Progestrone;孕酮;57-83-0 Formula:C21H30O2 Progesterone is an endogenous steroid hormone involved in the menstrual cycle, pregnancy, and embryogenesis of humans and other species. A potent agonist of the nuclear progesterone receptor (nPR) with Kd of 1 nM; An agonist of the membrane progesterone receptors(mPRs); An antagonist of the σ1 receptor.