Evidence for a single pool of myo-inositol in hormone-responsive WRK-1 cells.

Previous reports have suggested the existence of at least two pools of cellular myo-inositol (Ins); it has been further hypothesized that only one of these pools is utilized during hormone-activated, cyclic phosphatidylinositol (PtdIns) resynthesis. In an effort to investigate this possibility, we have undertaken kinetic studies of Ins metabolism in WRK-1 cells. Our results indicate that a single pool of Ins is involved in both basal and activated PtdIns synthesis. Ins generated by the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PtdInsP2) mixes with the existing pool of free Ins and is not used exclusively for resynthesis of PtdIns.