Androgen-dependent fighting behaviour in male mice

The influence of testosterone propionate, 17 alpha-methyl-testosterone and cyproterone acetate on isolation induced fighting behaviour of mice was studied in a simple testing procedure. Decreased aggressiveness has been established in mature, sexual experienced and isolated male mice both following castration and administration of the antiandrogen cyproterone acetate, respectively. Replacement therapy with testosterone propionate s.c. and 17 alpha-methyl-testosterone p.o. has been shown to restore the decreased level of aggresiveness after castration.     

Effects of cyproterone acetate on mating behavior, testicular morphology, testosterone level, and body temperature in male ferrets in comparison with normal and castrated males

Effects of surgical castration of 60-day-old male ferrets are compared with the effects of a chemical castration with cyproterone acetate from postnatal day 60 until 360. Investigations were made on mating behavior, intermale aggression, testicular morphology, plasma testosterone level and body temperature. While controls show seasonal variations in all parameters, according to the annual cycle of sexual activity and inactivity, both, surgically and chemically castrated ferrets show throughout the year constant parameters similar to that of controls during the sexual inactive period. All investigated effects of a long-term treatment with cyproterone acetate are fully reversible within 2 years after termination of drug administration.     

Different behavior of the rat vas deferens of castrated animals and those treated with cyproterone acetate

The effects of castration and treatment with the antiandrogen cyproterone acetate (CPA) on the responses of the vas deferens of the rat induced by phenylephrine, KCl and BaCl2 has been studied. Both castration and CPA induced a spontaneous motility in the rat vas deferens. Castration produces a decrease of the response amplitude induced by phenylephrine and KCl and an increase of those induced by BaCl2 in animals killed 30 days after castration. CPA increases the response amplitude induced by phenylephrine and KCl without modifying those induced by BaCl2. These results suggest that the antiandrogen CPA produces modifications qualitatively different from castration.     

Effect of antiandrogen cyproterone acetate on the action of testosterone on mouse kidney.

The loss of endogenous testosterone in castrated male mice leads to a marked decrease in seminal vesicle and kidney tissue weight. 21 days' administration of exogenous testosterone abolished the effect of castration on the seminal vesicles and kidney tissue. The antiandrogen cyproterone acetate produced significant changes in the target tissue for androgens, i.e. in the seminal vesicles. In every case it blocked the action of both exogenous and endogenous testosterone on the seminal vesicles, but failed to block the "renotropic" action of testosterone, expressed as relative kidney weight. Contrary to its effect on the seminal vesicles, it did not influence relative kidney weight in normal animals. It likewise did not block the effect of exogenous testosterone on kidney tissue. The mechanism of the action of cyproterone acetate in androgen-dependent tissues is known to consist in inhibition of androgen binding to specific cell receptors in the target tissues. Some of the specific androgen receptors in mouse kidney are evidently different in character from those in the accessary sex glands, that being the reason why cyproterone acetate has an antiandrogenic, but not an antirenotropic effect. In agreement with experiments on rats, adrenal weight also decreases in mice after the administration of cyproterone acetate.     

Short-term effect of androgen deprivation on intraluminal pressure and contractility of the rat epididymis

Short-term effects of bilateral castration, cyproterone acetate and unilateral efferent duct ligation on intraluminal pressures and spontaneous contractions in different regions of the epididymis were studied in the rat. Ligation of the efferent ducts for 5 days did not alter pressures or spontaneous contractions in any region of the epididymis. However, bilateral castration produced time-dependent changes in pressures and contractions in different segments. In the caput, the amplitude, but not the basal pressure or the frequency, of spontaneous contractions increased by Day 1 after operation. In the corpus, increments in the basal pressure and the amplitude of contractions occurred by Day 5 whilst the frequency of contractions was not changed. Similar effects were observed in the cauda by 3 days after castration. Changes in all regions of the epididymis were also mimicked by cyproterone acetate treatment (10 mg/rat per day, s.c. for 21 days). In addition, this drug increased the amplitude of contractions in the cauda. The effect of castration was abolished by testosterone propionate (0.2 mg/kg per day, i.m. for 5 days). The results support the suggestion that an enhancement of sperm transport through the rat epididymis occurs shortly after castration. The results also suggest that, in normal rats, androgens suppress the contractility of the epididymal tubule to ensure an optimal rate of sperm transport.     

