medroxyprogesterone brands

Molecular formula: C22H32O3

Medroxyprogesterone shares the pharmacologic actions of the progestins. In women with adequate endogenous estrogen, medroxyprogesterone transforms a proliferative endometrium into a secretory one. Medroxyprogesterone has been shown to have slight androgenic activity in animals. Anabolic effects have also been reported, but the drug apparently lacks appreciable estrogenic activity in humans. In animals, the drug exhibits pronounced adrenocorticoid activity, but a clinically important effect has not been observed in humans. Medroxyprogesterone inhibits the secretion of pituitary gonadotropins following usual IM or subcutaneous dosages (eg, 150 or 104 mg every 3 months), thus preventing follicular maturation and ovulation and resulting in endometrial thinning; these effects result in contraceptive activity. Available evidence indicates that these effects do not occur following oral administration of usual dosages (ie, 5-10 mg daily as single daily doses) of the drug. High doses of medroxyprogesterone inhibit pituitary secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), and will prevent cyclic gonadotropin surges that occur during the normal menstrual cycle. It has been suggested that the drug acts at the hypothalamus since it does not suppress the release of LH and FSH following administration of gonadotropin-releasing hormone and since basal concentrations of LH and FSH remain within the low normal range when the drug is used as a contraceptive. Although the mechanism of action has not been determined, medroxyprogesterone has antineoplastic activity against some cancers (eg, endometrial carcinoma, renal carcinoma). Progestins elicit, to varying degrees, all the pharmacologic responses usually produced by progesterone: induction of secretory changes in the endometrium, increase in basal body temperature (thermogenic action), production of histologic changes in vaginal epithelium, relaxation of uterine smooth muscle, stimulation of mammary alveolar tissue growth, pituitary inhibition, and production of withdrawal bleeding in the presence of estrogen. /Progestins/ Following binding to cytoplasmic receptor protein, steroid is transported to nucleus, and complex is bound there in reactions analogous to those described... for estrogens. However, there is no apparent need for receptor alteration, as with estrogen receptor. /Progesterone/ Although medroxyprogesterone acetate (MPA) is used as an injectable contraceptive, in hormone replacement therapy (HRT) and in treatment of certain cancers, the steroid receptors and their target genes involved in the actions of MPA are not well understood. /Investigators/ show that MPA, like dexamethasone (dex), significantly represses tumour necrosis factor (TNF)-stimulated interleukin-6 (IL-6) protein production in mouse fibroblast (L929sA) cells. In addition, MPA repressed IL-6 and IL-8 promoter-reporter constructs at the transcriptional level, via interference with nuclear factor kappaB (NFkappaB) and activator protein-1 (AP-1). Furthermore, like dex, MPA does not affect NFkappaB DNA-binding activity. /The authors/ also observed significant transactivation by MPA of a glucocorticoid response element (GRE)-driven promoter-reporter construct in both L929sA and COS-1 cells. The MPA-induced nuclear translocation of the glucocorticoid receptor (GR), as well as the antagonistic effects of RU486, strongly suggest that the actions of MPA in these cells are mediated at least in part via the GR. /Investigators/ assessed the transcriptional effects of MPA as compared with those of progesterone and dihydrotestosterone (DHT) in human breast cancer cells. A new progesterone receptor-negative, androgen receptor-positive human breast cancer cell line, designated Y-AR, was engineered and characterized. Transcription assays using a synthetic promoter/reporter construct, as well as endogenous gene expression profiling comparing progesterone, MPA and DHT, were performed in cells either lacki

Source: PubChem (NCBI) · compound 10631