plasma pg concentrations were determined by radioimmunoassay for two vasodilators , pge2 and pgi2 ( as measured by its metabolite 6-keto-pgf1 alpha ) , and two vasoconstrictors , thromboxane ( tx ) a2 and pgf2 alpha , as measured by their metabolites txb2 and pgf2 alpha-m , respectively .
C0033554
pg
C0012472
pge2