Comparison of the effects of cyproterone, cyproterone acetate and oestradiol on testicular function, accessory sexual glands and fertility in a long-term study on rats

The influence of pharmaceutical compounds on male fertility

1. Steroid hormones can affect spermatogenesis and thereby fertility directly and/or indirectly. All antigonadotropically active steroids inhibit spermatogenesis via inhibition of gonadotropin secretion, mainly that of H. Androgens and steroids occurring in the biosynthetic chain of testosterone synthesis have a direct promoting effect on spermatogenesis if applied in high doses. It has not been possible as yet to make clinical use of this positive effect since it is obviously not possible to achieve the necessary intratesticular androgen concentrations. 2. As concerns the different androgens and the steroids in the androgen biosynthetic chain, and also all synthetic anabolics, there is no parallelism between the direct spermatogenic activity, the androgenic activity and the antigonadotropic activity. 3. Estrogens and synthetic gestagens do not inhibit spermatogenesis directly at the testicular level. All effects of estrogens can be abolished experimentally by adequate substitution with gonadotropins or androgens, or a combination of androgens and gonadotropins. 4. Only those antiandrogens inhibit spermatogenesis with additional antigonadotropic properties (e.g. cyproterone acetate). Pure antiandrogens, like flutamide or cyproterone, have a slight and transient influence on spermatogenesis at the most. If at all, they merely cause transient subfertility. 5. Beside steroids and several centrally active pharmaceutics (e.g. psychotropic drugs and several antihypertensive compounds), only siloxanes and methallibur seem to affect spermatogenesis via inhibition of gonadotropin secretion. Other antispermatogenic agents act by inhibition of mitosis (Colchicine, alkylating agents) or presumably via damage of the Sertoli cells. 6. Based on present knowledge, contraception in men could be principally managed by administration of a) androgens alone, b) gestagen/androgen combinations, c) estrogen/androgen combinations, d) certain antiandrogens. 7. The difficulties of contraception in men by steroid hormones or steroid hormone combinations have been pointed out. As regards the usefulness of antiandrogens for contraception, no definite conclusions can be drawn at the moment. All non-steroidal inhibitors of spermatogenesis which have been found up to the present are not suitable because of toxic effects.

Short-term antiandrogen flutamide treatment causes structural alterations in somatic cells associated with premature detachment of spermatids in the testis of pubertal and adult guinea pigs

In spite of widespread application of flutamide in the endocrine therapies of young and adult patients, the side effects of this antiandrogen on spermatogenesis and germ-cell morphology remain unclear. This study evaluates the short-term androgen blockage effect induced by the administration of flutamide to the testes of pubertal (30-day old) and adult (65- and 135-day old) guinea pigs, with an emphasis on ultrastructural alterations of main cell types. The testes removed after 10 days of treatment with either a non-steroidal antiandrogen, flutamide (10 mg/kg of body weight) or a pharmacological vehicle alone were processed for histological, quantitative and ultrastructural analysis. In pubertal animals, flutamide androgenic blockage induces spermatogonial differentiation and accelerates testes maturation, causing degeneration and detachment of primary spermatocytes and round spermatids, which are subsequently found in great quantities in the epididymis caput. In post-pubertal and adult guinea pigs, in addition to causing germ-cell degeneration, especially in primary spermatocytes, and leading to the premature detachment of spherical spermatids, the antiandrogen treatment increased the relative volume of Leydig cells. In addition, ultrastructural evaluation indicated that irrespective of age antiandrogen treatment causes an increase in frequency of organelles involved with steroid hormone synthesis in the Leydig cells and a dramatic accumulation of myelin figures in their cytoplasm and, to a larger degree, in Sertoli cells. In conclusion, the transient exposition of the guinea pigs to flutamide, at all postnatal ages causes some degenerative lesions including severe premature detachment of spermatids and accumulation of myelin bodies in Leydig and Sertoli cells, compromising, at least temporarily, the spermatogenesis.

Effects of cyproterone acetate and testosterone treatments on some physical parameters, angiotensin converting enzyme activity and fertilizing ability of spermatozoa of domestic cocks (Gallus domesticus)

Healthy adult cocks were administered through the intramuscular route with 1 or 15 mg cyproterone acetate (CyA)/kg b. wt. or testosterone at the rate of 1.5 mg/kg b. wt. daily for a period of 25 days. High doses of CyA and testosterone caused severe suppression (P less than 0.01) of semen volume, sperm concentration, sperm motility and angiotensin converting enzyme activity (ACE EC 3.4.15.1). Fertilizing ability of spermatozoa was also reduced drastically at the end of treatment period. No loss of sexual behaviour was observed in treated birds as compared to controls. Recovery in all parameters from deleterious effects of these drugs was rapid after cessation of treatment. Lower doses of CyA did not affect the parameters of semen. The results are discussed in relation to the possible mechanism of action of CyA and testosterone.

