Progesterone
Progesterone (abbreviated as P4), also known as pregn-4-ene-3,20-dione, is an endogenous steroid and progestogen sex hormone involved in the menstrual cycle, pregnancy, and embryogenesis of humans and other species. It belongs to a group of steroid hormones called the progestogens, and is the major progestogen in the body. Progesterone is also a crucial metabolic intermediate in the production of other endogenous steroids, including the sex hormones and the corticosteroids, and plays an important role in brain function as a neurosteroid.
It is on the WHO Model List of Essential Medicines, the most important medications needed in a basic health system.
Function
Activity profile
Progesterone is the most important progestogen in the body, the result of its action as a potent agonist of the nuclear progesterone receptor (nPR) (with an affinity of KD = 1 nM). In addition, progesterone is an agonist of the more recently discovered membrane progesterone receptors (mPRs), as well as a ligand of the PGRMC1 (progesterone receptor membrane component 1; formerly known as the σ2 receptor). Moreover, progesterone is also known to be an antagonist of the σ1 receptor, a negative allosteric modulator of the nACh receptors, and a potent antagonist of the mineralocorticoid receptor (MR). Progesterone prevents MR activation by binding to this receptor with an affinity exceeding even those of aldosterone and glucocorticoids such as cortisol and corticosterone, and produces antimineralocorticoid effects, such as natriuresis, at physiological concentrations. In addition, progesterone binds to and behaves as a partial agonist of the glucocorticoid receptor (GR), albeit with very low potency (EC50 >100-fold less relative to cortisol).
