Differential prostacyclin production by human umbilical vasculature.

Using the avidin-biotin immunohistochemical technique with rabbit antihuman 6-keto-prostaglandin (PG)-F1 alpha (6KPGF), we studied the distribution of the stable prostacyclin metabolite, 6KPGF, in 14 formaldehyde-fixed human umbilical cords. All umbilical veins demonstrated intense endothelial cell staining. None of the arteries stained. To corroborate the immunohistochemical findings, three fresh umbilical cords were dissected to separate arteries from veins and then were incubated in oxygenated tissue baths containing Ringer's lactate (37 degrees C) for 30 minutes. Cumulative 6KPGF production as measured by radioimmunoassay of tissue effluents was markedly different between arteries and veins with the umbilical vein producing the largest quantity of 6KPGF. Thus, immunohistochemistry and ex vivo capacitance studies suggest that there is a differential distribution of 6KPGF in human umbilical arteries and veins.