GPT and hepatitis A virus infection: Potential effects of J1/J2 on the liver were further studied by measuring ALT (alanine aminotransferase) and AST (aspartate aminotransferase) levels in the samples, because high levels of ALT and AST are often detected in the blood from individuals with several clinical conditions such as liver damage, alcoholic/nonalcoholic liver injury and hepatitis (11, 12).