Influence of genetic variation in alcohol and aldehyde dehydrogenase on serotonin metabolism

The influence of genetic variation in alcohol dehydrogenase (ADH; EC 1.1.1.1) and aldehyde dehydrogenase (ALDH; EC 1.2.1.3) on the metabolic pattern of serotonin (5-hydroxytryptamine, 5-HT) in humans was examined from the relative urinary concentrations of the end products 5-hydroxyindole-3-acetic acid (5-HIAA) and 5-hydroxytryptophol (5-HTOL). Healthy Caucasian (Swedish) and Oriental (Chinese) subjects were genotyped for ADH2, ADH3 and ALDH2 by a PCR/SSCP technique. The 5-HTOL/5-HIAA ratios ranged between 0.9-9.4 pmol/nmol (4.4 +/- 1.8, mean +/- SD, n = 143). No significant difference in the 5-HT metabolic pattern was observed between Caucasians and Orientals (4.3 +/- 1.8 and 4.4 +/- 1.8 pmol/nmol, respectively), nor between any of the ADH2, ADH3 and ALDH2 genotypes. Despite the modulatory effects of genetic variation of these enzymes on ethanol metabolism, the present results indicate that the individual isozyme composition of ADH2, ADH3 and ALDH2 is not important for the metabolic pattern of 5-HT.