Testosterone Concentration in Spermatic Vein Plasma of the Developing Ram

A study of the growth, histological development, and androgen secretion of the ram testis was made in animals from ages 47 days through adulthood. An estimate of the spermatogenic activity of seminiferous tubules, determined histologically, served as an index of maturity. By 90 days of age spermatogenic activity of the testis was usually underway and, judging by the presence of spermatozoa, fertility could be attained by 120–150 days of age. Analyses of testicular androgen secretion by gas–liquid chromatography revealed that testosterone is the dominant unconjugated testicular steroid in the circulation during sexual maturation of the ram lamb. The greater secretion of testosterone in the case of the mature ram was reflected in the significant correlation observed to hold between the testosterone secretion rate and the age of the ram.