title: Decreased IGF-1 concentration during the first trimester of pregnancy in women with normal somatotroph function.
abstract: BACKGROUND
  A decrease of insulin-like growth factor-I levels (IGF-I) has been reported during the first trimester of pregnancy in women with acromegaly before the secretion of placental growth hormone (GH) progressively increases IGF-1 concentration.
  
  
  METHODS
  To evaluate variations of concentrations of IGF-1, insulin-like growth factor (IGF)-binding protein-3 (IGF-BP3) and GH during the first trimester of pregnancy in women with normal somatotroph function.
  
  
  METHODS
  Sixteen women (median age 31 years) with as who were followed for benign thyroid disorders (n = 15) or prolactin-secreting microadenoma (n = 1) were evaluated before and in the first trimester of pregnancy. Serum concentrations of GH, IGF-1, IGF-BP3, TSH and estradiol (E2) were measured before and in the first trimester (5.4 ± 2.2 weeks of gestation).
  
  
  RESULTS
  Before pregnancy, somatotroph and thyroid functions (median TSH 1.2 mU/L) were normal in all women. At the first trimester IGF-1 levels decreased significantly (before = 210 ng/mL, first trimester = 145 ng/mL, p < 0.001) with no significant change in GH (before = 1.5 ng/mL, first trimester = 0.84 ng/mL) or IGF-BP3 levels (before = 2.3 ng/mL, first trimester = 2.2 ng/mL), while estradiol levels increased significantly (before = 46.5 pg/100 mL, first trimester = 448.5 pg/100 mL, p < 0.001).
  
  
  CONCLUSIONS
  In women with normal somatotroph function, IGF-1 levels decrease in the first trimester of pregnancy without changes in GH or IGF-BP3 levels. These results confirm liver resistance to GH as a consequence of the physiological increase of estrogens during the first trimester.
authors.affiliation: Department of Endocrinology and Metabolic Diseases, Pôle Cardio-Vasculaire et Métabolique, CHU Larrey, 24 Chemin de Pouvourville, TSA 30030, 31059, Toulouse Cedex 9, France.
authors.forename: Marie-Laure
authors.initials: ML
authors.lastname: Persechini
authors.forename: Isabelle
authors.initials: I
authors.lastname: Gennero
authors.forename: Solange
authors.initials: S
authors.lastname: Grunenwald
authors.forename: Delphine
authors.initials: D
authors.lastname: Vezzosi
authors.forename: Antoine
authors.initials: A
authors.lastname: Bennet
authors.forename: Philippe
authors.initials: P
authors.lastname: Caron
mesh_terms: D000328:Adult; D015331:Cohort Studies; D004958:Estradiol / Q000378:metabolism; D005260:Female; D019382:Human Growth Hormone / Q000378:metabolism*; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D011247:Pregnancy / Q000378:metabolism*; D011261:Pregnancy Trimester, First / Q000378:metabolism*; D011446:Prospective Studies; D052683:Somatotrophs; D013972:Thyrotropin / Q000378:metabolism
chemical_list: C515497:IGFBP3 protein, human; D018972:Insulin-Like Growth Factor Binding Protein 3; D019382:Human Growth Hormone; D004958:Estradiol; D007334:Insulin-Like Growth Factor I; D013972:Thyrotropin