vehicle-treated rats, yet it significantly decreased the nuclear AR staining induced by testosterone. Our results suggest that AR is being newly synthesized during testosterone treatment. To determine if the effect of testosterone in the regulation of the AR protein was ultimately due to changes at the messenger RNA (mRNA) levels, steady-state AR mRNA levels were measured. Northern blot analysis of poly A+ mRNA preparations revealed that androgen withdrawal for 24 h increased AR mRNA and that testosterone treatment for 1 h did not alter these increased AR mRNA levels. The inhibition of protein synthesis by cycloheximide did not change AR mRNA, but, when cycloheximide was administered in conjunction with testosterone, AR mRNA levels were significantly decreased. In an attempt to relate these responses to changes in transcriptional activity, the transcription inhibitor actinomycin D was administered in vivo. Whereas simultaneous administration of testosterone and cycloheximide modified AR mRNA and AR protein levels, concomitant administration of testosterone with actinomycin D did not alter these levels. It is therefore unlikely that testosterone modifies the transcription of AR mRNA within 1 h after its administration. Collectively, these results suggest that protein synthesis is involved in the mechanism of testosterone-promoted AR regulation. This protein synthesis-dependent mechanism may be involved in the regulation of the stability and/or the translation of AR mRNA in the prostate.

Stress induces neuronal death in the hippocampus of castrated rats

Whereas loss of CA3 neurons in the hippocampus of monkeys which died of stress ulcers suggests that some structural changes may occur, there is no direct evidence that shows stress-induced irreversible changes of neurons. When rats were orchidectomized (castrated) and stressed by restraint and immersion in water for 15 min/day for 30 days, significant loss of hippocampal CA3 and CA4 neurons was observed. Furthermore, primary cultured hippocampal neurons survived shorter when treated with corticosterone. This neuronal loss was prevented by simultaneous administration of testosterone in vivo and in vitro. These findings indicate that stress can contribute to neuronal degeneration associated with hypogonadal conditions such as aging.

Renin in the Rat Pituitary Coexists with Angiotensin II and Depends on Testosterone*

In the rat pituitary gland, immunoreactive angiotensin II (ANG II), renin, and LH, but not PRL, were found within the same cells of the anterior pituitary gland by staining with the avidin-biotin complex method in adjacent sections. No renin-positive staining was observed in the pituitary of the rats after 10 days of castration, but positive staining reappeared after 8 weeks. This effect of castration on renin immunoreactivity was abolished by the simultaneous administration of testosterone. In contrast, ANG II immunoreactivity was unaffected by castration. The intensity of renin immunoreactivity in the pituitary was less prominent in the female than in the male rat. These results suggest that there exists a pituitary renin-angiotensin system localized in the gonadotrophs and that the pituitary renin is under androgenic control.

Androgenic regulation of hepatic metabolism of 4-androstene-3,17-dione in the rainbow trout, Salmo gairdnerII.

The metabolism of 4-androstene-3,17-dione by liver microsomes from the juvenile rainbow trout, Salmo gairdnerii, was studied in vitro. Administration of testosterone, 11 -oxotestosterone, dihydrotestosterone or 17 alpha-methyltestosterone to juvenile fish significantly increased mean hepatic 17-hydroxysteroid oxidoreductase (17-HSOR) activity. Androgen treatment tended to increase the total cytochrome P-450 content significantly in liver microsomes from 11-oxotestosterone-treated fish. On the other hand, androgen treatment decreased mean hepatic 6 beta-hydroxylase activity but did not affect 16-hydroxylase or 5 alpha-reductase activity. The suppressive effect of simultaneous administration of testosterone and oestradiol-17 beta on 6 beta-hydroxylase activity was more pronounced than when these steroids were administered separately. Furthermore, oestradiol-17 beta diminished the effect of testosterone on 17-HSOR activity. Testosterone treatment of hypophysectomized fish caused a significant increase in 17-HSOR activity when compared with activity in untreated hypophysectomized fish, indicating that this effect of testosterone is mainly direct and independent of the pituitary gland. The results indicate that androgens as well as oestradiol-17 beta play a role in the control of sexual differences in hepatic steroid metabolism in trout.

