title: Individual differences in plasma ALT, AST and GGT: contributions of genetic and environmental factors, including alcohol consumption.
abstract: The causes of individuality of the plasma enzymes alanine aminotransferase (ALT; EC 2.6.1.2), aspartate aminotransferase (AST; EC 2.6.1.1) and gamma-glutamyl transferase (GGT; EC 2.3.2.2) were investigated in a study of 206 pairs of twins. Between-person variance was greater in men than women, while within-person variation was similar in both sexes. Plasma ALT and AST levels were affected by genetic factors, while GGT was affected by some environmental factor shared by co-twins. In the men, alcohol intake had a significant but small effect on all three enzyme levels, and since alcohol consumption was highly heritable, this appeared as a genetic influence on enzyme activities. The major factors involved in the observed correlations between these enzymes were a non-shared environmental factor other than alcohol affecting ALT, AST and GGT, and a genetic factor affecting only ALT and AST.
authors.forename: J B
authors.initials: JB
authors.lastname: Whitfield
authors.forename: N G
authors.initials: NG
authors.lastname: Martin
mesh_terms: D000293:Adolescent; D000328:Adult; D000410:Alanine Transaminase / Q000097:blood* / Q000235:genetics; D000428:Alcohol Drinking; D001219:Aspartate Aminotransferases / Q000097:blood* / Q000235:genetics; D004777:Environment; D005260:Female; D014644:Genetic Variation; D006801:Humans; D008297:Male; D011247:Pregnancy; D012737:Sex Factors; D014427:Twins; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic; D005723:gamma-Glutamyltransferase / Q000097:blood* / Q000235:genetics
chemical_list: D005723:gamma-Glutamyltransferase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase