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Pituitary-adrenal response to bacterial endotoxin in developing rats
1Department of Physiology, Loyola University of Chicago, Maywood, Illinois 60153.
The American Journal of Physiology
|October 1, 1988
Summary
Neonatal rats show a temporary loss of corticosterone response to endotoxin between 5-14 days old, despite elevated ACTH. This indicates a reduced adrenal cortex sensitivity to ACTH during this critical developmental window.
Area of Science:
- Endocrinology
- Neonatal Physiology
- Immunology
Background:
- Neonatal rats are highly susceptible to lethal endotoxin effects.
- Pituitary-adrenal secretions are crucial for stress adaptation.
Purpose of the Study:
- To investigate the developmental changes in plasma corticosterone and adrenocorticotropic hormone (ACTH) responses to endotoxin in neonatal rats.
Main Methods:
- Assessed lethal endotoxin sensitivity across different ages (1-21 days).
- Measured plasma corticosterone and ACTH levels after endotoxin administration.
- Evaluated corticosterone response to exogenous ACTH in developing rats.
Main Results:
- Neonatal rats (1-2 days) and adult rats showed significant corticosterone elevation post-endotoxin.
- Rats aged 5-14 days exhibited depressed corticosterone increments despite elevated ACTH.
- Adrenal cortex responsiveness to ACTH was diminished in hyporesponsive age groups.
Conclusions:
- The newborn rat's ability to respond to endotoxin with corticosterone secretion is transiently lost between 5-14 days.
- This loss of response is attributed to decreased adrenal cortex sensitivity to ACTH, not insufficient ACTH production.