Effects of cyproterone acetate and flutamide on the testis and epididymis of the Indian wall lizard, Hemidactylus flaviviridis (Ruppell)

Intramuscular injections of 0.2 mg cyproterone acetate (CA) or flutamide every other day for 6 weeks resulted in the inhibition of spermatogenesis. While CA treatment reduced the weight of the testis significantly, flutamide did not. Inhibition of steroidogenesis, indicated by an accumulation of sudanophilic lipid and a decrease in delta 5-3 beta-hydroxysteroid dehydrogenase and glucose-6-phosphate dehydrogenase activity, was evident in the Leydig cells of CA-treated testis. Flutamide, on the other hand, had no effect on the activity of Leydig cells. A marked decline in epididymal weight, as well as reduction in epithelial cell height, was caused by both CA and flutamide. The epithelial cells of epididymes of treated lizards exhibited an accumulation of sudanophilic lipid material in their cytoplasm. However, sudanophilic secretions present in the lumina of epididymal tubules were greatly reduced. This indicates either lack of synthesis of lipid or decrease in its turn over. Our results are in agreement with those obtained in mammalian species after CA or flutamide treatment where a decrease in fertility is suggested.

Lectin staining of rat testis and epididymis: effect of cyproterone acetate and testosterone

Control and castrated (C) adult rats were treated with cyproterone acetate (CA), testosterone (T) or their combination (CA + T) for 15 days and the affinity of the testicular and epididymal tissue for seven rhodamine-conjugated lectins was analysed in fluorescence microscopy. In the testis CA caused the appearance of degenerating cells in the basal part of the seminiferous epithelium. These cells (spermatogonia, early spermatocytes) appear to be the most vulnerable germinal cells to anti-androgen treatment and this effect could be prevented by simultaneous administration of T. Castration caused a marked reduction in lectin staining of principal and light cells of distal caput (Dcp) and distal cauda (Dcd) epididymidis accompanied by the disappearance of the intratubular sperm mass. In castrated animals CA caused a moderate and T as well as CA + T a marked increase in the stainability of these cells and the appearance of homogeneous secretory material in the tubules. This material gave moderate or strong affinity for most of the lectins. Some minor differences were found in the staining pattern of the cells and the secretory material in Dcp and Dcd as well as after different treatments. This is consistent with local and qualitative differences in the epididymal secretory and absorptive activity, which can be further modified by the hormonal milieu.

Estrogen and accessory sex gland lipids

Administration of estradiol-17 beta elicited differential responses on accessory sex glands of rats. In caput epididymis, the estrogen treatment led to an accumulation of glycerides and phospholipids while in cauda epididymis, there was no significant change. However, in seminal vesicles, depletion of phospholipids was observed. In prostate, the treatment, resulted in an accumulation of glycerides.

Effects of cyproterone acetate with combination of testosterone enanthate on seminal characteristics, androgenicity and clinical chemistry in langur monkey

Daily oral administration of 1 mg/kg b.w. of cyproterone acetate and simultaneously administered testosterone enanthate (2 mg/kg b.w./15 days; i.m.) to adult male langur monkeys over a period of 90 days caused a gradual decrease in the count (to azoospermia) and motility of spermatozoa, concurrently with an increase in the percentage of non-motile as well as abnormal and immature sperm. Semen weight, volume, seminal fluid volume and circulating testosterone levels decreased nonsignificantly. Semen pH, libido and body weight remained unimpaired. The levels of SGOT, SGPT, serum alkaline phosphatase, LDH, bilirubin, Na+, K+ and hematological values did not alter significantly. All the changes were reversible. The results indicate that the combination regimen seems to affect the fertility in two ways, i.e. by inhibiting spermatogenesis in the testis and maturation process in the epididymis without altering the androgenicity.

