HORMONAL MILIEU OF SEMINIFEROUS TUBULES IN NORMAL AND CRYPTORCHID RAT

The intratesticular concentration of androgens seems to be of more importance for normal spermatogenesis than the concentration of androgens in the peripheral blood. Therefore, the levels of testosterone, 5α ‐ dihydrotestosterone (DHT), androstenedione and FSH in the interstitial fluid of the rat testis were determined by radioimmunoassay. The following concentrations were obtained from the interstitial fluid of normal rats and from rats cryptorchid between 60 and 90 days of age: Testosterone 137 ± 25 (mean ± SEM) and 271 ± 34 ng/ml, DHT 11 ± 2 and 22 ± 5 ng/ml, androstenedione 8 ± 2 and 20 ± 4 ng/ml, respectively. The sum of testosterone and DHT in serum did not differ in the two groups. Serum FSH concentrations were significantly increased in the cryptorchid rats (942 ± 73 ng/ml) as compared to the control rats (600 ± 38 ng/ml). These elevated levels were also found in the testicular interstitial fluid (425 ± 33 ng/ml in controls, 641 ± 43 ng/ml in cryptorchid rats). It is thus evident that in the cryptorchid rat, both FSH and androgens are available to the seminiferouse tubules in significantly elevated amounts. Since these are the only hormones which are known to be of importance in spermatogenesis, the impaired Sertoli cell function and depletion of germinal cells in cryptorchidism is not due to an absolute shortage of stimulatory hormones. Copyright © 1978, Wiley Blackwell. All rights reserved