Plasma prostacyclin from birth to adolescence.

The plasma concentration of 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha), the stable hydration product of prostacyclin, was measured by radioimmunoassay in 111 healthy children aged between 1 day and 16 years and in 21 healthy adults aged between 21 and 72 years. The 6-keto-PGF1 alpha levels in children up to age 16 years were higher than those in adults. During the first 4 days of life the plasma concentrations of 6-keto-PGF1 alpha in term infants were higher (P less than 0.05) than the respective levels in preterm infants. There was no difference between the 6-keto-PGF1 alpha levels measured simultaneously in umbilical arterial and peripheral venous plasma in 7 newborn infants. Maternal pre-eclampsia or epidural analgesia during labour, mode of delivery, birthweight, or sex of the infants were not related to the plasma 6-keto-PGF1 alpha levels on the first day of life. High levels of vasodilatory and anti-aggregatory prostacyclin during the first days of life may play a role in the postnatal adaptation of the circulation and platelet function.