Urinary prostacyclin and thromboxane A2 metabolites in preterm and full-term infants in relation to plasma renin activity and blood pressure.

The metabolites of prostacyclin and thromboxane A2, 6-ketoprostaglandin F1 alpha 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 F1 alpha excretion was significantly higher in the preterm infants as compared to the full-term infants (p less than 0.001). This decrease of 6-ketoprostaglandin F1 alpha 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.