Regional differences in androgen thresholds of the epididymis of the castrated rat

A Common Endocrine Signature Marks the Convergent Evolution of an Elaborate Dance Display in Frogs

AbstractUnrelated species often evolve similar phenotypic solutions to the same environmental problem, a phenomenon known as convergent evolution. But how do these common traits arise? We address this question from a physiological perspective by assessing how convergence of an elaborate gestural display in frogs (foot-flagging) is linked to changes in the androgenic hormone systems that underlie it. We show that the emergence of this rare display in unrelated anuran taxa is marked by a robust increase in the expression of androgen receptor (AR) messenger RNA in the musculature that actuates leg and foot movements, but we find no evidence of changes in the abundance of AR expression in these frogs' central nervous systems. Meanwhile, the magnitude of the evolutionary change in muscular AR and its association with the origin of foot-flagging differ among clades, suggesting that these variables evolve together in a mosaic fashion. Finally, while gestural displays do differ between species, variation in the complexity of a foot-flagging routine does not predict differences in muscular AR. Altogether, these findings suggest that androgen-muscle interactions provide a conduit for convergence in sexual display behavior, potentially providing a path of least resistance for the evolution of motor performance.

Immunolocalization of androgen and vitamin D receptors in the epididymis of mature ram (Ovis aries)

This study illustrated the immunohistochemical distribution of androgen and vitamin D receptors of epididymis in 20 sexually mature ram (Rahmani breed) with average age ranged from (2^_4) years and average weight ranged from (50^_65kg). Androgen receptor was localized in the cytoplasm of both ciliated and non ciliated cells of efferent ductules, besides the principal cells via the entire epididymal duct. The principal cells of both corpus and proximal cauda epididymis showed the highest immunoreactivity to androgen receptors. Furthermore, vitamin D receptor was localized in the cytoplasm of all epithelium of the efferent ductules besides principal cells of all epididymal regions, however the immunoreaction was significantly higher in the efferent ductules, distal caput and distal cauda epididymis. In conclusion, these results suggest that the function of ram epididymis is regulated by both androgen and Vitamin D.

Differential distribution of dihydrotestosterone and estradiol binding sites in the epididymis of the mouse. An autoradiographic study

The distribution of androgen and estrogen binding sites in the mouse epididymis was assessed by autoradiography with 3H dihydrotestosterone (3H DHT) and 3H estradiol (3H E2). Nuclear labeling with 3H DHT in principal cells of the epithelium is high in the caput, low in the corpus, and high again in the cauda. 3H E2 also binds to the nuclei of principal cells. The pattern is distinct from 3H DHT: nuclear labeling is highest in the ductulus efferens and high in the caput, but low or absent in corpus and cauda. Apical cells in caput and clear cells in corpus and cauda are moderately labeled with 3H DHT but heavily labeled with 3H E2. Connective tissue cells show variable labeling with both hormones, being more pronounced with 3H E2. Smooth muscle cells are also labeled to varying degrees with both hormones. The different binding patterns of 3H DHT and 3H E2 and the results of the competition studies with unlabeled compounds demonstrate that in the epididymis besides the specific nuclear receptors for androgen also estrogen receptors are present.

Studies of the guinea pig epididymis. I. Ultrastructure and quantitative morphology of the principal cells

The guinea pig epididymis is subdivided into seven zones. The ultrastructure and morphology of the principal cells in these zones is analyzed. The position, shape and content of the nuclei are variable along the length of the epididymal duct. Features characteristic of absorptive activity, such as micropinocytotic caveolae, vacuoles, and multivesicular bodies are of high concentration in zone IV and VI. The Golgi apparatus, rough endoplasmic reticulum and secretion granules are organelles and inclusions implicated to secretory functions and in this study are not found in the following concurring amounts within the principal cells of the seven zones: the Golgi apparatus exhibits a trend of increase from zone II to zone VII while the rough endoplasmic reticulum decreases. Secretion granules, though, are detected only in zones II and III, not only in the supra-, but also in the peri- and infranuclear regions. This possibly implies an exocrine secretory function. Lamellar whorls and profiles of tubular smooth endoplasmic reticulum are concentrated in the supranuclear and adluminal regions of zones I, II and VI. A high concentration of large lipid droplets is a consistent feature of the perinuclear region of zone II. Mitochondria and lysosomes are detected in relatively large amounts along the epididymal duct. The correlations of these morphological characteristics with respect to their possible functional role are discussed.

Testosterone concentration within the tunica vaginalis of boys and adult men

The testosterone level in fluid contained in the tunica vaginalis has been determined in 25 adult men referred for infertility and in 20 boys aged 0-10.5 years operated on for hydrocele. The median concentrations of testosterone were found to be 392 nmole/1 (range 78-957) and 1.1 nmole/1 (range 0.16-182), respectively. The median value for adult men was 20 times the concentration of testosterone found in the peripheral blood of that group while the median value for the boys was 4 times that found in their peripheral blood. It is concluded, firstly, that the high level of testosterone in the peritesticular space of adult men strongly indicates that diffusion of testosterone through the testicular capsule does take place. Secondly, testosterone levels in fluid from the peritesticular space which significantly exceeds those in peripheral blood in prepubertal boys furnishes evidence of testicular secretion of testosterone in that age group. Consequently, the peritesticular tissues such as the epididymis, gubernaculum and scrotum are exposed to quantities of testosterone far exceeding those brought by the general circulation.

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.

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.