Ovarian action of leptin: effects on insulin-like growth factor-I-stimulated function of granulosa and thecal cells.
To test the hypothesis that leptin signals metabolic information to the reproductive system in cattle by directly affecting IGF-I-induced ovarian cell function, granulosa and thecal cells from bovine ovarian follicles were cultured for 2 d in serum-free medium with added hormones. Recombinant human leptin at 30 and 300 ng/mL had no effect on basal thecal cell steroidogenesis or thecal cell numbers. However, 300 but not 30 ng/mL of leptin attenuated (p < 0.05) luteinizing hormone-induced androstenedione production by 24% in the absence of IGF-I and by 16% in the presence of IGF-I. Leptin had no effect on IGF-I-induced estradiol production in the presence of follicle-stimulating hormone (FSH), but at 100 ng/mL, leptin inhibited (p < 0.05) FSH plus IGF-I-induced progesterone production and granulosa cell proliferation by 29 and 31%, respectively. Leptin did not compete for 125I-IGF-I binding to granulosa or thecal cells, whereas unlabeled IGF-I did. In conclusion, leptin has weak inhibitory effects on gonadotropin- and/or IGF-I-induced steroidogenesis of thecal and granulosa cells.
Spicer
L J
LJ
Department of Animal Science, Oklahoma State University, Stillwater 74078, USA. igf1Leo@okstate.edu
Chamberlain
C S
CS
Francisco
C C
CC
D000735:Androstenedione / Q000096:biosynthesis; D000818:Animals; D001667:Binding, Competitive; D002417:Cattle; D002452:Cell Count; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004958:Estradiol / Q000096:biosynthesis; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D006107:Granulosa Cells / Q000187:drug effects* / Q000378:metabolism*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism / Q000494:pharmacology; D020738:Leptin / Q000378:metabolism / Q000494:pharmacology*; D007986:Luteinizing Hormone / Q000494:pharmacology; D011374:Progesterone / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000494:pharmacology; D013799:Theca Cells / Q000187:drug effects* / Q000378:metabolism*
D020738:Leptin; D011994:Recombinant Proteins; D000735:Androstenedione; D011374:Progesterone; D004958:Estradiol; D007334:Insulin-Like Growth Factor I; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone