text: The influence of extra-umbilical serotonin, PGE2 and PGF2 alpha on prostanoid production in human umbilical arteries.
  The influence of extra-umbilical applications of serotonin and prostaglandins PGE2 and PGF2 alpha on the endogenous production of prostacyclin and thromboxane in human umbilical arteries was registered during in vitro perfusion by use of specific radio-immunoassays. PGE2 and PGF2 alpha caused significant dose-dependent increases in the production of prostacyclin, but no specific alterations in that of thromboxane. Serotonin did not lead to any changes in the prostanoid formation. The results provide indirect support for the assumption that prostanoids synthesized in the vessel wall, predominantly in the endothelial cells, serve as mediators in the action of autacoids on vascular smooth muscle tension.