ESAM and obesity due to melanocortin 4 receptor deficiency: Among the two distinct populations of Kupffer cells mentioned above, i.e., a major CD206lo ESAM- population (KC1) and a minor CD206high ESAM+ population (KC2), only KC2-expressing genes are involved in liver metabolism regulation, including fatty acid metabolism both in steady-state and in diet-induced obesity in mice, as well as steatosis induction via the fatty acid transporter CD36 [52].