Progesterone The major progestational steroid that is secreted primarily by the CORPUS LUTEUM and the PLACENTA. Progesterone acts on the UTERUS, the MAMMARY GLANDS and the BRAIN. It is required in EMBRYO IMPLANTATION, PREGNANCY maintenance, and the development of mammary tissue for MILK production. Progesterone, converted from PREGNENOLONE, also serves as an intermediate in the biosynthesis of GONADAL STEROID HORMONES and adrenal CORTICOSTEROIDS.
[progesterone (Science: biochemistry, gynaecology) Produced in the corpus luteum, as an antagonist of oestrogens. Promotes proliferation of uterine mucosa and the implantation of the blastocyst, prevents further follicular development.
[1. An antiestrogenic steroid, believed to be the active principle of the corpus luteum, isolated from the corpus luteum and placenta or synthetically prepared; used to correct abnormalities of the menstrual cycle, as a contraceptive, and to control habitual abortion.