Role of Components of the Insulin-like Growth Factor System in the Early Stages of Ovarian Follicular Persistence in Cattle

RODRÍGUEZ, F.M.; GAREIS, N.C.; HEIN, G.J.; SALVETTI, N.R.; AMWEG, A.N.; HUBER, E.; STASSI, A.F.; ORTEGA, H.H.; REY, F.

JOURNAL OF COMPARATIVE PATHOLOGY

ELSEVIER SCI LTD

Año: 2017 vol. 157 p. 201 - 214

0021-9975

Cystic ovarian disease (COD) is one of the main causes of infertility in dairy cattle. It has been postulated thatthe insulin-like growth factor (IGF) system may contribute to follicular persistence and development of COD.The initiation of the IGF response is a result of interactions between IGF-binding proteins (IGFBPs) andIGFBP proteases, mainly pregnancy-associated plasma protein A (PAPP-A). IGFBPs bind IGFs with high affinityand consequently regulate their access to IGF receptors (IGFRs). The aim of this research was to determinevariations in components of the IGF system in the ovaries of cows with persistent follicles induced by longtermadministration of progesterone. Proteins of the IGF system were evaluated at 0 (expected day of ovulation),5, 10 and 15 days of follicular persistence to determine whether the changes occur early in the developmentof COD. The concentrations of IGF1 and IGFBP4 in follicular fluid were similar in all groups withfollicular persistence and in control antral follicles. IGFR1 and IGFBP4 expression in situ were higher in granulosecells in persistent follicles than in control follicles. No differences were found in PAPP-A concentrationwithin follicular fluid in persistent follicles relative to control antral follicles. These data support the hypothesisthat the IGF system is altered in the initial stages of development of follicular persistence and has a determinantrole in ovarian function in cattle.