Testicular atrophy produced by phthalate esters.

In a 90-day toxicity study in rats, di-(2-ethylhexyl)phthalate (DEHP) produced testicular atrophy. To characterise further the testicular toxicity of phthalate esters the effect of age on the induction of testicular atrophy has been examined as well as the reversibility of the lesions and the effects of certain other phthalate esters. Seminiferous tubular atrophy, comprising a loss of spermatids and spermatocytes, resulted when 4-week-old rats were given 10 daily doses of DEHP. In similarly treated 10-week old rats up to 50% of tubules were atrophic while the remainder were unaffected. No testicular damage was produced in 15 week-old rats. The lesion produced in 4-week-old rats was reversible whether treatment was stopped prior to, or continued until after the control rats had reached sexual maturity. Normal testicular weight and histology were restored within 12 and 20 weeks respectively. Of a series of di-n-alkyl phthalates from dimethyl to di-n-octyl, the butyl, pentyl and hexyl esters produced testicular lesions similar to DEHP. The testicular effects of DEHP were not influenced by simultaneous administration of testosterone or follicle stimulating hormone (FSH). The mechanism by which phthalate esters exert their effects is discussed in the context of a possible action on Sertoli cell function.

The influence of progestin and androgen on the fine structure of the male reproductive tract of the rat. I. General effects and observations on the testis.

The combination of a progestin and androgen has received attention as a possible male contraceptive. The progestin is thought to reduce gonadotropin release and suppress spermatogenesis, while the sex accessory organs and male characteristics are maintained by the simultaneous administration of testosterone. In the present study, the histology and ultrastructure of parts of the male reproductive tract of rats treated with medroxyprogesterone (Provera, Upjohn) (1 mg/100 g body weight/day) alone and combined with testosterone (15, 30, or 100 mug/100 g/day) were studied following treatment for up to 16 weeks. The testes and epididymides of rats administered Provera alone or Provera and testosterone weighed less than those of control rats. The weights of the accessory glands of rats treated with Provera were greatly reduced; it was possible to maintain them at approximately control levels by simultaneously administering sufficient testosterone (100 mug/100 g body weight/day). The fertility of some of the animals was tested by caging them with female rats, and none of the treated rats tested in this way was fertile. Similar microscopic alterations were present in the testes of animals administered Provera alone or Provera and different levels of testosterone. Spermatogonia, spermatocytes, and early spermatids were abundant in treated rats and did not show ultrastructural changes. However, many degenerating or necrotic spermatids of the cap phase (approximately stages 6-7) and later were present. Late spermatids of the acrosome and maturation phases were rare. Some necrotic spermatids were surrounded by Sertoli cells, and parts of spermatids lay within lysosome-lyke structures in the cytoplasm of Sertoli cells. Many large lipid droplets were also present in Sertoli cells of treated rats. Leydig cells were smaller in treated animals than in control rats. The results suggest that germ cells can develop up to cap phase spermatids but then undergo degeneration. These alterations in spermatogenesis may be responsible in large part for the antifertility effect of the progestin and androgen combination. Some rats were permitted to recover following the end of treatment. The microscopic appearance of the testis returned to normal within three to six weeks, although epididymal alterations persisted in some animals six weeks after the end of treatment. By 9 to 12 weeks after the end of treatment the reproductive organs had a normal microscopic appearance in all the rats studied.

