Impaired insulin signaling pathway in ovarian follicles of cows with cystic ovarian disease.

Cystic ovarian disease (COD) is an important cause of infertility in dairy cattle. Follicular cell steroidogenesis and proliferation in ovulatory follicles is stimulated by hormones such as insulin and its necessary post-receptor response. The aim of this study was to determine the expression of insulin receptor (IR), IR substrate-1 (IRS1) and phosphatidylinositol 3-kinase (PI3K), key intermediates in the insulin pathway, in control cows and cows with spontaneous COD and ACTH-induced COD.

Levels of heat shock protein transcripts in normal follicles and ovarian follicular cysts.

In the study, the gene expression of several heat shock proteins (HSPs) was determined in normal follicles and cystic follicles from cattle. A lower expression of HSP10 and HSP40 was observed in granulosa and theca cells of cysts compared to normal follicles. HSP27 was significantly less expressed in granulosa cells in cystic and large antral follicles than in other follicular categories.

Influence of insulin-like growth factor-binding proteins-2 and -3 in the pathogenesis of cystic ovarian disease in cattle.

Ovarian cysts are one of the major causes of infertility in dairy cows. The development is associated with an endocrine imbalance in the hypothalamo-hypophyseal-gonadal axis in which endocrine factors participate in follicular growth and differentiation and in the secretion of ovarian hormones. Insulin-like growth factor family are essential local regulators of ovarian follicle development and functionality and actions are mediated by binding protein activity.

An imbalance between apoptosis and proliferation contributes to follicular persistence in polycystic ovaries in rats.

Background: Cystic ovarian disease is an important cause of infertility that affects bovine, ovine, caprine and porcine species and even human beings. Alterations in the ovarian micro-environment of females with follicular cysts could alter the normal processes of proliferation and programmed cell death in ovarian cells. Thus, our objective was to evaluate apoptosis and proliferation in ovarian cystic follicles in rats in order to investigate the cause of cystic follicle formation and persistence.