The present study was undertaken to establish the developmental pattern of urinary endothelin-1 (ET-1) excretion and to define its possible role in mediating pathophysiological changes related to perinatal asphyxia/infection and dopamine treatment. Urinary ET-1 levels were measured by radioimmunoassay in 7 full-term neonates (mean gestational age 39.3 weeks) on days 1, 3 and 5, and in 9 pre-term neonates (mean gestational age 30.8 weeks) on days 1, 3, 5, 7 and weekly thereafter for 5 consecutive, weeks. The results were compared with those of three age-groups of 30 normal children (4-8 years, 9-12 years and 13-18 years); each group, consisted of 10 children. The influence of severe cardiopulmonary distress (n=16, mean gestational age 33.9 weeks, post-natal age 3.3 days) and dopamine administration in a dose of 2 μg/min per kg (n=10, mean gestational and post-natal ages 32.1 weeks and 5.6 days, respectively) were also studied. In full-term infants, ET-1 concentration fell from 34.3±1.8 pmol/l on day 1 to 21.5±1.5 pmol/l on day 5 (P<0.01). In premature infants its absolute value and its post-natal fall were similar in the 1st week and no further change occurred in weeks 2-5; it stabilized at levels between 17.1±2.2 and 16.7±1.7 pmol/l. These concentrations tended to be lower than those of 25.5±1.3, 23.0±1.0 and 26.2±0.7 pmol/l measured in three groups of older children. During the 1st week, daily ET-1 excretion remained unchanged in term infants (3.1±1.0 vs. 3.7±1.5 pmol/m2 per day), but there was a significant increase from 6.5±1.0 to 12.4±0.7 pmol/m2 per day (P<0.01) in premature infants. During weeks 2-5, preterm infants excreted more ET-1 than older children (P<0.01). In response to perinatal ashphyxia/infection and dopamine therapy, urinary ET-1 excretion markedly rose and there was a significant positive correlation between urine flow rate and ET-1 excretion (P<0.001). We conclude that ET-1 concentration rather than excretion rate may have a role in mediating the changes in renal functions that occur soon after birth. The pathophysiological significance of the flow-dependent increase in urinary ET-1 excretion needs to be further studied.
ASJC Scopus subject areas
- Pediatrics, Perinatology, and Child Health