The fine structure of the rat pineal and the influence of anti-androgens and castroation]

The pineal body, along with the hypothalamus-hypophysis system, is in the centre of sexual hormone regulation and, in addition to other functions, develops an antigonadotropic action through its organ specific hormone (melatonin). In order to clarify further open questions and to analyse more closely the morphology of the fine structure of the organ, light and electron microscopic studies were made of the pineal bodies of sexually mature male rats after hormonal castration by the administration of cyproterone and cyproterone acetate. The findings were compared with results obtained in the pineal bodies of surgically castrated animals of the same strain. Epiphysectomy was performed 3, 6, 9 and 12 weeks after castration or application of antiandrogen. In the pineal bodies, "light" and "dark" pineal cells and an interstitial cell form could be detected electronmicroscopically. The interstitial cells are found localised near the vessels in particular; their ramifications reach into the perivascular cleft. The light pineal cells preponderate and react essentially in the series; they are therefore considered as the really active form of parenchyma cells. Increased cell activity is already observed three weeks after treatment with antiandrogen: the nucleoli are enlarged, the ribosomes, the mitochondria and ergastoplasm are increased, the endoplasmic reticulum quantified and extended, and also the Golgi regions. The cells are consequently enlarged. Lysosomes also appear which frequently enter the liposomes. The changes in the liposomes after application of antiandrogen are remarkable. Initially they are evacuated, partially drawn out. Later the liposomes are enlarged and increased and often fill the cell body. These pineocytes form an appendage to the castration cells of the hypophysis. The liposomes are in a very close spatial, formal genetic relationship to the Golgi apparatus and to the rough walled reticulum. The larger liposomes apparently arise also through the confluence of smaller ones. Three structural elements of the liposomes could be indentifed: a homogenous, a lamellar and a granular component. The fine morphological reactions are most marked after cyproterone acetate. For the first time, bundles of "microtubuli" are described, the significance of which is not yet clear. They probably arise from the endoplasmic reticulum, they are only found after cyproterone acetate and are presumably due to the gestagen component of the cyproterone acetate. These structures have not previously been observed, either in pineal bodies or in other organs. The structures found after antiandrogen are not so outstandingly recognisable after surgical castration. The biological differences of the surgical compared with hormonal castration therefore seem to be reflected in the cell picture of the pineocytes. Consequently, the pineal body, after treatment with antiandrogen, shows cytostructural changes similar to those of increased anabolism...     

Effect of cyproterone acetate on the pregnancy-blocking ability of male mice and the possible chemical nature of the pheromone

Even though castration abolished the ability of alien males to induce implantation failure (the Bruce effect) in newly inseminated females, treatment of intact alien males with the steroidal antiandrogen, cyproterone acetate, for 14 days (short term) did not significantly depress their ability to induce the Bruce effect. However, prolonged treatment (42 days) with cyproterone acetate suppressed the pregnancy-blocking ability of alien males to some extent, possibly due to the antigonadotrophic properties of the drug. Ovariectomized alien females treated with implants of testosterone (androgenized females) exhibited the ability to block implantation in newly inseminated females, but concurrent treatment of androgenized females with cyproterone acetate did not depress this ability. The results strongly suggest that the pheromone involved in the male-induced implantation failure is not the product of an androgen-dependent tissue, but is likely to be a product of androgen metabolism.     

