Cell-based experiments have also shown a similar trend and found that Apelin-13 reduced lipid content and total cholesterol content (14), indicating that amidation-modified Apelin-13 might downregulate the expression of PPARγ, thereby inhibiting the differentiation of adipocytes, resulting in the regulation of PLIN1 expression to promote lipolysis in vivo, which ameliorated obesity symptoms. Here, PPARG is linked to obesity due to melanocortin 4 receptor deficiency.