Cardiorespiratory depression and plasma beta-endorphin levels in low-birth-weight infants during the first day of life
S. Davidson, I. Gil-Ad, H. Rogovin, Z. Laron and S. H. Reisner
Twenty-nine premature infants were studied to determine whether neonatal
asphyxia, apnea, and low blood pressure in the first day of life are
associated with elevated plasma beta-endorphin concentrations. Plasma
beta-endorphin levels were determined at 0.5 to 2, 4 to 6, and 18 to 24
hours of life, using radioimmunoassay. Premature infants with moderate or
severe asphyxia (n = 19) had higher levels at 0.5 to 2 hours of age (32.1
+/- 6.7 vs 16.4 +/- 7.4 pmol/L) and significantly higher levels at 4 to 6
hours of age (50.4 +/- 10.0 vs 22.9 +/- 9.2 pmol/L) compared with the ten
nonasphyxiated premature infants. A significant elevation in levels at age
0.5 to 2 hours (39.4 +/- 9.9 vs 17.7 +/- 4.4 pmol/L) and age 4 to 6 hours
(59.3 +/- 13.8 vs 27.1 +/- 17.1 pmol/L) was observed in premature infants
with low blood pressure or impaired perfusion (n = 12) who required the
administration of volume expanders. No differences were observed in
premature infants with and without apnea. It may be speculated that the
increased endogenous release of beta-endorphins in response to perinatal
asphyxia may play a role in the pathogenesis of shock observed in the first
day of life.