DRD2 and obesity due to melanocortin 4 receptor deficiency: To explain sulpiride-induced reduced hyperglycemia, it is possible that surplus dopamine—generated by sulpiride occupation of dopamine D2 receptors—elicits a decrease in glucose levels, as reports have shown that administering a high dose of dopamine decreases systemic glucose levels in rats [44] and that dopaminergic tone is reduced in obesity [45–47].