title: Insulin-like growth factor binding protein-3 inhibits porcine granulosa cell function in vitro.
abstract: Recombinant human insulin-like growth factor binding protein-3 (rhIGFBP-3) effects on basal, insulin-like growth factor I (IGF-I)-, and follicle-stimulating hormone (FSH)-stimulated progesterone (P4) secretion and [3H]aminoisobutyric acid (AIB) uptake by primary porcine granulosa cells (MDGs) and MDGs that have been passaged once (MDGp1) were assessed. Cells were treated concurrently or were preincubated with rhIGFBP-3 followed by treatment. rhIGFBP-3 had no effect on MDG or MDGp1 cell numbers after 24 h. Cotreatment with rhIGFBP-3 inhibited P4 secretion after treatment with FSH, IGF-I, and FSH plus IGF-I. FSH did not stimulate [3H]AIB uptake. However, the IGF-I-stimulated increase in [3H]AIB uptake was completely prevented by concurrent treatment with IGFBP-3. Preincubation of MDGp1 cells with IGFBP-3 dose dependently inhibited FSH- and IGF-I-stimulated P4 secretion. This inhibition was associated with increased cell association of the binding protein and increased IGF-I binding to the cells. These results indicate that IGFBP-3 is inhibitory to a variety of crucial functions in porcine granulosa cells, supporting a role for it in the regulation of granulosa cell function.
authors.affiliation: Department of Medicine, Milton S. Hershey Medical Center, Pennsylvania State University, Hershey 17033, USA.
authors.forename: S E
authors.initials: SE
authors.lastname: Samaras
authors.forename: J M
authors.initials: JM
authors.lastname: Hammond
mesh_terms: D000621:Aminoisobutyric Acids / Q000378:metabolism; D000818:Animals; D001667:Binding, Competitive; D001692:Biological Transport / Q000187:drug effects; D002352:Carrier Proteins / Q000494:pharmacology*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D006107:Granulosa Cells / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I / Q000378:metabolism / Q000494:pharmacology; D007700:Kinetics; D011374:Progesterone / Q000096:biosynthesis* / Q000378:metabolism; D017526:Receptor, IGF Type 1 / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology; D013552:Swine
chemical_list: D000621:Aminoisobutyric Acids; D002352:Carrier Proteins; D018969:Insulin-Like Growth Factor Binding Proteins; D011994:Recombinant Proteins; D011374:Progesterone; D007334:Insulin-Like Growth Factor I; D005640:Follicle Stimulating Hormone; D017526:Receptor, IGF Type 1