title: Limited response to CRH stimulation tests at 2 weeks of age in preterm infants born at less than 30 weeks of gestational age.
abstract: BACKGROUND
  The high incidence of glucocorticoid-responsive complications in extremely preterm infants suggests the immaturity of their adrenal function; however, knowledge of the hypothalamus-pituitary-adrenal (HPA) axis in extremely preterm infants is limited.
  
  
  METHODS
  To clarify the characteristics of the HPA axis in preterm very low birthweight (VLBW) infants, we performed CRH tests repeatedly: at about 2 weeks of age and at term (37-41 weeks of postmenstrual age) for 21 VLBW infants with a gestational age (GA) <30 weeks at birth.
  
  
  RESULTS
  Basal cortisol values at 2 weeks of age were significantly higher than those at term in VLBW infants < 30 weeks of gestation at birth (304·1 ± 146·3 nmol/l vs 184·7 ± 108·2 nmol/l). Response to corticotropin-releasing hormone (CRH) stimulation tests at 2 weeks of age was significantly lower than at term (delta cortisol 148·3 ± 90·7 nmol/l vs 271·8 ± 167·0 nmol/l, delta ACTH 3·9 ± 3·2 pmol/l vs 12·3 ± 9·2 pmol/l, respectively). We found that earlier GA contributed to the higher basal cortisol values, and antenatal glucocorticoid (AG) contributed to the lower response of cortisol to CRH tests at 2 weeks of age.
  
  
  CONCLUSIONS
  VLBW infants showed a characteristic pattern in the HPA axis at 2 weeks of age: higher basal cortisol values and lower response to CRH tests. This study suggested that AG was related to the lower response to CRH tests, at least partly.
authors.affiliation: Department of Pediatrics, Graduate School of Medicine, Kyoto University, Kyoto, Japan. fusako13@kuhp.kyoto-u.ac.jp
authors.forename: Fusako
authors.initials: F
authors.lastname: Niwa
authors.forename: Masahiko
authors.initials: M
authors.lastname: Kawai
authors.forename: Hoshinori
authors.initials: H
authors.lastname: Kanazawa
authors.forename: Kougorou
authors.initials: K
authors.lastname: Iwanaga
authors.forename: Takashi
authors.initials: T
authors.lastname: Matsukura
authors.forename: Minoru
authors.initials: M
authors.lastname: Shibata
authors.forename: Takeshi
authors.initials: T
authors.lastname: Hasegawa
authors.forename: Toshio
authors.initials: T
authors.lastname: Heike
mesh_terms: D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D005260:Female; D005865:Gestational Age; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects / Q000378:metabolism; D007231:Infant, Newborn; D007234:Infant, Premature; D019102:Infant, Very Low Birth Weight; D008297:Male; D010913:Pituitary-Adrenal System / Q000187:drug effects / Q000378:metabolism
chemical_list: D003346:Corticotropin-Releasing Hormone; D006854:Hydrocortisone