title: Alpha-Melanocyte-Stimulating Hormone and Agouti-Related Protein: Do They Play a Role in Appetite Regulation in Childhood Obesity?
abstract: OBJECTIVE
  The hypothalamus plays a crucial role in the regulation of feeding behavior. The anorexigenic neuropeptide alpha-melanocyte-stimulating hormone (α-MSH) and the orexigenic neuropeptide agouti-related protein (AgRP) are among the major peptides produced in the hypothalamus. This study investigated the plasma concentrations of α-MSH and AgRP in underweight and obese children and their healthy peers. The associations between α-MSH and AgRP levels and anthropometric and nutritional markers of malnutrition and obesity were also assessed.
  
  
  METHODS
  Healthy sex-matched subjects aged 2 to 12 years were divided into 3 groups, as underweight (n=57), obese (n=61), and of normal weight (n=57). Plasma fasting concentrations of α-MSH and AgRP were measured by enzyme-linked immunosorbent assay. The differences between the three groups as to the relationships between plasma concentrations of α-MSH and AgRP and anthropometric data, serum biochemical parameters and homeostatic model assessment of insulin resistance were evaluated.
  
  
  RESULTS
  Obese children had significantly lower α-MSH levels than underweight (1194±865 vs. 1904±1312 ng/mL, p=0.006) and normal weight (1194±865 vs. 1762±1463 ng/mL, p=0.036) children; there were no significant differences in the α-MSH levels between the underweight and normal weight children (p=0.811). Also, no significant differences were observed between the underweight and obese children regarding the AgRP levels (742±352 vs. 828±417 ng/mL, p=0.125). We found a significant positive correlation between plasma α-MSH and AgRP levels across the entire sample.
  
  
  CONCLUSIONS
  This study is the first to demonstrate body weight-related differences in α-MSH and AgRP levels in children. Circulating plasma α-MSH levels in obese children were markedly lower than those of underweight and normal-weight children. This suggests that α-MSH could play a role in appetite regulation.
authors.affiliation: Bezmialem Vakıf University Faculty of Medicine, Department of Pediatrics, İstanbul, Turkey, Phone: +90 212 453 17 00 E-mail: ayvahap@hotmail.com.
authors.forename: Aysel
authors.initials: A
authors.lastname: Vehapoğlu
authors.forename: Serdar
authors.initials: S
authors.lastname: Türkmen
authors.forename: Şule
authors.initials: Ş
authors.lastname: Terzioğlu
mesh_terms: D054369:Agouti-Related Protein / Q000097:blood*; D001069:Appetite Regulation / Q000502:physiology*; D015415:Biomarkers / Q000097:blood*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D063766:Pediatric Obesity / Q000503:physiopathology*; D011379:Prognosis; D013851:Thinness; D000521:alpha-MSH / Q000097:blood*
chemical_list: C515198:AGRP protein, human; D054369:Agouti-Related Protein; D015415:Biomarkers; D000521:alpha-MSH