Browsing Pathways

Progesterone is an endogenous steroid hormone that is commonly produced by the adrenal cortex as well as the gonads, which consist of the ovaries and the testes. Progesterone is also secreted by the ovarian corpus luteum during the first ten weeks of pregnancy, followed by the placenta in the later phase of pregnancy. The conversion of progesterone generation from the corpus luteum to the placenta generally occurs after week ten. The molecule progesterone is a derivative of cholesterol and has numerous functions in the human body, especially within the reproductive system. Molecules of progesterone form from the process of steroidogenesis. Progesterone plays a vital role in the maintenance of the uterus during pregnancy. A progestogen (also called progestagen, gestagen, or gestogen) is a molecule, either natural or synthetic, that shows similar effects as progesterone, binds to the progesterone receptor and acts as an agonist. Progestins are synthetic progestogens. Progesterone utilizes intracellular receptors for their mode of action. Progesterone crosses the membrane of a target cell readily by passive diffusion through the plasma membrane due to its lipophilicity and then binds to and activate progesterone receptors. When unbound, the progesterone receptor exists as a monomer. After binding progesterone, the receptor undergoes a conformational change and becomes a dimer, which increases receptor binding to DNA. Most progestins exert their contraceptive effects by suppressing the secretion of gonadotropin-releasing hormone (GnRH) by the hypothalamus and luteinizing hormone (LH) and follicle-stimulating hormone (FSH) by the pituitary gland. This suppression alters the menstrual cycle to suppress ovulation. This progesterone and receptor complex then transports to the nucleus and binds to DNA, specifically near the promoter regions of genes that contain enhancers, containing hormone response elements. This binding of the complex to the promoter can either enhance or repress transcription, which ultimately alters the production of proteins.