Autoradiographische Untersuchungen zur Mitoseaktivität im Hypophysenvorderlappen männlicher Ratten nach Behandlung mit Antiandrogenen und nach Kastration

Zusammenfassung Nach Applikation von ³H-Thymidin wird die Mitoserate im Hypophysenvorderlappen von männlichen Ratten nach 10-bzw. 14tägiger Behandlung mit Antiandrogenen (Cyproteron bzw. Cyproteronacetat) und 10 bzw. 14 Tage nach Kastration autoradiographisch untersucht. Kastrierte oder Cyproteron-behandelte Tiere weisen gegenüber Normaltieren eine 3–4fach erhöhte Zahl markierter HVL-Zellen auf. Nach Behandlung mit Cyproteronacetat ist dagegen die Mitoserate vermindert. — Die Ergebnisse ergänzen die Vorstellung vom Wirkungsmechanismus der genannten Antiandrogene, wonach Cyproteron nur antiandrogen wirkt und damit die FSH-Abgabe im HVL erhöht, wogegen Cyproteronacetat zusätzlich antigonadotrope Wirkung besitzt, die die FSH-Abgabe drosselt.

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Radioautographic investigations on the rate of mitosis in the anterior pituitary in male rats after treatment with antiandrogenic substances and castration

Summary After application of ³H-thymidine the rate of mitosis in the anterior pituitary of male rats is investigated by means of radioautography after treatment with antiandrogenic substances (cyproterone and cyproterone acetate) for 10 and 14 days respectively and 10 and 14 days after castration. Castrated or cyproterone-treated rats show a 3 to 4 fold increase of the number of labeled anterior pituitary cells as compared to untreated animals. In the anterior pituitary of cyproterone acetate-treated rats the rate of mitosis decreases. — The present results are in accordance with the view, that cyproterone acts only antiandrogenic and stimulates the FSH-release in the anterior pituitary, whereas cyproterone acetate has also an antigonadotrophic effect, which slows down the FSH-release.

Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Influence of sex hormones on ethanol-induced gastric haemorrhagic erosions in rats.

The role of sex hormones in the pathogenesis of ethanol-induced gastric erosions was investigated following the recent observation that ethanol generates more severe gastric damage in male rats. Female and male Wistar rats aged 110 +/- 6 days were used. Intact female, ovariectomized female, intact male, orchidectomized male and cyproterone acetate-pretreated (this compound a testosterone antagonist) male rats were investigated. 1 ml of 75% ethanol was used to induce gastric lesions. The extent of the erosions was determined planimetrically 60 min after ethanol administration. The plasma testosterone and 17-beta-oestradiol levels were checked by radioimmunoassay (RIA) in gonadectomized rats. Ethanol generates more severe lesions in male rats. Orchidectomy and cyproterone acetate treatment each reduced the extent of ethanol-induced gastric erosions in male rats. Ovariectomy had no effect in this model. The plasma testosterone and 17-beta-oestradiol levels were significantly reduced after gonadectomy. It is concluded that endogenous testosterone plays an aggressive role in the pathogenesis of ethanol-induced gastric erosions in rats.     

Influence of chlormadinone acetate on hypothalamic differentiation in male rats

The effect of chlormadinone acetate on adult male rats during the hypothalamic differentiation phase was studied. Psychic intersexuality with increased male and increased female sexual behavior was observed both before and after postpuberal castration and sex hormone replacement. Organ weights of testes, seminal vesicles, and ventral prostrates were normal, but penis and adrenal gland weights were significantly smaller. Body growth was also significantly reduced compared with control animals. The effects of chlormadinone acetate on androgen-dependent brain differentiation are discussed and compared with analogous effects of cyproterone acetate and orchidectomy.     

Further regression of seminal vesicles of castrated guinea pig by administration of cyproterone acetate

It has been established that a low level of secretory activity persisted in seminal vesicles of guinea pigs long after castration and that this may be due to a higher extratesticular androgen level in this animal. A RIA study revealed that the normal serum testosterone concentration of the guinea pigs was comparable to that of the rats, but the basal serum testosterone level after castration was ten times higher than rats under a similar condition. It was also shown that cyproterone acetate did not significantly lower the basal serum testosterone concentration in the castrated guinea pigs. The higher basal serum testosterone level is believed to be responsible for the slow and incomplete regression of this gland in the guinea pigs. There was a significant reduction in wet weight of the seminal vesicles after the treatment of castrated guinea pigs with cyproterone acetate. Ultrastructural study showed that there were both qualitative and quantitative changes in the cytoplasmic organelles. The Golgi apparatus further reduced in size and in the number of associated vesicles and vacuoles. There was a marked decrease in the number and size of secretory granules and lysosomes and an increase in the degree of undulation of the basement membrane. Accumulation of lipid droplets and glycogen was commonly observed. All these morphological evidences showed that further regression of the castrated guinea pig seminal vesicles can be achieved by cyproterone acetate treatment.     

