Dissociation of vascular resistance with endocrine pancreas secretion: The effects of epoxymethano analogs of PGH2

The epoxymethano analogs of PGH₂ caused rapid and persistent increase in perfusion pressure in isolated rat pancreata without significant effect on glucagon and insulin secretory responses to PGH₂ and PGE₂. The changes in perfusion pressure are interpreted as alterations in vascular resistance since the flow rate was kept constant at 2.5 mL per min. PGH₂ alone caused significant elevation in pressure. However, PGH2 administration superimposed upon an infused epoxymethano analog of PGH₂, decreased perfusion pressure significantly, whereas PGH₂ induced hormone release was not decreased. The analogs neither stimulated nor inhibited the endocrine pancreas secretion. These studies provide evidence for complete dissociation of vascular constriction from pancreatic hormone release and further suggest that the effects of PGH₂ on islet hormone secretion may result from the conversion of PGH₂ to other prostanoids.