Prostaglandin E2 and alpha 2 adrenoceptor agonists inhibit the pentose phosphate shunt in pancreatic islets.

Glucose utilization in isolated pancreatic islets of the rat was inhibited by prostaglandin (PG) E2 and the alpha 2 adrenoceptor agonist, clonidine, to a similar extent; other prostaglandins did not affect glucose utilization. Islet oxidation of [1-14C]glucose and [6-14C]glucose demonstrated that the pentose phosphate shunt was inhibited by PGE2 and clonidine. Pertussis toxin antagonizes the effects of clonidine and PGE2 on total glucose utilization and pentose phosphate shunt activity. The results suggest that PGE2 and alpha 2 adrenoceptor agonists may regulate glucose metabolism through similar transduction mechanisms, and that a guanine nucleotide binding regulatory (G) protein modulates certain metabolic effects of prostaglandins and adrenergic agonists.