Effects of castration on thiol status in rat spermatozoa and epididymal fluid

Mammalian spermatozoa gain their fertilizing ability as they mature in the epididymis, a process which is accompanied by oxidation of sperm protein thiols. Since sperm maturation is dependent upon normal androgenic support to the epididymis, the present work was designed to study the effects of castration on thiol status. Spermatozoa and epididymal fluid were isolated from the epididymides of male rats 5 days after castration or after 11 daily injections of the antiandrogen, cyproterone acetate. Spermatozoa and epididymal fluid were labeled with the fluorescent thiol labeling agent monobromobimane. Intact spermatozoa were evaluated by fluorescence microscopy, protein thiols were analyzed by electrophoresis, and fertilizing ability was examined after insemination of sperm suspension into the uterine horns of immature superovulated female rats. We found that both treatments resulted in an increase in cauda sperm thiols as shown by increased fluorescence in the intact spermatozoa. Protamines and nonbasic proteins were found to have increased levels of reactive thiols. The protein profiles of epididymal fluid from castrated rats were different from those of the controls, and the fluorescence patterns corresponded to the protein profiles. Our results indicate that testosterone withdrawal leads to inhibition of sperm thiol oxidation. Mol. Reprod. Dev. 47:295–301, 1997. © 1997 Wiley-Liss, Inc.     

Glucocorticoid induction of hepatic alpha2u-globulin synthesis and messenger RNA level in castrated male rats in vivo.

alpha2u-Globulin is a male rat liver protein of Mr = 20,000 which is synthesized in the liver of adult male rats, secreted into the serum, and excreted in the urine. Its function is unknown. The hepatic synthesis of this protein is under complex hormonal control. We had previously shown that castration of male rats diminishes hepatic alpha2u-globulin synthesis and the level of its mRNA, and that administration of androgen to these castrated animals results in the reinduction of the synthesis of this protein and the level of its mRNA. We now report that alpha2u-globulin synthesis and the level of its mRNA can be fully reinduced in castrated males by administration of glucocorticoid alone. This induction is much more rapid than the androgenic induction and is inhibited by the glucocorticoid antagonist progesterone. Administration of glucocorticoid to intact male animals does not induce alpha2u-globulin synthesis above normal levels; however, if alpha2u-globulin synthesis has been depressed in intact male rats by pretreatment with estrogen or cyproterone acetate, the level of this protein can be reinduced by administration of glucocorticoids. The implications for the control of alpha2u-globulin gene expression are discussed.     

Androgen metabolism by rat epididymis. 3. Effect of castration and anti-androgens.

The in vivo and in vitro metabolism of 3H-testosterone by rat epididymis and the changes in epididymal weight have been studied after castration and treatment with anti-androgens. The utilization of 3H-testosterone was greatly reduced after castration as was the formation of 5alpha-reduced 17 beta-hydroxy metabolites. The formation of the 17 -keto metabolites was unaffected. Castration had no effect on the ratio between water and ether soluble radioactivity. Administration of testosterone propionate, necessary for giving normal stimulated prostate weight (150 mug/day), restored the metabolism of testosterone to approximately normal values. Estradiol benzoate and progesterone inhibited metabolism of testosterone in vitro and greatly reduced the formation of DHT (17 beta-hydroxy-5alpha-androstan-3-one) and 3 alpha-diol(5 alpha-androstane-3 alpha-17 beta-diol) by experiments both in vivo and in vitro. No effect of cyproterone acetate could be demonstrated on either the in vitro or in vivo metabolism of testosterone. Castration for 14 days reduced the epididymal weight to about 30% of that found in intact animals. Administration of testosterone propionate restored the epididymal weight to about 80% of normal. Estradiol benzoate and cyproterone acetate given to intact rats led to a decrease in the epididymal weight. Progesterone had no such effect. In 14 days castrated rats receiving testosterone propionate all three anti-androgens reduced the weight of the epididymis. In conclusion, our results show that the metabolic conversion of testosterone in epididymis to DHT and 3 alpha-diol is dramatically dependent on the hormonal status of the animal; castration or treatment with anti-androgens causes a reduced formation of the "active" androgens whilst testosterone replacement treatment restores the metabolism of testosterone to normal.     

