The detection of A-ring-hydroxylated estrogens and their methyl ethers on ascorbic acid-impregnated paper and thin layer chromatograms

Comparison of cytochrome P-450 species which catalyze the hydroxylations of the aromatic ring of estradiol and estradiol 17-sulfate

For identification of microsomal cytochrome P-450 (P-450) enzymes which catalyze 2- or 4-hydroxylations of estrogens in the rat liver, estradiol (E2) and estradiol 17-sulfate (E2-17-S) were selected as the substrates and incubated with various kinds of purified P-450 enzymes: PB-1, PB-2, PB-4 and PB-5 obtained from phenobarbital-treated male rats (Sprague-Dawley); MC-1 and MC-5 from 3-methylcholanthrene-treated male rats; and UT-1, UT-2, UT-4 and UT-5 from untreated animals. The reactions were carried out under the P-450-reconstructed system, and the resulting products were determined by HPLC using electrochemical detection. All the enzymes tested were shown to have varying degrees of catalytic activities for 2-hydroxylation of the two substrates; UT-1 and UT-2 had the highest activity. Of the induced P-450 enzymes, PB-2 and MC-1 showed fairly high catalytic activity for 4-hydroxylation of E2. The P-450 enzymes obtained from the untreated male rats, especially UT-4, showed the highest catalytic activity for 4-hydroxylation of the two substrates. From these results and also from kinetic experiments, the P-450 enzymes which catalyze 2- and 4-hydroxylations of estrogen were considered to be different species. A part of E2 was converted to such metabolites as estrone and those having a hydroxyl group at positions 6 beta, 15 alpha or 16 alpha, each production of which was estimated to be catalyzed by single or multiple P-450s.

Synthesis of pyrogallolestrogens (2,3,4-trihydroxy-1,3,5(10)-estratrienes) and their methyl ethers

The preparation of 2,4-dihydroxyestrone, 2,4-dihydroxyestradiol-17beta and their methyl ethers (14 compounds) is described. The structures were established by nuclear magnetic resonance, infrared and mass spectra as well as by elemental analyses, microchemical reactions, alternative synthetic routes and by their chromatographic properties.