LEAP2 and obesity due to melanocortin 4 receptor deficiency: β-Hydroxybutyrate has been postulated to directly lower plasma LEAP2 through hepatic action, via studies examining effects on LEAP2 secretion from murine hepatocytes ex vivo, while ketogenic diets and exogenous ketone administration lowered plasma LEAP2 in animal studies and in men without obesity [44, 50], though the opposite effect on plasma LEAP2 was seen in another study of exogenous ketone administration in men without obesity [49].