Ultrastructural evidence for endogenous testosterone immunoreactivity in the pituitary gland of the rat

Summary Several attempts have been made to localize steroids by means of immunocytological techniques. However, these methods were found inadequate for detecting steroids bound to their receptors. To localize endogenous testosterone (T) in its target cells at the ultrastructural level, an immunocytological technique was performed on ultrathin sections obtained by cryo-ultramicrotomy. T was detected in the pituitary glands obtained from intact male or female rats and castrated rats, but not in castrated + adrenalectomized rats. Animals were also injected either with testosterone, with other steroids (estradiol, progesterone, corticosterone) or with an androgen antagonist (cyproterone acetate). In addition, some ultrathin sections were preincubated either with phosphate buffers of various pH, corticosterone, cyproterone acetate solution, or with T solution. The content of T in the pituitary before and after fixation was measured by radioimmunoassay; it decreased after fixation. T immunoreactivity was localized in the gonadotropic cells only, both in the male and female rats. At the subcellular level, the immunoreactivity was detected in the cytoplasmic matrix and in the nucleus. Immunoreactive T disappeared 1) in rats after castration+adrenalectomy; by means of radioimmunoassay no T was measured in these pituitary glands; 2) in rats injected with 25 (g/rat of cyproterone acetate; 3) after preincubation of pituitary sections on a drop of cyproterone acetate (1 × 10^-6 M). The immunocytological reaction was not modified when the rats were injected with estradiol, progesterone or corticosterone (1 mg/rat), or after preincubation of the sections with corticosterone (1 × 10^-3 M), or a buffer solution at pH 7.6. Lower or higher pH values led to a strong decrease in the immunoreactivity. After injection of T (15 g/rat) the immunocytological reaction was more abundant in the nucleus and less in the cytoplasm. The immunoreactivity was again observed when the sections were preincubated with cyproterone acetate solution and then with T solution. These data suggest that T can be detected by means of immunocytochemistry. It is probably bound to a specific binding site.This work was presented in part at the VI^th International Congress on Hormonal Steroids, Jerusalem, 1982     

Pharmacology of an antiandrogen, anandron, used as an adjuvant therapy in the treatment of prostate cancer

To improve the inhibition of prostate cancer growth obtained by surgical or chemical castration (estrogens or LHRH analogs), blockade of the action of residual androgens of adrenal origin has been proposed. Among antiandrogens acting through the androgen receptor (AR), the nonsteroid anandron (RU 23908) has several advantages over available compounds: megestrol acetate and cyproterone acetate, both steroids, bind substantially to other hormone receptors (progestin, gluco- and mineralocorticoid); and anandron binds only to AR. The nonsteroid flutamide is a prodrug converted to the active metabolite, hydroxyflutamide; anandron is well absorbed on oral administration of an active dose and intact compound disappears slowly from plasma. This may explain why, although in vitro anandron interacts very transiently with AR, in vivo a high level of untransformed anandron is present at the receptor site to induce its antiandrogenic activity. Animal experiments confirm that anandron can counteract the effect of adrenal androgens and inhibit the LHRH analog-induced initial increase in androgen ("flare-up"). Thus, in rats castrated either surgically or by buserelin or DES and supplemented with adrenal androgens (since endogenous adrenal secretion is very low in this species compared to man), anandron decreased prostate weight to control levels. The administration of buserelin to intact rats over 15 days resulted in a significant increase in prostate weight between Days 1 and 5. The addition of anandron to the buserelin inhibited this increase and, furthermore, led to a far greater decrease in prostate weight than that due to buserelin alone at 15 days, indicating a synergy of action.     

