INS and obesity due to melanocortin 4 receptor deficiency: In a murine model, 4-PBA was demonstrated to resolve fatty liver disease with a decrease in liver triglyceride content and normalization of the liver functional enzymes alanine aminotransferase and aspartate with treatment, in addition to restoring systemic insulin sensitivity and enhancing insulin action in adipose tissues, liver, and muscle of mice with obesity-induced lipid accumulation in the liver (Özcan et al., 2006).