RBP4 and Insulin resistance: Additionally, retinol binding protein (RBP) plays a vital role in maintaining serum levels of vitamin A. Elevated serum RBP levels are associated with higher BP, serum triglyceride levels, BMI and insulin resistance (27, 28). A basic experiment showed similar results that the number of RBP4 variants was related to a higher risk of hypertriglyceridemia (29).