Kinetic Analysis of Reversible Inhibition of 16.ALPHA.-Hydroxyandrostenedione Aromatization in Human Placental Microsomes by Suicide Substrates of Androstenedione Aromatization
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چکیده
منابع مشابه
Utilization of oxygen and reduced nicotinamide adenine dinucleotide phosphate by human placental microsomes during aromatization of androstenedione.
The addition of androstenedione and NADPH to human placental microsomes results in a marked increase in the rate of 0 2 and NADPH utilization concomitant with estrogen formation. Initially, 5 to 12 moles of O2 and an equivalent amount of NADPH are consumed per mole of estrogen formed, the ratio varying from one microsomal preparation to another. In the presence, however, of 10 to 20 mM KCN, 3 m...
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In the stallion testis, aromatase activity was localized in the microsomal fraction. Androgen aromatization occurred through the loss of 1 beta,2 beta hydrogen atoms and appeared to involve free sulfhydryl groups. A single enzyme system seemed to aromatize androgen and norandrogen at the same rate while having a much lower affinity for norandrogens.
متن کاملThe involvement of human placental microsomal cytochrome P-450 in aromatization.
The aromatization of androstenedione is inhibited in the presence of aminoglutethimide, diethylaminoethyl-2,2-diphenyl valerate HCl (SKF 525-A), and 1W3 M KCN, but not carbon monoxide or metyrapone. The role of cytochrome P-450 in this reaction could not, therefore, be unequivocally established by inhibition studies. However, it was determined that steroid binding to placental microsomal cytoch...
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Whereas mare corpus luteum does not produce androgens or estrogens in vivo, the incubation of mare corpus luteum microsomes with progesterone and NADPH resulted in 17 alpha-hydroxyprogesterone and estrogen production with a small yield of androstenedione. In the presence of an aromatase inhibitor (4-hydroxyandrostenedione), 17 alpha-hydroxyprogesterone and androstenedione were accumulated. Arom...
متن کاملPlacental Microsomes
In order to study the initial as well as the final steps in the aromatization of androgens to estrogens, highspecific activity [ 19-CSHs]androstenedione and testosterone were synthesized. Incubations of [ 19-CSHs]androstenedione with human placental microsomes resulted in the generation of [‘Hlwater, as a result of the dual hydroxylation at (2-19, and [’Hlformic acid reflecting final aromatizat...
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ژورنال
عنوان ژورنال: Biological and Pharmaceutical Bulletin
سال: 2003
ISSN: 0918-6158,1347-5215
DOI: 10.1248/bpb.26.890