ITPR1 and obesity due to melanocortin 4 receptor deficiency: By knocking down IP3R (inositol 1,4,5-trisphosphate receptor) in adult drosophila, Subramanian M et al. [26] demonstrated that the loss of the IP3 receptor function in neuropeptide secreting neurons could cause obesity, which is associated with the dysregulation of lipid metabolism.