Changes of peripheral alpha-melanocyte-stimulating hormone in childhood obesity

Relationships of blood circulating melanocortins to childhood obesity are not well established. We evaluated serum I?-melanocytea??stimulating hormone ( alpha -MSH) in lean children and different study groups of childhood obesity. We examined serum alpha -MSH in 52 otherwise healthy children with childhood obesity (Ob; mean age, 11 years; 32 girls/20 boys), 27 normal-weight children of same age, 7 additional obese patients with reduced melanocortin-4 receptor function MC4Rmut), and 22 patients with craniopharyngioma (CP). Fasting serum alpha d leptin were measured by radioimmunoassay. Serum I?-MSH was also evaluated 1 hour after 500-kcal liquid meal (CP and Ob) and at the end of 1-year lifestyle intervention in 24 Ob patients. The alpha -MSH levels were similar in obese vs lean children but significantly lower in CP (Pb .001) and significantly higher (P b .05) in MC4Rmut patients compared with Ob. One hour after liquid meal, alpha -MSH increased in patients with Ob but not with CP. After 1 year, alpha -MSH levels increased significantly in the successful weight reduction Ob subgroup despite unchanged cortisol levels. The alpha -MSH changes correlated to weight status changes (r = 0.67, P = .0003) but not to changes of cortisol, insulin, or homeostasis model assessment of insulin resistance index. Persistently low alpha -MSH levels in CP patients are suspected to be due to pituitary or hypothalamic damage. High peripheral levels in MC4Rmut carriers indicate up-regulation of alpha -MSH. Changes of weight status are associated with changes of peripheral alpha -MSH.