Central melanocortin pathways have been implicated in the regulation of energy balance and glucose homeostasis. However, little is known about the role of peripheral melanocortin peptides, particularly alpha-melanocyte stimulating hormone (α-MSH). Here, we demonstrate that constant intravenous infusion of different doses of α-MSH during glucose tolerance test (GTT) increases glucose disposal in conscious and unrestrained lean mice (AUC: 0.001μg/h p<0.01; 0.01μg/h p<0.01; 0.1μg/h p<0.05; 1μg/h p<0.01) and the effect is abrogated in diet-induced obese (DIO) mice. Intriguingly, during hyperinsulinemic-euglycemic clamp α-MSH treated lean mice require significantly higher glucose infusion rate (saline vs. α-MSH: 50.76±3.9 vs. 65.87±2.6 mg/kg/min p<0.01) to maintain euglycemia. In addition, whole body Rd is markedly increased in lean mice given α-MSH (saline vs. α-MSH: 46.89±3.8 vs. 60.13±3.7 mg/kg/min p<0.05), which suggests a possible action of α-MSH on skeletal muscle. We also found that α-MSH has an additive effect to insulin-mediated glucose disposal (saline vs. α-MSH: 18.96±4.8 vs. 32.84±2.0 mg/kg/min p<0.05), indicating that the two mechanisms towards glucose uptake in skeletal muscles are distinctly different. Whole-body glucose uptake identifies skeletal muscle as the only target of α-MSH-mediated glucose disposal (saline vs. α-MSH, gastrocnemius: 2.76±0.72 vs. 5.07±0.43 µmol/100g.min p<0.05, soleus: 6.06±0.78 vs. 9.06±1.01 µmol/100g.min p<0.05). Importantly, these changes are independent of hepatic glucose production. Moreover, we show that MC5R, but not other subtypes are highly expressed in skeletal muscle and α-MSH-mediated glucose disposal is completely abolished in MC5R KO mice. Also, lean mice given either neutralizing antibody against α-MSH or selective MC5R antagonist are rendered glucose intolerant relative to vehicle group after glucose challenge. Interestingly, the failure of α-MSH-mediated glucose disposal in DIO mice is a consequence of elevated phosphodiesterase (PDE)4B expression in the soleus (Lean vs. DIO p<0.05). However, by blocking PDE activity with 5 days pretreatment of selective (Rolipram + Saline vs. Rolipram + α-MSH, AUC, p<0.05) and non-selective PDE inhibitors (Vehicle + α-MSH vs. Theophylline + α-MSH, AUC, p<0.01), we restore α-MSH-induced glucose disposal in DIO mice during GTT. To this end, we have identified a novel, insulin-independent and disease-relevant endocrine circuit that regulates peripheral glucose homeostasis.