Characterization of estrone hydroxylase activities in porcine endometrial cells.
The oxidation of estradiol to estrone in porcine endometrial cells is succeeded by hydroxylation at either 6 alpha- or 7 alpha-. The products are devoid of receptor affinity. Their formation is inhibited by cytochrome P450 blockers like ketoconazol but not by chloroquine and analogues. The hydroxylation at 6 alpha- proceeds with KM = 1.9 x 10(-7) M, that at 7 alpha- with KM = 3.6 x 10(-7) M. The respective values for the cytochrome P450-reductase cosubstrate NADPH are 1.7 x 10(-5) M and 1.9 x 10(-5) M. The kinetic parameters of the enzymes are compatible with a metabolic sequence: estradiol-->estrone--> 6 alpha/17 alpha-estrone.
Adamski
J
J
Max-Planck-Institut für experimentelle Endokrinologie, Hannover, Germany.
Hohls
E
E
Jungblut
P W
PW
D000429:Alcohol Oxidoreductases / Q000378:metabolism*; D000818:Animals; D002458:Cell Fractionation; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000502:physiology; D004717:Endometrium / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D004970:Estrone / Q000378:metabolism*; D005260:Female; D006863:Hydrogen-Ion Concentration; D006900:Hydroxylation; D007654:Ketoconazole / Q000494:pharmacology; D008861:Microsomes / Q000201:enzymology; D013379:Substrate Specificity; D013552:Swine
D065607:Cytochrome P-450 Enzyme Inhibitors; D004970:Estrone; D003577:Cytochrome P-450 Enzyme System; D000429:Alcohol Oxidoreductases; C060892:estrone reductase; D007654:Ketoconazole