Branched fatty acid esters of hydroxy fatty acids (FAHFAs) are newly identified endogenous lipids regulated by fasting and high-fat feeding and associated with insulin sensitivity. 5-SAHSA is a FAHFA in which stearic acid is esterified to 5-hydroxy stearic acid. The levels of SAHSA are moderately elevated in the serum of glucose tolerant AG4OX mice, which overexpress the Glut4 glucose transporter specifically in adipose tissue. As other FAHFAs improve glucose tolerance, stimulate insulin secretion, and have anti-inflammatory effects, 5-SAHSA may be a bioactive lipid with roles in metabolic syndrome and inflammation.
