The Sound of Evolution
Medroxyprogesterone acetate
醋酸甲羥孕酮
Mechanism of action:
Medroxyprogesterone acetate 是一種合成黃體製劑（synthetic progestin），為孕酮（progesterone）的醋酸酯衍生物。Medroxyprogesterone acetate 與細胞內的孕酮受體（progesterone receptor）結合後，形成配體-受體複合體並進入細胞核，調控特定基因的轉錄，使組織表現出黃體期樣的生理反應。Medroxyprogesterone acetate 會對下視丘與腦下垂體產生負回饋作用，抑制促性腺激素釋放激素（GnRH）、黃體成長激素（LH）與濾泡刺激素（FSH）的分泌，阻止黃體成長激素達到高峰，從而抑制排卵。
Reference(s):
1. Akpoviroro JO et al. (1981). Binding of the contraceptive steroids medroxyprogesterone acetate and ethynyloestradiol in blood of various species. J Steroid Biochem.
2. Johansson ED et al. (1986). Medroxyprogesterone acetate pharmacokinetics following oral high-dose administration in humans: a bioavailability evaluation of a new MPA tablet formulation. Acta Pharmacol Toxicol (Copenh).
3. Sierra-Ramirez JA et al. (2011). Comparative pharmacokinetics and pharmacodynamics after subcutaneous and intramuscular administration of medroxyprogesterone acetate (25 mg) and estradiol cypionate (5 mg). Contraception.