Respiratory, ionic, and functional effects of succinate esters in pancreatic islets

New, powerful insulin secretagogues are seen in the form of the methyl esters of succinic acid. The incubation of rat islets takes place regardless of the occurrence of D-glucose, and reveals the rise in O2 uptake due to the secretagogues. The islets reveal biosynthetic activity induced by the secretagogues, with a favoured influence on the preparation of proinsulin. Extracellular Ca2+ is missing in the prelabeling of perifused islets which yield 45Ca efflux hindered by the secretagogues. The total uptake of 45Ca is increased and the outflow of 45Ca in islets which are incubated or perifused when extracellular Ca2+ occurs is biphasically induced.