In mammals, oocytes develop inside the ovarian follicles; this process is strongly supported by the surrounding follicular environment consisting of cumulus, granulosa and theca cells, and follicular fluid. In the antral follicle, the final stages of oogenesis require large amounts of energy that is produced by follicular cells from substrates including glucose, amino acids and fatty acids (FAs...

Growth and development of ovarian follicles require a series of coordinated events that induce morphological and functional changes within the follicle, leading to cell differentiation and oocyte development. The preantral early antral follicle transition is the stage of follicular development during which gonadotropin dependence is obtained and the progression into growing or atresia of the fo...

Initiation of folliculogenesis through the induction of primordial follicle development in the ovary has an important role in determining the fertility and reproductive fitness of most mammalian species. The factors that control this critical process are largely unknown. The hypothesis tested in the current study was that kit-ligand/stem cell factor (KL) promotes the initiation and progression ...

Nineteen cycling ewes underwent transrectal ultrasonography of ovaries followed by ovariectomies during the growth phase of the first follicular wave of the interovulatory interval or the proestrus/estrus phase of the cycle. Quantitative ultrasonographic characteristics of the antrum and follicular wall in a total of forty-three ovine antral follicles were examined for correlations with the pro...

The effects of catecholamines and ascorbic acid on cultured bovine granulosa cells have been examined to assess their possible role in the initiation and maintenance of luteal oxytocin secretion. The actions of these agents have also been compared with the previously reported ability of follicular theca tissue to enhance oxytocin secretion. Using granulosa cells cultured in serum-supplemented m...

We have observed that levels of the antioxidant glutathione (GSH) and protein levels of the catalytic and modifier subunits of the rate-limiting enzyme in GSH synthesis, GCLc and GCLm, increase in immature rat ovaries after treatment with gonadotropin. The goals of the present studies were to delineate the time course and intraovarian localization of changes in GSH and GCL after PMSG and after ...

Angiogenic factors are associated with angiogenesis during follicular development in the mammalian ovary. The aim of the present study was to determine the relationships between the vascular network and mRNA expressions of angiopoietins (Ang)-1, Ang-2 and hepatocyte growth factor (HGF), and their receptors in follicles at different developmental stages during follicular development. Ovaries in ...

BACKGROUND Neovascularization is necessary for follicular growth. Vascularization is first observed in preantral follicles, and thereafter the vasculature markedly increases in follicles undergoing development. Neovascularization includes angiogenesis and vasculogenesis. Vasculogenesis is the formation of new blood vessels by bone marrow-derived endothelial progenitor cells. It is unclear wheth...