FGF21 and Insulin resistance: On the other hand, our recent studies demonstrated that expression of hepatic FGF21 and Sdf2l1 is increased in insulin-resistant C57BL6J mice fed a high-fat diet for 13 days, and that the suppression of hepatic FGF21 and Sdf2l1 expression induced by whey protein insolate decreases insulin resistance and hyperglycemia in C57BL6J mice fed a high-fat diet [16].