Abstract
The concentration of testosterone has been measured in spermatic venous blood from eutopic and cryptorchid testes in the same anesthetized dog in experiments lasting for 90 minutes. Both testes secreted testosterone and increased production of the hormone following intravenous administration of gonadotrophin. The production of testosterone by the cryptorchid testis was, however, lower than that by the eutopic organ thus demonstrating that the condition of cryptorchism is associated with decreased secretion rates of testosterone in the canine.