Factors influencing the functional development of the male gonad

Abstract

All exps. were performed on immature male white rats belonging to the Wistar stock. Implantations or injections were started when the animals were 3 to 4 weeks old and continued for several weeks. Litter mates were invariably used as controls. The implantation of bovine anterior pituitary lobe substance caused (1) inhibition of growth of the testes; (2) inhibition of spermatogenic development; (3) some inhibition of the growth of the secondary sex organs; (4) hypertrophy of the suprarenal glands; (5) no effect on body weight. The injection of a highly purified extract prepared from urine of pregnant women and containing gonadotropic hormones caused (1) increase in the weight of the testes; (2) no effect on spermatogenesis. The implantation of adrenaline-free suprarenal cortical tissue or injection of suprarenal extracts (lipid extract; Swingle and Pfiffner extract) caused (1) inhibition of growth of the testes; (2) a variable and usually small effect on the body-weight, insufficient to account for the effects on the testes. The implantation of rabbit''s heart muscle brought about (1) some inhibition of growth of the testes; (2) inhibition of the growth of the secondary sex organs; (3) no effect on spermatogenesis. These effects have been carefully compared with those resulting from the implantation of bovine anterior lobe. The results are discussed in relation to the mechanism controlling development and function of the testes and to the problem of hormone antagonism.