Effects of FSH and IGF-I on immature rat Sertoli cells: inhibin alpha- and beta-subunit mRNA levels and inhibin secretion.
Effects of follicle-stimulating hormone (FSH) and insulin-like growth factor-I (IGF-I) on inhibin production by cultured Sertoli cells from 21- to 23-day-old rats were studied. The expression of inhibin alpha- and beta-subunit mRNAs, and inhibin immunoreactivity and in vitro bioactivity were estimated. Using a cDNA probe corresponding to the alpha-subunit of bovine inhibin, specific hybridization with a 1.5-1.7 kilobase (kb)mRNA species was observed. Addition of FSH to the cultured Sertoli cells for 24 h markedly increased the level of this mRNA in a dose-dependent way. IGF-I had no effect on the intensity of the hybridization. Using a cDNA probe corresponding to the beta B-subunit of human inhibin, 3.5 and 4.2 kb mRNA species were detected. FSH and IGF-I had no effect on the hybridization signal. No hybridization was observed with a cDNA probe corresponding to the beta A bovine inhibin subunit. Inhibin activity was detected in cells and medium by immunoassay, and in the medium by in vitro bioassay. FSH stimulated both immunoreactivity and in vitro bioactivity, whereas IGF-I had no effect at all. The present effect of FSH on inhibin alpha-subunit mRNA expression in cultured Sertoli cells indicates that regulation of inhibin production by FSH includes an effect at the transcriptional level. However, this does not exclude additional translational and posttranslational effects.
D000818:Animals; D005640:Follicle Stimulating Hormone / Q000494:pharmacology*; D066298:In Vitro Techniques; D007265:Inhibins / Q000235:genetics* / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D046911:Macromolecular Substances; D008297:Male; D012333:RNA, Messenger / Q000187:drug effects / Q000235:genetics*; D051381:Rats; D011919:Rats, Inbred Strains; D012708:Sertoli Cells / Q000187:drug effects / Q000378:metabolism*; D012741:Sexual Maturation; D013002:Somatomedins / Q000494:pharmacology*
D046911:Macromolecular Substances; D012333:RNA, Messenger; D013002:Somatomedins; D007265:Inhibins; D007334:Insulin-Like Growth Factor I; D005640:Follicle Stimulating Hormone