Leydig Cell Differentation, Steroid Metabolism by the Interstitium in Vitro and the Growth of the Accessory Sex Organs in the Rat

Steroid Metabolism by the Seminiferous Tubules in Vitro and Spermatogenesis in the Developing Rat

“…The formation of large amounts of 5a-pregnane compounds is evidence for the presence of high levels of 5a-reductase in the seminiferous tubules acting primarily on progesterone. This contrasts with the situation previously described for the interstitium where androsterone was the principal product of ring A reduction (Tsang et al, 1973). This suggests a high measure of substrate specificity for 5a-reductase in the two tissues and accounts for the formation of relatively large amounts of both 5a-androstane and 5a-pregnane compounds in incubations with cell fractions obtained from entire testes (see Inano, Hori & Tamaoki, 1967 (Tsang et al, 1973).…”

“…This contrasts with the situation previously described for the interstitium where androsterone was the principal product of ring A reduction (Tsang et al, 1973). This suggests a high measure of substrate specificity for 5a-reductase in the two tissues and accounts for the formation of relatively large amounts of both 5a-androstane and 5a-pregnane compounds in incubations with cell fractions obtained from entire testes (see Inano, Hori & Tamaoki, 1967 (Tsang et al, 1973). This suggests that androgens produced by the interstitium may play some rôle in spermiogenesis and the subsequent maintenance of spermatogenesis in adult animals.…”

“…Studies on steroid metabolism in vitro by isolated seminiferous tubules of rats denuded of their germ cells by heat\x=req-\ treatment has led to the view that not only Leydig cells but also Sertoli cells may be a major source of androgens Lacy et al, 1969). Similar conclusions have also been reached by Ellis & van Kampen (1971) (Tsang, Lacy & Collins, 1973). In the present work, the relationship between spermatogenesis and steroid metabolism in vitro by isolated tubules has been studied in the rat from pre-puberty to maturity.…”

“…Tubules were obtained by dissection from the same testes as those which provided the tissue for previous studies on the interstitium (Tsang et al, 1973 (Text-fig. 1).…”

PRODUCTION OF TESTOSTERONE, 5α-Androstane-3α,17β-Diol AND ANDROSTERONE BY DISPERSED TESTICULAR INTERSTITIAL CELLS AND WHOLE TESTES IN VITRO

“…It is uncertain which of these pathways predominates and there is some uncertainty as to the cellular origin of androstanediol. Based on the metabolism of radioactively labelled substrates, the interstitial tissue appears to be the major site of formation of androstanediol (Folman, Ahmad, Sowell «fe Eik-Nes, 1973;Tsang, Lacy & Collins, 1973). Consistent with this view is the observation that the administration of luteinizing hormone (LH) to immature rats results in rapid increases in the serum concentrations of androstanediol and androsterone (Moger, 1977a).…”