title: Serum Concentrations of Ghrelin and Leptin according to Thyroid Hormone Condition, and Their Correlations with Insulin Resistance.
abstract: BACKGROUND
  Thyroid hormones can influence energy metabolism and insulin sensitivity via their interaction with adipocytokines and gut hormones. The aims of this study were to evaluate differences in serum ghrelin and leptin concentrations according to thyroid hormone levels, and to investigate the correlation of insulin resistance.
  
  
  METHODS
  A total of 154 patients (57 hyperthyroid patients, 61 euthyroid patients, and 36 hypothyroid patients; mean age, 47.9 years) were enrolled. Serum leptin, ghrelin, and insulin levels were measured and insulin resistance was calculated using the formula of the homeostasis model assessment of insulin resistance (HOMA-IR).
  
  
  RESULTS
  There were no differences in mean concentrations of ghrelin or leptin among the three groups. There were no significant differences in insulin levels between the groups (P=0.06), although hyperthyroid patients had borderline statistically significantly higher levels of insulin than did euthyroid subjects by post hoc test (26.4 μIU/mL vs. 16.1 μIU/mL, P=0.057). Regarding HOMA-IR index, the mean levels were highest in the hyperthyroid group among those of the three groups (hyperthyroid vs. euthyroid vs. hypothyroid, 6.7 vs. 3.8 vs. 4.4, P=0.068). Plasma levels of ghrelin were significantly negatively correlated with age, insulin, glucose, body mass index (BMI), and HOMA-IR. Plasma levels of leptin showed significant positive correlation with BMI and triglyceride. There were no significant correlations among thyroid hormone, thyrotropin, ghrelin, leptin, or insulin.
  
  
  CONCLUSIONS
  The present study found that serum ghrelin, leptin, and insulin levels didn't differ according to thyroid function conditions. Further studies with larger numbers of patients are required to establish a direct relationship between plasma ghrelin, leptin, and thyroid hormone.
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Soonchunhyang University Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon, Korea.
authors.forename: Kyu Jin
authors.initials: KJ
authors.lastname: Kim
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Soonchunhyang University Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon, Korea.
authors.forename: Bo Yeon
authors.initials: BY
authors.lastname: Kim
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Soonchunhyang University Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon, Korea.
authors.forename: Ji Oh
authors.initials: JO
authors.lastname: Mok
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Soonchunhyang University Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon, Korea.
authors.forename: Chul Hee
authors.initials: CH
authors.lastname: Kim
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Soonchunhyang University Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon, Korea.
authors.forename: Sung Koo
authors.initials: SK
authors.lastname: Kang
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Soonchunhyang University Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon, Korea. chanh@schmc.ac.kr.
authors.forename: Chan Hee
authors.initials: CH
authors.lastname: Jung
keywords: Ghrelin; Insulin; Insulin resistance; Leptin; Thyroid hormones