Hepatic stearoyl-CoA desaturase-1 deficiency protects mice from carbohydrate-induced adiposity and hepatic steatosis

Abstract

Stearoyl-CoA desaturase-1 (SCD1), a critical regulator of energy metabolism, catalyzes the synthesis of monounsaturated fats. To understand the tissue-specific role of SCD1 in energy homeostasis, we used Cre-lox technology to generate mice with a liver-specific knockout of Scd1 (LKO). LKO mice were protected from high-carbohydrate, but not high-fat (HF), diet-induced adiposity and hepatic steatosis. Additionally, on a high-sucrose, very low-fat (HSVLF) diet, lipogenesis and levels of nuclear SREBP-1 and ChREBP were significantly decreased in the livers of LKO relative to Scd1(lox/lox) (Lox) mice. HSVLF feeding in LKO mice caused hypoglycemia and hepatic carbohydrate reduction due to an impairment of gluconeogenesis. Oleate, but not stearate, supplementation normalized adiposity, gluconeogenesis, triglyceride secretion, and hepatic lipogenesis of LKO mice. These results indicate that hepatic SCD1 expression (and thus, oleate) is required for carbohydrate-induced adiposity, but SCD1 inhibition in extrahepatic tissues is required to protect mice from HF-induced obesity and insulin resistance.