title: An Evaluation of Acylated Ghrelin and Obestatin Levels in Childhood Obesity and Their Association with Insulin Resistance, Metabolic Syndrome, and Oxidative Stress.
abstract: BACKGROUND
  Ghrelin is a 28-amino acid peptide with an orexigenic property, which is predominantly produced by the stomach. Acylated ghrelin is the active form of this hormone. Obestatin is a 23-amino acid peptide which is produced by post-translational modification of a protein precursor that also produces ghrelin. Obestatin has the opposite effect of ghrelin on food intake. The aim of this study was to evaluate acylated ghrelin and obestatin levels and their ratio in obese and normal-weight children and adolescents, and their association with metabolic syndrome (MetS) parameters.
  
  
  METHODS
  Serum acyl-ghrelin, obestatin, leptin, insulin, fasting plasma glucose (FPG), lipid profile, and malondialdehyde (MDA) were evaluated in 73 children and adolescents (42 obese and 31 control). Insulin resistance was calculated by a homeostasis model assessment of insulin resistance (HOMA-IR). MetS was determined according to IDF criteria.
  
  
  RESULTS
  Acyl-ghrelin levels were significantly lower in obese subjects compared to the control group and lower in obese children with MetS compared to obese subjects without MetS. Obestatin was significantly higher in obese subjects compared to that of the control, but it did not differ significantly among those with or without MetS. Acyl-ghrelin to obestatin ratio was significantly lower in obese subjects compared to that in normal subjects. Acyl-ghrelin showed significant negative and obestatin showed significant positive correlations with body mass index (BMI), BMI Z-score, leptin, insulin, and HOMA-IR. Acyl-ghrelin had a significant negative correlation with MDA as an index of oxidative stress.
  
  
  CONCLUSIONS
  Ghrelin is decreased and obestatin is elevated in obesity. Both of these hormones are associated with insulin resistance, and ghrelin is associated with oxidative stress. The balance between ghrelin and obestatin seems to be disturbed in obesity.
authors.affiliation: Metabolic Disorders Research Center, Endocrinology and Metabolism Molecular-Cellular Sciences Institute, Tehran University of Medical Sciences, 1411715851 Tehran, Iran. mrazar@tums.ac.ir.|H. Aliasghar Hospital, Iran University of Medical Sciences, 1449614535 Tehran, Iran. mrazar@tums.ac.ir.
authors.forename: Maryam
authors.initials: M
authors.lastname: Razzaghy-Azar
authors.affiliation: Department of Biochemistry, School of Medicine, Iran University of Medical Sciences, 1449614535 Tehran, Iran. Nourbakhsh.m@iums.ac.ir.
authors.forename: Mitra
authors.initials: M
authors.lastname: Nourbakhsh
authors.affiliation: H. Aliasghar Hospital, Iran University of Medical Sciences, 1449614535 Tehran, Iran. a_p_808@yahoo.com.
authors.forename: Abdolreza
authors.initials: A
authors.lastname: Pourmoteabed
authors.affiliation: H. Aliasghar Hospital, Iran University of Medical Sciences, 1449614535 Tehran, Iran. dr.mnrbh@yahoo.com.
authors.forename: Mona
authors.initials: M
authors.lastname: Nourbakhsh
authors.affiliation: Department of Biochemistry, School of Medicine, Tehran University of Medical Sciences, 1417614418 Tehran, Iran. ildavod@yahoo.com.
authors.forename: Davod
authors.initials: D
authors.lastname: Ilbeigi
authors.affiliation: Department of Biochemistry, School of Medicine, Iran University of Medical Sciences, 1449614535 Tehran, Iran. dara1khosravi@gmail.com.
authors.forename: Mohsen
authors.initials: M
authors.lastname: Khosravi
keywords: ghrelin; insulin resistance; metabolic syndrome; obesity; obestatin; oxidative stress