Follicle-stimulating hormone increases guanine nucleotide-binding regulatory protein subunit alpha i-3 mRNA but decreases alpha i-1 and alpha i-2 mRNA in Sertoli cells.
FSH interacts with a guanine nucleotide-binding protein (G-protein)-coupled receptor, which in turn modulates signal transduction via the G-protein subunit alpha s. However, it is unknown whether FSH regulates alpha-subunit gene expression and whether G-protein alpha-subunit genes other than alpha s are modulated in FSH-stimulated signal transduction. Regulation of mRNA for alpha s and alpha i-2 was studied in primary cultures of rat Sertoli cells because these proteins are linked to the control of adenylyl cyclase. In addition, mRNA for alpha i-1 and alpha i-3 were quantified because these proteins are putatively linked to ion channels but have not been well characterized in the Sertoli cell. Northern blot analyses demonstrated that FSH induced a dose-dependent increase in steady state levels of alpha i-3 mRNA. In contrast, FSH caused a dose-dependent decrease in levels of alpha i-1 and alpha i-2 mRNA. No significant effect of FSH on alpha s mRNA levels was detectable. The time course of FSH effects showed a 75% decrease in alpha i-1 mRNA levels, a 50% decrease in alpha i-2 mRNA levels and a nearly 3-fold increase in levels of alpha i-3 mRNA between 4-6 h of treatment with 100 ng/ml FSH. Steady state levels of alpha i-1 and alpha i-2 mRNA returned to pretreatment levels after 10 h FSH treatment, while alpha i-3 mRNA returned to a new steady state level approximately 50% greater than the pretreatment level.(ABSTRACT TRUNCATED AT 250 WORDS)
Loganzo
F
F
Department of Biochemistry and Molecular Biology Albany Medical College, New York 12208.
Fletcher
P W
PW
D000818:Animals; D015152:Blotting, Northern; D000242:Cyclic AMP / Q000502:physiology; D005640:Follicle Stimulating Hormone / Q000502:physiology*; D019204:GTP-Binding Proteins / Q000235:genetics*; D005786:Gene Expression Regulation / Q000502:physiology; D008297:Male; D010446:Peptide Fragments / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000378:metabolism*; D011863:Radioimmunoassay; D051381:Rats; D017208:Rats, Wistar; D012708:Sertoli Cells / Q000378:metabolism*
D010446:Peptide Fragments; D012333:RNA, Messenger; D005640:Follicle Stimulating Hormone; D000242:Cyclic AMP; D019204:GTP-Binding Proteins