IGF-II in follicular wall and their binding proteins in follicular fluid of cows with induced cystic ovarian disease

REY, F.; PALOMAR, M.M.; SALVETTI, N.R.; DALLARD, B.E.; BARBEITO C.G.; ORTEGA, H.H

Chillan, Chile

Congreso; Reunión Anual de la Sociedad Chilena de Reproducción y Desarrollo; 2007

There is increasing evidence for an important regulatory role for the insulin-like growth factor (IGF) system in proliferation and differentiation of granulosa and theca cells, however the detailed pattern of IGF-II expression in bovine cystic ovarian disease (COD) remains controversial. Therefore, the objectives of this study were to determine changes in IGF-II in the follicular wall and their Binding Proteins (IGFBPs) in follicular fluid of cows with ACTH-induced follicular cysts, and to compare them with normal cycling (control) cows. By immunohistochemistry and digital image analysis, an intense positive immunostaining with anti-IGF-II was observed in granulosa and in low amounts in theca cells of cystic follicles. In tertiary follicles the staining was less intense (p < 0.05). IGFBPs in follicular fluid were analyzed by Western ligand blotting and concentrations of IGFBPs were higher (P < 0.05) in control than in cystic ovaries. The results suggest that the increased presence of IGF-II in follicular wall, along with the decrease in IGFBPs concentrations in follicular fluid, could alter the bioavailability of intrafollicular IGFs in cystic follicles. These data support the hypothesis that IGF-II system may participate in the pathogenesis of COD in cattle.