Differential regulation by FSH and IGF-I of extracellular matrix IGFBP-5 in bovine granulosa cells: effect of association with the oocyte.
Inhibition of insulin-like growth factor (IGF)-I induced DNA synthesis in bovine oocyte-cumulus complexes (OCCs) caused by follicle-stimulating hormone (FSH) has been linked to changes in the extracellular matrix which do not occur in mural granulosa cells (MGCs). We investigated regulation by IGF-I and FSH of secreted and extracellular matrix entrapped IGF-binding proteins. OCCs and MGCs from bovine ovaries were cultured in media supplemented with IGF-I and FSH for 24 h. Culture media and extracellular matrix were analysed for IGF-binding proteins by Western ligand blot and immunoblot and found to contain principally IGFBP-3 and -5. The combined treatment of IGF-I and FSH increased the concentration of IGFBP-3 in OCC and MGC conditioned media by 4- and 6-fold, respectively. Treatment of OCCs and not MGCs with IGF-I and FSH together increased extracellular matrix IGFBP-5 by 2.5-fold. The differential regulation of extracellular matrix IGFBP-5 in OCCs compared to MGCs suggest involvement of changes in the extracellular matrix brought about by IGF-I and FSH in overall regulation of IGF-I in the ovarian follicle.
Ingman
W V
WV
Department of Obstetrics and Gynaecology, Medical School, University of Adelaide, SA, Australia. wingman@medicine.adelaide.edu.au
Owens
P C
PC
Armstrong
D T
DT
D000818:Animals; D002417:Cattle; D002450:Cell Communication / Q000502:physiology*; D016326:Extracellular Matrix Proteins / Q000502:physiology; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology / Q000502:physiology*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D006107:Granulosa Cells / Q000166:cytology / Q000502:physiology*; D018975:Insulin-Like Growth Factor Binding Protein 5 / Q000502:physiology*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology / Q000502:physiology*; D009865:Oocytes / Q000166:cytology / Q000502:physiology
D016326:Extracellular Matrix Proteins; D018975:Insulin-Like Growth Factor Binding Protein 5; D007334:Insulin-Like Growth Factor I; D005640:Follicle Stimulating Hormone