The effect of estrogen administration in vivo on the elemental composition of the intraluminal fluids of the seminiferous tubules, rete testis, and epididymis of the rat

The maturation of spermatozoa in the epididymis is dependent upon the presence of androgens. This study examined the effects of androgen suppression by estradiol valerate on the elemental composition of the intraluminal fluids of the testis and epididymis. In the fluid from the caput epididymidis, the concentrations of sodium (106.1 +/- 3.4 to 182.8 +/- 16.9 mmol/1, P less than 0.01) and chloride (16.5 +/- 2.2 to 79.3 +/- 10.8 mmol/1, P less than 0.01) rose after treatment with estradiol valerate. By contrast, this treatment reduced the concentrations of phosphorus (63.7 +/- 1.6 to 47.8 +/- 3.2 mmol/1, P less than 0.01), sulfur (18.4 +/- 1.0 to 10.8 +/- 1.0 mmol/1, P less than 0.01), calcium (0.93 +/- 0.09 to 0.50 +/- 0.07 mmol/1, P less than 0.01), and magnesium (2.21 +/- 0.41 to 0.76 +/- 0.16 mmol/1, P less than 0.01). In the distal cauda epididymidis, the concentration of chloride rose after treatment with estradiol valerate (24.4 +/- 1.7 to 54.9 +/- 3.9 mmol/1, P less than 0.01), but the concentrations of the other measured elements (sodium, potassium, phosphorus, calcium, magnesium, and sulfur) were not altered by estrogen treatment. In rete testis fluid the concentration of phosphorus fell (2.00 +/- 0.30 to 0.67 +/- 0.12 mmol/1, P less than 0.01), while that of calcium rose (0.66 +/- 0.15 to 1.55 +/- 0.21 mmol/1, P less than 0.01). Estrogen treatment did not appear to affect the elemental composition of seminiferous tubular fluid or serum. Therefore, estradiol valerate had a marked impact on the elemental composition of luminal fluid only in the caput epididymidis--where sperm maturation is initiated--and a minor effect on that of cauda epididymidal fluid--in which mature spermatozoa are stored.

Effect of chronic use of cyproterone Acetate on the epididymis of goat

Effect of chronic treatment of cyproterone acetate, and antiandrogen with antigonadotrophin activity, on the epididymal sperm reserve and sperm maturation was studied in Black Bengal goats (a dwarf breed). It was observed that this compound produced significant reduction in epididymal sperm numbers in the treated groups as compared to the controls. There was significant reduction in progressive sperm motility. Other morphological maturation changes like the length and breath of the sperm head were significantly altered after treatment with CA for 70 days; and greater number of caudal spermatozoa of treated animals retained their cytoplasmic droplets than those of controls.

Estradiol-17 beta inhibition of androgen uptake, metabolism and binding in epididymis of adult male rats in vivo: a comparison with cyproterone acetate

The effects of estradiol-17 beta on androgen uptake, metabolism and binding were studied in rat epididymis in vivo in comparison with cyproterone acetate. Steroids (250 ug/100 g body weight) were injected 5 min prior to 3H-testosterone in castrate rats. Estradiol-17 beta inhibited 3H-testosterone uptake into epididymal cytosol by 58% as compared to 38% by cyproterone acetate. 3H-Testosterone uptake into epididymal nuclei was inhibited 95% by estradiol-17 beta and 83% by cyproterone acetate. Total bound radioactivity in cytosol fractions was reduced to a greater extent by estradiol-17 beta than cyproterone acetate when either 3H-testosterone or 3H-dihydrotestosterone was injected. Binding of 3H-dihydrotestosterone to nuclear receptors was completely abolished by estradiol-17 beta; whereas approximately 20% binding remained in the nuclear extract after cyproterone acetate treatment. Metabolism of 3H-testosterone in vivo was also altered by estradiol-17 beta, resulting in diminished conversion to 3H-dihydrotestosterone. Cyproterone acetate, on the other hand, did not affect 3H-testosterone metabolism. Estradiol-17 beta and cyproterone acetate inhibited in vitro binding of 3H-dihydrotestosterone to the intracellular cytoplasmic receptor, but not the intraluminal androgen binding protein (ABP). These data suggest that estradiol-17 beta may have a more potent antiandrogenic effect on the epididymis than cyproterone acetate due to inhibition of 5 alpha reduction of testosterone as well as binding to the androgen receptor.

