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Hypothalamic pituitary adrenal function in the extremely low birth weight infant
C E Hanna1, L D Keith, M A Colasurdo
1Department of Pediatrics, Oregon Health Sciences University, Portland 97201.
The Journal of Clinical Endocrinology and Metabolism
|February 1, 1993
Summary
Extremely premature infants show normal pituitary and adrenal responses to stimulation, despite clinical signs of adrenal insufficiency. This suggests potential issues with stress recognition or hypothalamic CRH secretion in the premature brain.
Area of Science:
- Endocrinology
- Neonatology
- Pediatric Research
Background:
- Extremely premature infants often exhibit symptoms suggestive of adrenal insufficiency.
- However, serum cortisol levels in ill preterm infants do not always reflect expected stress responses.
Purpose of the Study:
- To investigate the hypothalamic-pituitary-adrenal (HPA) axis function in extremely low birth weight (ELBW) stressed premature infants.
- To assess pituitary response to ovine corticotropin-releasing hormone (oCRH) and adrenal response to adrenocorticotropic hormone (ACTH).
Main Methods:
- The study involved 17 ELBW premature infants (mean birth weight 739g, gestational age 26.1 weeks).
- Infants received ovine CRH (oCRH) stimulation followed by ACTH stimulation 24 hours later.
- Plasma ACTH, cortisol, and CRH immunoactivity were measured at various time points.
Main Results:
- Pituitary response to oCRH showed a significant rise in ACTH and cortisol levels.
- Adrenal response to ACTH stimulation also resulted in a significant cortisol increase.
- Plasma CRH immunoactivity was detectable and higher in infants compared to adult controls.
Conclusions:
- The HPA axis demonstrates normal pituitary and adrenal responsiveness in these extremely premature infants.
- Inappropriately low cortisol levels in some ill preterm infants may stem from impaired brain stress recognition or insufficient hypothalamic CRH secretion.
- The clinical significance of measurable plasma CRH in the first week of life requires further investigation.