title: The pituitary-adrenal responses to exogenous human corticotropin-releasing hormone in preterm, very low birth weight infants.
abstract: To evaluate the pituitary-adrenal reserve and to standardize the methodology of performing the human CRH (hCRH) stimulation test, we performed the hCRH test on 14 preterm (< 32 gestational weeks), very low birth weight infants, who did not receive antenatal or postnatal corticosteroid treatment, on days 7 and 14 of life. Blood samples were obtained 0 (baseline), 15, 30, and 60 min after an iv dose of hCRH (1 microgram/kg). The plasma ACTH concentration rose from a basal value of 5.7 +/- 0.6 pmol/L (mean +/- SEM) to 11.9 +/- 2.1 pmol/L (P < 0.005), 9.2 +/- 1.2 pmol/L (P < 0.005), and 7.7 +/- 0.8 pmol/L (P < 0.005) at 15, 30, and 60 min, respectively. The corresponding rises in serum cortisol from a basal concentration of 396 +/- 67 nmol/L were 509 +/- 71 nmol/L (P < 0.0001), 647 +/- 62 nmol/L (P < 0.0001), and 578 +/- 60 nmol/L (P < 0.0001). The plasma ACTH concentration consistently peaked early at 15 min, whereas the maximum cortisol response occurred 30 min post-hCRH stimulation. No significant differences were detected between the hCRH tests performed on days 7 and 14 (P > 0.15). Mechanical ventilation, infant gender, and mode of delivery did not significantly influence the hormonal responses (P > 0.25). We have defined in this study the pattern, the magnitude of the pituitary-adrenal response, and the timing of the peak concentrations of plasma ACTH and serum cortisol in relation to a standard iv dose of hCRH. The hCRH test in very low birth weight infants appears to be safe and reproducible, and produces a pituitary-adrenal response comparable to that seen in older children and adults, indicating that pituitary-adrenal function is mature at these early stages of gestation.
authors.affiliation: Department of Pediatrics, Prince of Wales Hospital, Chinese University of Hong Kong.
authors.forename: P C
authors.initials: PC
authors.lastname: Ng
authors.forename: G W
authors.initials: GW
authors.lastname: Wong
authors.forename: C W
authors.initials: CW
authors.lastname: Lam
authors.forename: C H
authors.initials: CH
authors.lastname: Lee
authors.forename: M Y
authors.initials: MY
authors.lastname: Wong
authors.forename: T F
authors.initials: TF
authors.lastname: Fok
authors.forename: W
authors.initials: W
authors.lastname: Wong
authors.forename: D C
authors.initials: DC
authors.lastname: Chan
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000097:blood; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007234:Infant, Premature; D007275:Injections, Intravenous; D008297:Male; D009994:Osmolar Concentration; D010913:Pituitary-Adrenal System / Q000187:drug effects*; D013997:Time Factors
chemical_list: D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D006854:Hydrocortisone