Ovarian Hormones: Structure, Biosynthesis, Function, Mechanism of Action, and Laboratory Diagnosis

Abstract

The ovary is a dynamic endocrine organ. The follicle cells interact in a highly integrated manner to produce several steroid and peptide hormones. Steroidogenesis requires effectual delivery, uptake, and use of sterol by an array of steroidogenic enzymes. Steroid hormones play a central role in the reproductive system. Physiological effects of steroid hormones are mediated via their nuclear receptors that belong to a superfamily of ligand-dependent transcription factors. The two isoforms of ER and PR ($α$ and $β$) are differentially expressed in different tissues, leading to tissue-specific responses. Furthermore, the differences in gene expression depend on interactions with protein cofactors, the coactivators, and corepressors. A better understanding of the effect that the cell environment has on nuclear receptors and their coregulators led to the discovery and understanding of the mechanism of action of antiestrogens and selective receptor modulators.