Levonorgestrel

Description: Levonorgestrel is a potent female hormone that prevents ovulation and therefore used in a number of birth control methods. Levonorgestrel is a synthetic progestin that binds to progesterone and androgen receptors but not the estrogen receptor. It induces apoptosis in ovarian epithelium cells. Levonorgestrel suppresses the stimulation of progesterone secretion induced by oLH, dibutyryl-cAMP and Pregnenolone in rats luteal cells. Levonorgestrel also inhibits constrictions evoked by either a high potassium (K(+)) solution or phorbol myristate acetate (PMA) in the absence and presence of extracellular calcium (Ca(2+)). Levonorgestrel is useful within 120 hours as emergency birth control. It becomes less effective the longer after sex and only works before pregnancy has occurred. It is also combined with an estrogen to make combined oral birth control pill.

References: J Steroid Biochem Mol Biol. 1994; 50:161-6; Br J Pharmacol. 2000; 130:1911-8; Exp Anim. 2011; 60:363-71.

Related CAS#:13635-16-0 (Levonorgestrel hexanoate); 86679-33-6 (Levonorgestrel butyrate); 39366-37-5 (Ethinylestradiol mixture with Levonorgestrel)