Relationship between the covalent binding of N-acetoxy-2-acetylaminofluorene to DNA and a steroidal esterase activity in human mononuclear leukocytes.
A method for the quantitative assessment of steroidal esterase activity in viable human mononuclear leukocytes (HML) has been developed. It is based on estimating the conversion of [3H]beclomethasone-17,21-dipropionate (BDP) to beclomethasone-17-monopropionate (BMP) using TLC on silica gel 60 F-254 plates developed in a solvent system of chloroform/methanol (97:3, v/v). The cell assay procedure was dependent on BDP concentration, incubation time and cell concentration. The steroidal esterase activity was completed for by N-acetoxy-N-acetyl-2-aminofluorene (NA-AAF) and completely inhibited by 100 microM paraoxon. When [3H]NA-AAF binding to DNA was used as an indicator of HML esterase (deacylase) activity, BDP functioned as a substrate inhibitor. Parallel estimations of BDP metabolism and NA-AAF binding to DNA indicated striking correlations in the interindividual variations (r = 0.62, P less than 0.001) and in relation to the menstrual cycle events of a healthy female. Hence, these data indicate that both BDP and NA-AAF are metabolized by the same non-specific steroidal esterase present in HML.
Lund-Pero
M
M
Division of Biochemical Epidemiology, Preventive Medicine Institute/Strang Clinic, New York, NY 10016.
Pero
R W
RW
Miller
D G
DG
D015073:2-Acetylaminofluorene / Q000031:analogs & derivatives*; D000099:Acetoxyacetylaminofluorene / Q000378:metabolism*; D001507:Beclomethasone / Q000378:metabolism; D002265:Carboxylic Ester Hydrolases / Q000097:blood*; D004247:DNA / Q000378:metabolism*; D005260:Female; D006358:Hot Temperature; D006801:Humans; D007700:Kinetics; D007963:Leukocytes, Mononuclear / Q000201:enzymology*; D008597:Menstrual Cycle; D010261:Paraoxon / Q000494:pharmacology; D002787:Sterol Esterase / Q000097:blood*
D000099:Acetoxyacetylaminofluorene; D004247:DNA; D015073:2-Acetylaminofluorene; D002265:Carboxylic Ester Hydrolases; D002787:Sterol Esterase; D001507:Beclomethasone; D010261:Paraoxon