title: Diurnal rhythm of beta-endorphin in neonates.
abstract: In an attempt to prove whether beta-endorphin diurnal rhythm existed in neonates, 17 infants with a mean (+/- SD) gestational age of 31.7 +/- 4.8 weeks and a birth weight of 1,790 +/- 898 g were studied at a mean postnatal age of 3.3 +/- 0.5 days. Plasma samples were obtained from a pre-existing umbilical arterial line at 09.00 h, noon and 15.00 h. Mean plasma concentrations of beta-endorphin were 68.3 +/- 27.7, 54.5 +/- 13.7, and 45.1 +/- 10.8 pg/ml, respectively. Highly significant (p = 0.0002) variation of plasma beta-endorphin concentration was observed in these neonates suggesting the presence of a diurnal rhythm of beta-endorphin in neonates. It is important to specify the time of collection of blood samples for determination of opiates in neonates.
authors.affiliation: Department of Pediatrics, University of Saskatchewan, Saskatoon, Canada.
authors.forename: K
authors.initials: K
authors.lastname: Sankaran
authors.forename: W
authors.initials: W
authors.lastname: Hindmarsh
authors.forename: L
authors.initials: L
authors.lastname: Tan
mesh_terms: D001238:Asphyxia Neonatorum / Q000097:blood; D002543:Cerebral Hemorrhage / Q000097:blood; D002940:Circadian Rhythm; D006801:Humans; D006819:Hyaline Membrane Disease / Q000097:blood; D007231:Infant, Newborn / Q000097:blood*; D011863:Radioimmunoassay; D001615:beta-Endorphin / Q000097:blood*
chemical_list: D001615:beta-Endorphin