GPT and alcohol dependence: According to Kravos et al. [232], GDH is a sensitive biomarker of alcoholism, with levels falling almost immediately after the cessation of drinking, which is much faster than is the case with other known biomarkers such as gamma-glutamyltranspeptidase (GGT), aspartate aminotransferase (AST), alanine aminotransferase (ALT) and mean erythrocyte volume (MCV).