title: [Metabolism and pharmacokinetics of synthetic estrogens and progestogens].
abstract: Synthetic steroids, having delta 4-3-ketone structure, are commonly metabolised to the corresponding tetrahydro-metabolites. The reduction of the 20-ketone group is also essential for pregnan series progestogens. When these metabolic pathways are obstructed in some way, steroids are hydroxylated at proper positions. Hydroxylation of a steroid is primarily directed to form the inactive form, namely, conjugated steroid. However, in some cases, it induces activation or activity change to the original compound. Activation of lynestrenol, as a progestogen and the conversion of norethindrone to ethynylestradiol, are examples. Metabolism of some new steroids and factors affecting the effect of oral contraceptive pills are discussed.
authors.affiliation: Department of Obstetrics and Gynecology, Kyoto Prefectural University of Medicine.
authors.forename: H
authors.initials: H
authors.lastname: Okada
mesh_terms: D045166:Estradiol Congeners / Q000737:chemistry / Q000378:metabolism / Q000493:pharmacokinetics*; D006801:Humans; D006900:Hydroxylation; D045167:Progesterone Congeners / Q000737:chemistry / Q000378:metabolism / Q000493:pharmacokinetics*
chemical_list: D045166:Estradiol Congeners; D045167:Progesterone Congeners