Rat ventral prostate xanthine oxidase bioactivation of ethanol to acetaldehyde and 1-hydroxyethyl free radicals: Analysis of its potential role in heavy alcohol drinking tumor-promoting effects

The ability of the ventral prostate cytosolic fractions to biotransform eth anol to acetaldehyde and l-hydroxyethyl (1HEt) radicals was tested. Acetald ehyde formation was determined by GC-FID analysis in the head space of incu bation mixtures. 1HEt was determined by spin trapping with PEN followed by extraction, silylation of the adduct and GC-MS of the product. Prostate cyt osol was able to biotransform ethanol to acetaldehyde in the presence of NA DH, hypoxanthine, xanthine, caffeine, theobromine, theophylline, and 1,7-di methylxanthine but not in the presence of N-methylinicotinamide. All these biotransformations were inhibited by allopurinol and were sensitive to heat ing for 5 min at 100 degreesC. The biotransformation of ethanol to acetalde hyde in the presence of purines as cosubstrates was accompanied by the form ation of hydroxyl and 1HEt radicals as detected by GC-MS, and the process w as inhibited by allopurinol. Results suggest that prostate cytosolic xanthi ne oxidase is able to bioactivate ethanol to acetaldehyde and free radicals . The potential of these processes to be involved in tumor-promoting effect s of heavy alcohol drinking in conjunction with high meat and/or purines co nsumption is analyzed. Multifactorial epidemiological studies considering t hat possibility might be convenient. (C) 2001 Wiley-Liss, Inc.