INS and type 2 diabetes mellitus: Conclusions regarding the effect of kisspeptin1 on beta cells are controversial since increased kisspeptin1 levels in the liver and plasma of both obese mouse models and T2D patients have been described to inhibit insulin secretion [27] whereas placenta-derived kisspeptin1 seems to play a physiological role in the islet adaptation to pregnancy, maintaining maternal glucose homeostasis by acting through the beta-cell GPR54 receptor.