Norelgestromin is an active metabolite of the progestin norgestimate .1 Norelgestromin is formed from norgestimate via deacetylation in human liver microsomes. It is an agonist of the progesterone receptor and estrogen receptor α (ERα; EC50s = 11.1 and 43.4 nM, respectively) and an antagonist of the glucocorticoid and mineralocorticoid receptors (IC50s = 255 nM and 83.7 nM, respectively).2 Norelgestromin selectively binds to progestin receptors (IC50 = 4.61 nM for rabbit uterine receptors) over androgen receptors (IC50 = 222 nM for rat prostatic receptors) in radioligand binding assays.3 However, norelgestromin (1 nM) activates the androgen receptor in a transactivation assay in MDA-MB-231 breast cancer cells expressing the human receptor.4 Formulations containing norelgestromin in combination with ethynyl estradiol have been used as contraceptives and in the treatment of acne vulgaris in women.
1.Madden, S., and Back, D.J.Metabolism of norgestimate by human gastrointestinal mucosa and liver microsomes in vitroJ. Steroid Biochem. Mol. Biol.38(4)497-503(1991) 2.Paris, F., Balaguer, P., Rimbault, F., et al.Molecular action of norgestimate: New developmentsGynecol. Endocrinol.31(6)487-490(2015) 3.Phillips, A., Demarest, K., Hahn, D.W., et al.Progestational and androgenic receptor binding affinities and in vivo activities of norgestimate and other progestinsContraception41(4)399-410(1990) 4.Prifti, S., Lelle, I., Strowitzki, T., et al.Induction of androgen receptor activity by norgestimate and norelgestromin in MDA-MB 231 breast cancer cellsGynecol. Endocrinol.19(1)18-21(2004)