PTPN1 and obesity due to melanocortin 4 receptor deficiency: Moreover, trodusquemine was shown to suppress appetite and decrease body weight in a highly specific manner in normal and obese rodents,8, 9 by acting specifically and reversibly as a non‐competitive inhibitor of the protein‐tyrosine phosphatase 1B (PTP1B), a negative regulator of insulin and leptin signaling that represents a validated therapeutic target for diabetes and obesity.10, 11