CHGA and obesity due to melanocortin 4 receptor deficiency: The role of CST on metabolism came from a study in Chga‐KO mice, which are deficient in CST and PST and display obesity on a normal chow diet.40 Chronic hCST treatment was shown to decrease plasma triglyceride levels in Chga‐KO mice, which is believed to be due to increased lipolysis as evident from increased plasma glycerol and nonesterified fatty acids.40 This effect was mediated through inhibition of α2‐adrenergic receptor (α2‐AR) signaling.