Identification and metabolism of polyphosphoinositides in isolated islets of Langerhans

Abstract

Isolated islets were incubated with [32P]P1 and radiolabelling of polyphosphoinositides were determined. Labelling equilibrium was approached after 45 min, with a half-time of 15 min. D-Glucose decreased the amount of [32P]PO4 in phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] and phosphatidylinositol 4-phosphate (PtdIns4P) within 0.5 min, and loss of radiolabel was still evident at 1 min. [32P]PO4 levels in polyphosphoinositides returned to basal levels within 5 min. Neither D-galactose nor D-glucose af…