title: Characteristics of estrogen-2/4-hydroxylase in pig blastocysts: inhibition by steroidal and nonsteroidal agents.
abstract: The inhibitory potencies of steroidal and non-steroidal estrogens, catechol-estrogens, methoxyestrogen, haloestrogens, cholesterol and its side-chain-cleaved products, and inhibitors of steroid aromatase against the activity of estradiol-2/4-hydroxylase (E-2/4-H) in pig blastocysts were studied. All tested compounds, except cholesterol and 4-hydroxyandrostenedione, inhibited E-2/4-H in vitro. The fluctuation of E-2/4-H activity in pig blastocysts on different days of pregnancy may be due to the modulation of enzyme activity by steroids in the uterine lumen. Although alpha-naphthoflavone and aminoglutethimide did not affect E-2/4-H activity in vitro, inhibition by CO (95% CO + 5% O2), SKF-525A, piperonyl butoxide, and antibody to cytochrome P-450 reductase provides evidence for the involvement of cytochrome P-450 in E-2/4-H activity in pig blastocysts.
authors.affiliation: Department of Obstetrics and Gynecology, University of Kansas Medical Center, Kansas City 66103.
authors.forename: C
authors.initials: C
authors.lastname: Chakraborty
authors.forename: D L
authors.initials: DL
authors.lastname: Davis
authors.forename: S K
authors.initials: SK
authors.lastname: Dey
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000201:enzymology*; D002784:Cholesterol / Q000494:pharmacology; D019363:Cytochrome P-450 CYP1A1; D065607:Cytochrome P-450 Enzyme Inhibitors; D004054:Diethylstilbestrol / Q000494:pharmacology; D004967:Estrogens / Q000494:pharmacology; D006589:Hexestrol / Q000494:pharmacology; D011284:Pregnenolone / Q000494:pharmacology; D011374:Progesterone / Q000494:pharmacology; D013250:Steroid Hydroxylases / Q000037:antagonists & inhibitors*; D013256:Steroids / Q000494:pharmacology*; D013552:Swine
chemical_list: D065607:Cytochrome P-450 Enzyme Inhibitors; D004967:Estrogens; D013256:Steroids; D006589:Hexestrol; D011374:Progesterone; D004054:Diethylstilbestrol; D011284:Pregnenolone; D002784:Cholesterol; D013250:Steroid Hydroxylases; D019363:Cytochrome P-450 CYP1A1; C020120:estrogen 2-hydroxylase