Diurnal rhythms of cortisol, ACTH, and beta-endorphin levels in neonates and adults

• Published in: The Western journal of medicine Vol. 151; no. 2; pp. 153 - 156
• Main Authors: Hindmarsh, K W, Tan, L, Sankaran, K, Laxdal, V A
• Format: Journal Article
• Language: English
• Published: United States BMJ Publishing Group Ltd 01.08.1989; BMJ Publishing Group LTD
• Subjects: ACTH; Adrenocorticotropic Hormone - blood; Adult; Beta-endorphin; beta-Endorphin - blood; Circadian Rhythm; Circadian rhythms; Endorphins; Environmental aspects; Evaluation; Humans; Hydrocortisone - blood; Infant, Newborn; Infants (Newborn); Intensive care units; Intensive Care Units, Neonatal; Measurement; Physiological aspects; Stress, Psychological - blood
• ISSN: 0093-0415; 1476-2978

To determine whether a diurnal rhythm exists in neonates admitted to neonatal intensive care units where there is continuous artificial lighting and periodic nursing and medical care, plasma cortisol, adrenocorticotropin (ACTH), and beta-endorphin concentrations were measured in two groups of infants and in adult human volunteers. As expected, a diurnal rhythm was seen in adults. A diurnal rhythm was also found for cortisol and endorphin levels in neonates (3 to 4 days postnatally) with minimal stress and in infants who were clinically severely stressed. There was not a significant difference between the morning and afternoon concentrations of ACTH in these infants, but the afternoon concentrations were lower than the morning's, as would be expected. We found that a diurnal rhythm does exist in neonates within the first few days of postnatal life and that the continuous lighting and medical and nursing interventions do not interfere with this rhythm.