title: Glucocorticoid exposure of sheep at 0.7 to 0.75 gestation augments late-gestation fetal stress responses.
abstract: OBJECTIVE
  Exposure to glucocorticoid levels inappropriately high for current maturation alters fetal hypothalamo-pituitary-adrenal axis (HPAA) development. In an established fetal sheep model, we determined whether clinical betamethasone doses used to accelerate fetal lung maturation have persistent effects on fetal HPAA hypotensive-stress responses.
  
  
  METHODS
  Pregnant ewes received saline (n = 6) or betamethasone (n = 6); 2 × 110 μg/kg body weight doses injected 24 hours apart (106/107 and 112/113 days' gestational age, term 150 days). Basal adrenocorticotropin (ACTH) and cortisol and responses to fetal hypotension were measured before and 5 days after the first course and 14 days after the second course.
  
  
  RESULTS
  Basal ACTH and cortisol were similar with treatment. HPAA responses to hypotension increased after the second but not first course and ACTH/cortisol ratio increased indicating central HPAA effects.
  
  
  CONCLUSIONS
  Results demonstrate latency in the emergence of fetal HPAA hyperresponsiveness following betamethasone exposure that may explain hyperresponsiveness in full-term but not preterm neonates.
authors.affiliation: Department of Neurology, Friedrich Schiller University, Jena, Germany. Matthias.Schwab@med.uni-jena.de
authors.forename: Matthias
authors.initials: M
authors.lastname: Schwab
authors.forename: Turhan
authors.initials: T
authors.lastname: Coksaygan
authors.forename: Florian
authors.initials: F
authors.lastname: Rakers
authors.forename: Peter W
authors.initials: PW
authors.lastname: Nathanielsz
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000097:blood; D000818:Animals; D001623:Betamethasone / Q000009:adverse effects / Q000494:pharmacology*; D005260:Female; D005333:Fetus / Q000187:drug effects; D005938:Glucocorticoids / Q000009:adverse effects / Q000494:pharmacology*; D006854:Hydrocortisone / Q000097:blood; D007022:Hypotension / Q000097:blood / Q000139:chemically induced*; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects; D010913:Pituitary-Adrenal System / Q000187:drug effects; D011247:Pregnancy; D012756:Sheep; D013312:Stress, Physiological / Q000187:drug effects*
chemical_list: D005938:Glucocorticoids; D000324:Adrenocorticotropic Hormone; D001623:Betamethasone; D006854:Hydrocortisone