Description
Betatrophin (RIFL; Lipasin; Angiopoietin-like protein 8 (ANGPTL8)) is a newly discovered secreted protein of 198 aa that was proposed to promote beta cell proliferation and improve glucose tolerance in mice. Betatrophin may also function in inhibition of lipase activity and on serum triglyceride regulation. Betatrophin is expressed in the liver and in white and brown adipose tissue of mice. In humans, betatrophin is found to be predominantly expressed in the liver. Betatrophin levels are reduced by fasting and are elevated upon insulin resistance and during pregnancy. Betatrophin, according to preliminary data could bind to the macrophage receptor Marco and also to RTN4R, a neuronal receptor. Recently, a study using ANGPTL8 KO mice showed that ANGPTL8/Betatrophin does not play a role in beta cell proliferation nor in glycemic control as previously thought, but regulates plasma triglyceride levels