Development of the os penis in genital tubercles cultured beneath the renal capsule of adult rats.

Genital tubercles of male and female rats were cultured beneath the renal capsule of castrated and intact adult male rats treated with androgens, oestrogen, or anti-androgen, and the development of the os penis in the transplants was studied. When the genital tubercles were cultured in normal male hosts, a membrane bone and a hyaline cartilage of the proximal segment of the os penis were formed 8-11 days after transplantation, and a fibrocartilage of the distal segment of the os penis at 11-14 days. In genital tubercles cultured in castrated males, the rudiments of both the proximal and distal segments remained as undifferentiated mesenchymal cell masses. However, similarly cultured genital tubercles were found to develop cartilages and bone when the hosts were treated with high doses of androgens. The potency of androgen-dependent chondrogenesis and osteogenesis was equivalent in the male and female genital tubercles. Chondrogenesis and osteogenesis of the os penis were caused by androgens, while the rudiments of the os penis were formed independently of androgens. The overt differentiation of the corpus cavernosum penis was also caused by androgens.