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In vitro inhibition of aromatase by the enantiomers of aminoglutethimide and analogs
Author(s) -
Ogbunude Patrick O.J.,
AboulEnein Hassan Y.
Publication year - 1994
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/chir.530060804
Subject(s) - aminoglutethimide , chemistry , aromatase , androstenedione , microsome , estrone , enantiomer , in vitro , enzyme , michaelis–menten kinetics , chromatography , stereochemistry , enzyme assay , medicine , biochemistry , hormone , androgen , cancer , breast cancer
The in vitro aromatase activity in microsomal fractions from rat ovary and its inhibition by enantiomers of aminoglutethimide (AG), rogletimide (RG), and cyclohexylaminoglutethimide (ChAG) were studied by analysing the [ 3 H]H 2 O released when [1β‐ 3 H]androstenedione was converted to estrone. Maximum velocity ( V max ) and the Michaelis‐Menten constant ( K m ) of the microsomal aromatase enzyme were 17.40 ± 0.45 pmol/ml/mg protein/min and 1.02 ± 0.06 μ M , respectively. The IC 50 s for the enantiomers were similar for (+)‐R‐AG and (−)‐R‐ChAG (0.86 ± 0.06 and 0.89 ± 0.15 μ M , respectively). (+)S‐ChA'G was most potent with IC 50 of 0.075 ± 0.003 μ M . The IC 50 s for (−)‐S‐AG, (+)‐R‐RG, and (−)‐S‐RG were in the same range (23.15 ± 2.74, 24.58 ± 2.46, and 24.43 ± 2.20 μ M , respectively). © 1994 Wiley‐Liss, Inc.