The effect of artificial photoperiodicity and antiandrogen treatment on the antler growth and plasma levels of LH, FSH, testosterone, prolactin and alkaline phosphatase in the male white-tailed deer

1. Artificial extension of day-length in adult male white-tailed deer during the autumn induced: (a) premature casting of antlers, early onset of the new antler growth and out of season mineralization, (b) early elevation of plasma levels of prolactin, LH, FSH, testosterone and alkaline phosphatase and (c) out of season hair molt. 2. Intramuscular administration of the antiandrogen cyproterone acetate immediately after velvet shedding induced: (a) dramatic reduction of testosterone levels in plasma, (b) premature casting in bucks with fully mineralized antlers and (c) renewal of bone rebuilding activity in incompletely mineralized antlers which resulted in blockage of casting.     

Androgen-dependence of ornithine decarboxylase in the rat epididymis

Ornithine decarboxylase (ODC) activity was measured in epididymides of 45-day-old rats. Higher ODC activity was detected in the corpus and cauda than in the caput epididymidis. Bilateral castration for 7 days caused epididymal ODC to fall to undetectable values, whereas testosterone restored activity to normal values. The effect of the androgen was significantly inhibited by cyproterone acetate. The caput was more sensitive to the action of testosterone than were the corpus and caudal segments. Unilateral castration for 4 or 8 days did not affect ODC on the control or castrated side, but the activity fell in epididymides of both sides after removal of the remaining testis. These results show that epididymal ODC activity is androgen-dependent.     

Effects of the antiandrogens cyproterone acetate and flutamide on male reproductive behavior in a lizard (Anolis sagrei)

This study examined the effects of the antiandrogens cyproterone acetate (CA) and flutamide (F) on male reproductive behavior in the lizard Anolis sagrei. Reproductively active males were implanted with subcutaneous pellets of either CA, F, or placebo (P). Pellets delivered CA and F at a constant rate of 0.1 mg/day. Three weeks after implantation, males were tested with stimulus males and two days later with stimulus females. Cyproterone acetate inhibited aspects of male aggressive and sexual behavior, and reduced testis weight and size of the renal sex segment. Plasma testosterone (T) levels in CA-treated males were not significantly different than those of P-treated males. Flutamide did not inhibit aggressive or sexual behavior, but did decrease testis weight as well as the size of the renal sex segment. Plasma T levels were significantly higher in F-treated males than in P-treated males. These data suggest that CA, an antiandrogen with antigonadotropic activity, may be used to inhibit reproductive behavior in male lizards.     

Ultrastructural and functional characteristics of anterior pituitary cells in the Indian fruit bat, Rousettus leschenaulti (Desmarest)

The pituitary glands of normal and experimental male and female bats were examined by light and electron microscopy. Six cell types were identified in the anterior pituitary by differential staining techniques, ultrastructural characteristics and changes brought about during the different phases of the sexual cycle. Conventional methods like removal of thyroids, testes and adrenals, and animals in lactation withdrawal and treatment with propylthio-uracil, cyproterone acetate and metyrapone were employed. A marked predominance of somatotrophin and luteotrophin (LTH) cells were present in the intact adult female bat pituitary gland. LTH cells were also observed in milk retention experiments. The two gonadotrophic cell types were randomly distributed throughout the gland. Hypertrophy of two gonadotroph cells was observed in response to the physiological conditions of the animals, gonadectomy and administration of the male antifertility drug cyproterone acetate. Thyrotrophin and adrenocorticotrophin cells were identified by ablation of the respective target organs, thyroids and adrenals, and after treatment with propylthio-uracil and metyrapone. On the basis of the pathological conditions of the bats, the possible functional significance of the different cell types is also discussed.