Growth factors and folliculogenesis in polycystic ovary patients.

Ovarian folliculogenesis is regulated by a fine balance between endocrine and intraovarian factors. In this review, we focus on the role of growth factors in physiological folliculogenesis and in polycystic ovaries. Recent evidence shows that the main systems implicated in polycystic ovary folliculogenesis are the growth hormone and insulin-like growth factor system, vascular endothelial growth factor, and the transforming growth factor-β family. Growth hormone and the insulin-like growth factor system could affect follicular development and oocyte maturation if their balance was altered, while vascular endothelial growth factor is implied in follicular dominance by providing an increasing vascular supply. The transforming growth factor-β family is composed of various molecules, which have different roles in cellular proliferation. Finally, a series of different factors seem to be involved in altered polycystic ovary follicular growth.