Urinary Prostacyclin and Thromboxane A2Metabolites in Preterm and Full-Term Infants in Relation to Plasma Renin Activity and Blood Pressure

The metabolites of prostacyclin and thromboxane A₂, 6-ketoprostaglandin F_1α and thromboxane B₂, were measured in urine of 27 preterm and 21 full-term infants. Their values were analyzed in correlation to plasma renin activity, urinary function, and systolic blood pressure. The 6-ketoprostaglandin F_1α excretion was significantly higher in the preterm infants as compared to the full-term infants (p < 0.001). This decrease of 6-ketoprostaglandin F_1α in the full-term infants was associated with a decrease in the plasma renin activity and an increase in systolic blood pressure. In contrast, the urinary excretion of thromboxane B₂ was low, without significant difference between the two groups, and there was no correlation to the parameters mentioned above.