ABSTRACT
Urinary endothelin-1-like immunoreactivity (ET-1-LI) excretion was determined in 31
neonates, six sick infants with renal dysfunction secondary to neonatal asphyxia and
25 healthy infants, during the first week of life to clarify its evolutional change
and the origin of the urinary ET-1-LI in the newborn period. Urinary ET-1-LI concentrations
in the healthy infants maintained the same level during the first week of life (n = 35, 36 ± 22 pg/mg creatinine, mean ± SD). There was no difference in urinary ET-1-LI
excretion in infants between 30 and 41 weeks of gestation. Urinary ET-1-LI concentrations
in the sick infants were significantly elevated through the first week of life when
compared with those of healthy infants. Fractional excretion of sodium and endothelin
clearance were more elevated in the sick infants than in the healthy infants. A good
correlation was observed between urinary ET-1-LI concentrations and urinary N-acetyl-β-D-glucos-aminidase
index (r = 0.72, p <0.01). These results suggest that the origin of urinary endothelin-1 may be the
renal tissue and that ET-1 may be a nonspecific marker of renal injury in neonates.