Androgens and related compounds in the spermatic vein blood of domestic animals. IV. Testicular androgens in the ram, boar and stallion.

Abstract

SUMMARY Testosterone and androstenedione were identified in the spermatic vein blood of the ram, the boar and the stallion. Neither of the two steroids could be detected in the arterial or peripheral venous blood, indicating that testosterone and androstenedione are secretory products of the testis in the three species studied. Small amounts of testosterone (14–20 μg./hr.) were secreted by the testes of the young ram and boar already at the age of 3½ months. The testes of the mature boar are capable of releasing testosterone into the blood stream at the rate of 184–716 μg./hr. On the basis of these findings it is suggested that testosterone constitutes the principal testicular androgen in the boar. This conclusion differs from the view expressed by earlier investigators with respect to the boar, but is consistent with the results obtained in all other mammalian species thus far examined. Intravenous administration of human chorionic gonadotrophin (2–15 i.u./kg.) was followed by a prompt increase in the rate of testicular secretion of androgen in most of the experimental animals; however, this observation requires confirmation, in view of the limited number of experiments carried out.