Serum mitochondrial aspartate aminotransferase activity: Not useful as a marker of excessive alcohol consumption in an unselected population

Abstract

Using an immunochemical method, we measured the activity of the mitochondrial isoenzyme (mAST) of aspartate aminotransferase (EC 2.6.1.1, AST) in the serum of 687 subjects attending the Centre for Preventive Medicine for a health examination. The distributions of the activities were asymmetrical, with mean values of 1.8 U/L (SD 2.0) for men and 1.4 U/L (SD 1.6) for women. The average ratio of mitochondrial to total AST activity was 0.051 (range 0-0.42). In this unselected population we found no change in the mitochondrial activity or in the mitochondrial-to-total ratio attributable to alcohol consumption, even in subjects who consumed more than 88 g per day. Of 35 men with an alcohol consumption >88 g/d, 19 had a serum γ-glutamyltransferase activity of ≥60 U/L, 17 had glutamate dehydrogenase values ≥5 U/L, and only nine had an mAST activity ≥3 U/L (values corresponding to the 80th percentiles of the total population). We conclude that the test is not particularly useful as a screening procedure in an unselected population under present-day conditions of measurement.