PTEN and fatty liver disease: Circulating aspartate transaminase (AST) and alanine transaminase (ALT) were increased in PTENKO and PTEN-IGF1RKO mice, but not in PTEN-IRKO and triple-KO mice, suggesting that disruption of IR signaling might attenuate hepatic injury associated with PTEN deficiency (Fig. 1F), possibly because of the reduction in hepatic steatosis in these IR-deficient groups.