Abstract
A total of 29 adult unilaterally cryptorchid dogs were examined for their spermatogenic function and plasma androgen levels. The testes, epididymides, and prostates were studied histologically. The 4-androstenedione (A), 5α-dihydrotestosterone (DHT), and testosterone (T) levels in the peripheral and spermatic venous plasma were measured by the RIA method to estimate their endocrine functions. The mean diameter of seminiferous tubules in the undescended testis was 125μm about half that in the normal testis. A few primary spermatocytes were found in the testis of about one-theird of the cryptorchid dogs. Neither spermatids nor spermatozoa were seen in any undescended testis and Leydig cells were tended to be atrophic. Primary spermatocytes and spermatids were significantly fewer in the contralateral than in the normal testis (P<0.01). The development of epididymides and prostates was demonstrated in the cryptorchid dogs. Mean spermatic venous plasma A and DHT levels were significantly higher in the cryptorchid than in normal dogs (P<0.01), in contrast to the significantly lower mean spermatic venous plasma T level (P<0.01). The peripheral venous plasma A and T levels showed the same changes as did the spermatic venous plasma androgen levels, but the DHT level was nearly equal to that in normal dogs. The spermatogenesis and T secretory function of the scrotal as well as uncescended testis in the unilateral cryptorchid dog were inferior to those in normal dogs.
