Health / Medical Topics |
Norethindrone Acetate
Definition 1
The orally bioavailable acetate salt of norethindrone, a synthetic progestin with some anabolic, estrogenic, and androgenic activities. As do all progestins, norethindrone binds to and activates nuclear progesterone receptors (PRs) in target tissues such as the pituitary and reproductive system; ligand-receptor complexes are translocated to the nucleus where they bind to progesterone response elements (PREs) located on target genes, followed by various transcriptional events and histone acetylation. Physiological effects include the inhibition of luteinizing hormone (LH) release, an increase in the endometrial luteal-phase, and alterations in endocervical mucus secretion. (NCI Thesaurus)
Definition 2
A synthetic progestational hormone with actions similar to those of PROGESTERONE but functioning as a more potent inhibitor of ovulation. It has weak estrogenic and androgenic properties. The hormone has been used in treating amenorrhea, functional uterine bleeding, endometriosis, and for contraception. (NLM, Medical Subject Headings)