Pharmacologically active levels of PGE1 in neonates with congenital heart disease.

In general, prostanoids act as local mediators, not as circulating hormones. A specific exception to this rule is the infusion of prostaglandin E1 in patients with ductus arteriosus-dependent pulmonary or systemic blood flow associated with congenital heart disease. We therefore measured prostaglandin E1 plasma levels by gas chromatography-mass spectrometry during effective infusion of prostaglandin E1 in 10 neonates. Prostaglandin E1 plasma levels ranged from 22 to 530 (median 56) pg/ml in these patients. Since prostaglandin E1 is not synthesized endogenously to any significant extent, these plasma concentrations constitute genuine circulating levels not confounded by the common problem of e vivo artifacts. If endogenous prostanoids (e.g. prostaglandin E2) are suspected as circulating mediators, plasma levels detected by reliable methods ought to be in the same range as prostaglandin E1 plasma levels in the present investigation.