Concentrations of oestradiol and testosterone in peripheral and spermatic venous blood of dogs with unilateral cryptorchidism.

Plasma testosterone and oestradiol concentrations were measured in peripheral and spermatic venous blood of 13 dogs with unilateral inguinal cryptorchidism, 9 dogs with unilateral abdominal cryptorchidism, and in a control group of 36 mature normal dogs. The hormone concentrations were similar in the three groups, both in the peripheral and in the spermatic venous blood. The weight of the testes in the control group was correlated with the body weight and there was no significant difference between the weight of the right and the left testes. The weight of the abdominal testes was lower than that of the inguinal testes, and there was no compensatory enlargement of the contralateral scrotal testis. The cryptorchid testes showed little or no histological evidence of spermatogenesis, and spermatogenesis was usually normal in the scrotal testes.