Immunological sterilization of male dogs by BCG

The effect of a single intratesticular injection of Freund's complete adjuvant (FCA), incomplete Freund's adjuvant (IFA) and various components has been investigated in dogs. FCA caused severe granulomatous reaction with wide-spread degeneration and vacuolation of the tubules. IFA and Arlacel A induced oligo - but not azoospermia, which was of short duration (6 weeks). Bacillus Calmette Guerin (BCG) suspended in saline given with uniform distribution at doses of 10 units or higher was effective in inducing aspermatogenesis. The sperm count declined to near zero level within 3 to 6 weeks after injection of BCG, and sperm suppression was maintained for 6 to 11 months of the observation period. At moderate doses of 10 to 25 units partial to complete inhibition of spermatogenesis was seen in different tubules with leukocyte infiltration in the interstitium. The basement membrane of the tubules, the peritubular cells as well as the Leydig cells were intact. At high doses (75-110 units) and at sites where bacillary deposits were high even in moderate dose animals, there was massive leukocyte infiltration with nonspecific damage to the tubules. The animals, on low or high dose, retained libido and copulated with bitches in oestrus. The mating was, however, infertile. The treatment, especially with low and moderate doses, was largely free of significant side effects. At higher doses, scrotal pain and swelling lasting for 7-15 days was observed; a small decrease in the size of the testes was also noted.

Morphological pattern elicited by agents affecting spermatogenesis by stimulation

A variety of agents (clomiphene citrate, cyproterone acetate, estradiol 17-beta, medrogestone, medroxyprogesterone, and methoxychlor) thought to disrupt the normal pathway by which hormones stimulate the testis were tested in rats to determine the early morphologic changes in the testis. After initial trial experiments at which dose and sacrifice intervals were determined, the earliest morphological abnormalities were assessed quantitatively and related to the particular spermatogenic stage in which these defects were initiated. All agents tested produced an identical morphological pattern of response displaying a significant increase in Stage VII degenerating cells (pachytene spermatocytes, step 7 and step 19 spermatids) as compared with vehicle-administered rats. The number of degenerating cells in other stages did not significantly change. The rise in degenerating cells in Stage VII, as seen in this study, was similar to that reported in Russell and Clermont (1972) utilizing hypophysectomized rats, and that reported by other investigators who have used a variety of agents to disrupt the hormonal stimulation of the seminiferous tubules. The data indicate that no matter how, or at what level the hormonal stimulation of the testis is interrupted, the morphological pattern of response is the same, and that such a pattern is useful in predicting the mechanism of action of agents suspected of interfering with hormone action.

Cyproterone acetate and seminal vesicles in the regulation of male fertility

The effect of continuous release of microquantities of cyproterone acetate from subcutaneously implanted silastic capsules on the fertility of surgically manipulated seminal vesicles of rat has been studied. The experimental animals showed infertility for 3 weeks, as a consequence of removal of seminal plasma, following which normal fertility returns as efficiently as that operated control. However, a significant decrease in weight of the testes and epididymides, were recorded. It appears that seminal vesicles can synthesize seminal plasma even at very low levels of androgen in the presence of cyproterone acetate.

Effect of castor oil and benzyl benzoate used as a vehicle for antiandrogens on the adrenal cortex

The use of benzyl benzoate as a vehicle constituent in administering cyproterone acetate caused morphological changes detectable at the ultrastructural level in the adrenal cortex. Xastor oil and benzyl benzoate in a 4:1 ratio caused intracellular as well as intercellular changes. In the zona fasciculata there were alterations in mitochondrial shape, size, and matrix. Intercellular changes affected the morphology of macrophages in the zona fasciculata and zona reticularis. It is believed that the castor oil and benzyl benzoate vehicle caused stress-induced changes.

Rouleau formation and fertility of spermatozoa in guinea pigs treated with cyproterone acetate

The effects of cyproterone acetate (CA) on fertility of spermatozoa and rouleau formation were investigated in male guinea pigs. Twelve of 15 matings during CA treatment resulted in pregnancy even when rouleaux were absent in ejaculates, indicating that the rouleau condition is not necessary for the fertilizing ability of guinea pig spermatozoa. Examination of epididymides and vasa deferentia revealed that rouleaux diminished progressively with treatment time and were absent in the excurrent ducts of all males during the eighth and ninth weeks of treatment. Following a latent period after treatment, rouleaux were first noted in a specific epididymal region and were present throughout the distal excurrent ducts and ejaculates by 6 wk posttreatment. This sequence of rouleau loss and reappearance in the excurrent ducts suggests that rouleau formation is dependent on a regional epididymal influence that requires androgens. Spermatogenesis was not arrested; however, seminal vesicle and body weights were reduced in treated males.

Cyproterone acetate: I. Microquantity releasing device of cyproterone acetate and its failure in inducing functional sterility in male rats

Prasad and his coworkers emphasized that microquantities of cyproterone acetate (CPA) when continuously available developed functional sterility in male rats by interfering the epididymal physiology. In our experimental rats either 2 or 3 capsules containing CPA as per the specification of Prasad were implanted subcutaneously and left for 300 and 250 days, respectively. Fertility test was made every month and it was observed that all the experimental animals were able to impregnate female rats throughout the experiment. Excepting the epididymis the weight of testes and other accessory glands did not differ from the controls in the animals which had 2 CPA capsules for 300 days; On the other hand, the animals which received 3 CPA capsules for 250 days showed significant reduction in weight of all the acessory glands including the testes.

