Obese mice induced by gold thioglucose administration exhibited a different expression profile of hepatic P450s with no significant change in Cyp3a. High-fat diet-induced changes in energy metabolism, which eventually result in obesity, modulate the hepatic expression profile of P450s, particularly Cyp3a [57]. The gene discussed is CYP3A4; the disease is obesity due to melanocortin 4 receptor deficiency.