First spermiation and spermatozoa concentration in hemicastrated rats

Male rats ten days of age were divided in three groups: a) hemicastrated, b) sham operated and c) control. They were daily sacrificed between 30 and 50 days of age. Wet weight and dry weight were determined in testis, seminal vesicles and epididymis. The concentration of spermatozoa was measured in testis and caput epididymis. The results show a significant increase in both wet and dry weight of testis of hemicastrated animals (40.5% at 30 days of age). The total population of psermatozoa per testis is higher in hemicastrated after 48 days of age. The first arrival of spermatozoa to the caput epididymis (first spermiation) which occurs in control at 45 days of age is delayed 48 hours in the hemicastrated group, however at 50 days of age the concentration of spermatozoa in the caput is higher than in control. We related our results to the rise in plasma FSH which occurs immediately after hemicastration and involved a larger and higher exposure of the testis to FSH.