Fine structure of the testis and epididymis of rats treated with cyproterone acetate

Adult male rats were administered the antiandrogen, cyproterone acetate, for 4, 8 or 12 weeks, and the histology and fine structure of the testis and several parts of the epididymis were studied. After treatment for 8 or 12 weeks, the testes of treated animals displayed a great reduction in the abundance of late spermatids. Necrotic cells, many of which were identified as cap-phase spermatids, were present in the seminiferous epithelium. Sertoli cells contained many large lipid droplets and lysosome-like structures with a content of cellular debris, including parts of spermatids. Leydig cells of treated rats were smaller than those of control animals at all the intervals studied. Sperm were absent from the lumen of the middle segment, or caput epididymidis, of severely affected specimens. In the terminal segment, or cauda epididymidis, the microscopic appearance varied in different regions. In the proximal part of the cauda epididymidis, the lumen was usually clear of sperm. The epithelium was tall and the light cells were very large and distended with many dense bodies resembling lysosomes. In contrast, in the distal part of the cauda epididymidis, the lumen was filled with sperm and debris, which appeared to be derived from germ cells. It is suggested that the light cells of the epididymal epithelium may have a role in clearing the lumen in the proximal part of the cauda epididymidis, in which they are particularly large and numerous. The results suggest that in the presence of cyproterone acetate, germ cells develop up to a cap-phase spermatids and then begin to undergo degeneration and death. This alteration may have an important role in the antifertility effect of the drug, but changes in the epididymis may contribute also.

Alterations in the fine structure of the prostate and seminal vesicle of rats treated with cyproterone acetate

Young adult male rats were treated with daily injections of 10 mg of cyproterone acetate for periods up to 16 weeks. Samples of the ventral prostate and the seminal vesicle were studied with the light and electron microscopes. Alterations visible with the light microscope included decreases in cell size, cytoplasmic basophilia, the size of the nucleolus, and the amount of luminal secretory material. Ultrastructural changes in the epithelium of both glands involved mainly the organelles that participate in the formation of secretions. Large declines were observed in the abundance of rough endoplasmic reticulum, size of the Golgi apparatus, and number of secretory vacuoles. Lipid droplets accumulated in the seminal vesicle epithelium, and lysosomes were numerous in both glands. Changes were first observed microscopically in the seminal vesicle after one week and in the prostate after two or three weeks. Maximal development of the alteration occurred after treatment for approximately eight weeks.

Studies on the physiology and biochemistry of mammalian epididymis: effect of flutamide, a nonsteroidal antiandrogen, on the epididymis of the rat

The effect of flutamide (Sch 13521; 4'-nitro-3'-trifluoromethylisobutyranilide), a nonsteroidal antiandrogen, on male rat genital organs was studied. Administered at a dose of 25 mg/kg body weight daily for 30 days, flutamide caused a significant increase in the weight of the testis but had no effect on spermatogenesis and Leydig cell morphology. The secretory activity of the epididymis, as evidenced by the level of glycerylphosphoryl-choline and sialic acid, either remained unaffected or was stimulated. There was a significant decrease in seminal vesicle and ventral prostate weight and in the fructose content of the coagulating gland. The anti-androgen at the dose used did not affect the fertility of the rats. The significance of these findings is viewed in relation to the hypothesis of a differential threshold requirement of androgen for the epididymis and the accessory sex glands. The potentiality of antiandrogens as extragonadal antifertility agents in the male is discussed.

Comparative effects of castration and antiandrogen treatment on the aortas of hypertensive and normotensive male rats

Lowering androgen levels by gonadectomy or inhibiting circulating androgen by administration of the antiandrogen, BOMT, did not affect morphological or compositional changes induced by hypertension in the thoracic aorta of male rats. However, treatment with cyproterone acetate, another antiandrogenic drug, did result in the maintenance of total elastin and collagen at levels the same as those for the normotensive group and significantly lower than those for other treated and untreated hypertensive groups. In rapidly growing normotensive rats, neither castration nor administration of an antiandrogenic drug had any detectable effect on aortic wall morphology or composition regardless of whether the latter was expressed in absolute or relative terms. These findings suggest that growth and hypertension result in the accumulation of connective tissue proteins, elastin, and collagen in the blood vessel wall by different, independent mechanisms.