Regulation of Lactogenic Hormone Binding in Rat Liver by Steroid Hormones

We have measured the effects of testosterone propionate, medroxy-progesterone acetate and cortisol on the binding of ovine [125I]iodoprolactin to 100,000 X g particulate fractions from liver of normal and estrogen-treated female rats. In untreated animals 6.7 +/- 1.1% (SD) of the radioactivity added to 0.5 mg of membrane protein was specifically bound to the hormone receptor. Specific binding was significantly (P less than .05) decreased after 7 daily doses of testosterone (1.0 mg) to 2.8 +/- 1.4%, medroxyprogesterone (0.25 mg) to 2.7 +/- 0.2% and cortisol (5.0 mg) to 3.1 +/- 1.3%. The serum prolactin concentration, 4.2 +/- 3.4 ng/ml in normal animals, was not affected by the hormone treatment. Ethinyl estradiol, 10 mug/day for 7 days, increasing the binding of [125I]iodo-prolactin to 16.6 +/- 6.0% and increased serum prolactin to 50.6 +/- 11.5 ng/ml. Simultaneous administration of testosterone, medroxyprogesterone or cortisol with estradiol did not diminish the estradiol-induced increase in serum prolactin, but completely prevented the increase in prolactin binding. Testosterone or cortisol given to animals pretreated with estradiol suppressed prolactin binding from 16.4 +/- 4.2% to less than 2.5% after 48-72 h. Parellel results were obtained with 125I labeled human growth hormone whereas 125I labeled-insulin binding was not affected by these treatments. Scatchard analysis showed that the decrease in lactogenic hormone binding was due to a reduced concentration of receptors with no significant change in affinity. Since serum levels of prolactin were not changed, we conclude that treatment with testosterone, medroxyprogesterone, and cortisol decreased lactogenic hormone binding by a direct action on the liver.

Effect of testosterone-estradiol administration on citric acid and fructose content of the rat prostate.

Implanatation of pellets of crystalline testosterone alone, in combination with estradiol pellets, or in combination with injections of 0.05 mg estradiol in sesame oil was carried out in 101 Sprague-Dawley rats orchiectomized 3 weeks. Rats from each group were autopsied at weekly intervals for 4 weeks. Body weight and the weight of the ventral, lateral and dorsal lobes of the prostate, the coagulating gland, and the seminal vesicles were noted. The citric acid content of the individual lobes of the prostate and the fructose content of the lateral and dorsal lobes of the prostate and the coagulating gland were determined. By the second week after pellet implantation, the simultaneous administration of testosterone and estradiol resulted in a much greater citric acid content and concentration in the lateral lobes of the prostate than did the administration of testosterone alone; an accompanying weight increase was also evident. No consistent effect on the citric acid or fructose content of the other lobes o...

A COMPARISON OF THE EFFECTS OF MALE AND FEMALE SEX HORMONES ON IMMATURE FEMALE RATS

ONE GAINS from the literature the impression of a possible antagonistic action between theelin and testosterone in certain instances. In mature ovariectomiz;ed mice Robson (1) found that the simultaneous administration of testosterone with estrone inhibited the estrous reaction of the vagina which was produced by estrone alone. Korenchevsky, Dennison and Hall (a) stated that the suppression of the cornifying effects of estrone, or of estradiol, by testosterone propionate may be considered as an antagonistic action in the rat. Wolfe and Hamilton (3) reported that the hypophysealenlargement and basophilic degranulation resulting from estrone therapy in the rat were negated by the addition of testosterone acetate. An inhibition of estrogenic effects on the skeleton of mice by testosterone propionate in′ jections was reported by Gardner and Pfeiffer (4). Zuckerman (5) produced a prostatic enlargement in rhesus monkeys by the administration of estrone, which was obviated by the addition of testosterone propionate

Inhibition of Oestrus and of the Vaginal Response to Oestrone by Testosterone

Mature mice showing regular oestrous cycles were injected with 0.1 mg. of testosterone in 0.1 cc. oil twice daily. (I am indebted to Messrs. Ciba, Limited, for the supply of testosterone.) During the period of injections extending over 2 weeks or more oestrus was abolished. Following cessation of injections oestrous cycles were reestablished. Injected mice were placed with males for a week; no mating was observed and no vaginal plugs were found. Normal cycles were continued in control mice injected with oil alone.Mature ovariectomized mice were injected with oestrone in doses sufficient to produce cornification, together with testosterone. The simultaneous administration of testosterone inhibited the oestrous reaction of the vagina. The oestrogenic effect of 0.0001 mg. of oestrone (a dose which produces cornification in 50% of our mice) was inhibited by 0.4 mg. of testosterone.These findings show that there may be a direct antagonism between the female and the male hormones in their actions on the vagina ...