Kinetic study of HCG induced decrease of microsomal 7α-hydroxylase activity in rat testes

Current aspects of Leydig cell function and its regulation

“…In addition to these steroidogenic lesions, chronic hCG and LHRH treatment seems to cause, in the mature rat, a qualitative shift from the normal dominating 7a-hydroxylation pathways to 5a-reduction pathways (Eechaute et al, 1980;Carmichael et al, 1980;Lacroix et al, 1977Lacroix et al, , 1984. There is therefore a shift from a adult type of steroidogenic pattern to one similar to that observed in immature testes (Ficher & Steinberger, 1971;Rosness et al, 1977;Terada et al, 1980;Tsuji et al, 1984).…”

“…The interstitial cells of fetal, neonatal, prepubertal and seasonally quiescent animals respond to desensitizing doses of hCG with an increase in testosterone synthesis and LH receptor numbers Huhtaniemi, Katikineni & Catt, 1981b;Huhtaniemi, Nozu, Warren, Dufau & Catt, 1982;Huhtaniemi et ai, 1984b;Amador, Bartke, Klemcke, Siler-Khodr & Stallings, 1985;Amsterdam, Venter & Huhtaniemi, 1985). It seems that the doseas well as the age-dependent differences in the steroidogenic response of Leydig cells are not merely quantitative in nature (Ficher & Steinberger, 1971;Lacroix, Eechaute & Leusen, 1977;Eechaute, Lacroix & Leusen, 1980). I t r acellu I a r events: regulation of steroidogenic elements The Leydig cell is a highly differentiated cell specialized in the synthesis and secretion of androgens.…”