title: Effects of recombinant bovine somatotrophin, insulin-like growth factor-I and insulin on the proliferation of bovine granulosa cells in vitro.
abstract: Treatment of heifers with recombinant bovine somatotrophin (BST) significantly increases the population of small ovarian follicles and peripheral concentrations of somatotrophin, insulin-like growth factor-I (IGF-I) and insulin. To investigate the possible mechanism(s) involved in the action of BST on ovarian follicles, the effects of BST, IGF-I and insulin, given alone or in combination with either FSH or LH, on the proliferation of bovine granulosa cells in vitro were examined using a serum-free culture system. Bovine granulosa cells were obtained from antral follicles classified into three size categories according to diameter: small < 5 mm; medium-sized 5-10 mm and large > 10 mm. The proliferation of granulosa cells was assessed by the incorporation of [3H]thymidine into the cultured cells. Both FSH and LH (1-1000 ng/ml) inhibited the proliferation of bovine granulosa cells obtained from all three size classes of follicles in a dose-dependent manner. BST, at doses ranging from 1 to 1000 ng/ml, had no effect on the proliferation of granulosa cells from small and medium-sized follicles, but inhibited the division of granulosa cells from large follicles in a dose-dependent manner. Treatment with either IGF-I (10-3000 ng/ml) or insulin (0.5-1000 ng/ml) stimulated, in a dose-dependent manner, the proliferation of granulosa cells obtained from all three size categories of follicles. No synergistic interaction between BST (30 ng/ml) and either FSH (50 ng/ml) or LH (5 ng/ml) was observed in granulosa cells from all three size classes of follicles.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: AFRC Roslin Institute (Edinburgh), Midlothian, U.K.
authors.forename: J G
authors.initials: JG
authors.lastname: Gong
authors.forename: D
authors.initials: D
authors.lastname: McBride
authors.forename: T A
authors.initials: TA
authors.lastname: Bramley
authors.forename: R
authors.initials: R
authors.lastname: Webb
mesh_terms: D000818:Animals; D002417:Cattle; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D006107:Granulosa Cells / Q000166:cytology / Q000187:drug effects*; D013006:Growth Hormone / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D007986:Luteinizing Hormone / Q000494:pharmacology; D006080:Ovarian Follicle / Q000033:anatomy & histology; D011994:Recombinant Proteins / Q000494:pharmacology
chemical_list: D007328:Insulin; D011994:Recombinant Proteins; D007334:Insulin-Like Growth Factor I; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D013006:Growth Hormone