Downregulation of islet hormone-sensitive lipase during long-term high-fat feeding

Lipid accumulation in pancreatic beta-cells during high-fat (HF) feeding may be involved in inducing a defective insulin secretion due to lipotoxicity. Hormone-sensitive lipase (HSL) is expressed and active in beta-cells, but its importance for islet dysfunction during the development of type 2 diabetes is not known. In this study, prolonged HF feeding of C57BL/6J mice, resulted in decreased HSL expression in islets, representing only 25+/-4% of the levels observed in controls. This was paralleled by triglyceride accumulation and blunted insulin secretion both in vivo and in vitro. After switching the HF diet to a LF diet, HSL expression increased 10-fold compared to the HF fed mice. This was accompanied by reduced triglyceride levels and a restored insulin secretion. These results support the notion that HSL plays a critical role in the regulation of intracellular triglyceride levels in beta-cells, and that downregulation of the enzyme may serve to protect against fatty acid-induced islet dysfunction.