title: Levothyroxine treatment restored the decreased circulating fibroblast growth factor 21 levels in patients with hypothyroidism.
abstract: OBJECTIVE
  Fibroblast growth factor 21 (FGF21) is an important endogenous regulator of energy metabolism. Thyroid hormone has been shown to regulate hepatic FGF21 expression in rodents. The goal of this study was to evaluate the plasma FGF21 levels in participants with normal thyroid function, subclinical hypothyroidism, or overt hypothyroidism and to investigate the change of plasma FGF21 levels in patients with overt hypothyroidism after levothyroxine treatment.
  
  
  METHODS
  A total of 473 drug-naive participants were recruited, including 250 healthy control subjects, 116 patients with subclinical hypothyroidism, and 107 patients with overt hypothyroidism. Thirty-eight patients with overt hypothyroidism were assigned to receive levothyroxine treatment.
  
  
  RESULTS
  The overt hypothyroidism group had decreased FGF21 levels compared with the control and subclinical hypothyroidism groups (P<0.01). Levothyroxine treatment markedly attenuated the increased circulating levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), high-sensitivity C-reactive protein (hsCRP), and homeostasis model assessment index of insulin resistance (HOMA-IR) in patients with overt hypothyroidism. A significant increase in plasma FGF21 levels was observed after levothyroxine treatment (P<0.01). The change in FGF21 levels was correlated with the increase of FT3 and FT4 after levothyroxine treatment (FT3: r=0.44; FT4: r=0.53; all P<0.05).
  
  
  CONCLUSIONS
  Levothyroxine treatment ameliorated metabolic disorders and restored the decreased circulating FGF21 levels in patients with overt hypothyroidism. The increase in FGF21 levels after levothyroxine treatment might be partly associated with the amelioration of metabolic disorders in patients with hypothyroidism.
authors.affiliation: Department of Endocrinology, Beijing Chao-yang Hospital, Capital Medical University, No. 8, Gongti South Road, Chaoyang district, Beijing 100020, China. Electronic address: drwg6688@126.com.
authors.forename: Guang
authors.initials: G
authors.lastname: Wang
authors.affiliation: Department of Endocrinology, Beijing Chao-yang Hospital, Capital Medical University, No. 8, Gongti South Road, Chaoyang district, Beijing 100020, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Endocrinology, Beijing Chao-yang Hospital, Capital Medical University, No. 8, Gongti South Road, Chaoyang district, Beijing 100020, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Yang
authors.affiliation: Department of Endocrinology, Beijing Chao-yang Hospital, Capital Medical University, No. 8, Gongti South Road, Chaoyang district, Beijing 100020, China.
authors.forename: Yanjin
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Department of Endocrinology, Beijing Chao-yang Hospital, Capital Medical University, No. 8, Gongti South Road, Chaoyang district, Beijing 100020, China.
authors.forename: Heng
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Endocrinology, Beijing Chao-yang Hospital, Capital Medical University, No. 8, Gongti South Road, Chaoyang district, Beijing 100020, China.
authors.forename: Li
authors.initials: L
authors.lastname: Miao
authors.affiliation: Department of Endocrinology, Beijing Chao-yang Hospital, Capital Medical University, No. 8, Gongti South Road, Chaoyang district, Beijing 100020, China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Yao
authors.affiliation: Department of Endocrinology, Beijing Chao-yang Hospital, Capital Medical University, No. 8, Gongti South Road, Chaoyang district, Beijing 100020, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Xu
mesh_terms: D000328:Adult; D002097:C-Reactive Protein / Q000032:analysis; D016022:Case-Control Studies; D002681:China; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D005260:Female; D005346:Fibroblast Growth Factors / Q000097:blood*; D006801:Humans; D007037:Hypothyroidism / Q000097:blood* / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012044:Regression Analysis; D013963:Thyroid Hormones / Q000097:blood*; D013974:Thyroxine / Q000627:therapeutic use*
chemical_list: D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D013963:Thyroid Hormones; C414620:fibroblast growth factor 21; D005346:Fibroblast Growth Factors; D002097:C-Reactive Protein; D013974:Thyroxine
keywords: Fibroblast growth factor 21; Hypothyroidism; Metabolism