Parveen R, Grahn M F, Butterworth P J
Biochim Biophys Acta. 1986 Apr 25;856(3):624-8. doi: 10.1016/0005-2736(86)90156-2.
Previous work from this laboratory has shown that isolated chick renal proximal tubule cells possess an Na+-dependent Pi transport system and that Pi uptake is stimulated under gluconeogenic conditions. It is shown in the present paper that gluconeogenesis is associated with a rapid incorporation of Pi into membrane phospholipids, particularly phosphatidylinositol, and some evidence has been obtained for a change in the relative amounts of phosphatidylinositol polyphosphates under gluconeogenic conditions. There is no increase in the total phospholipid phosphate content however, suggesting that pyruvate-induced incorporation of Pi into phospholipids represents accelerated turnover rather than a net increase in synthesis. It is suggested that the stimulation of Na+-dependent Pi uptake by pyruvate is related to the increased rate of phospholipid turnover. Thus Pi transport may be a further example of a physiological system that is influenced by phosphatidylinositol metabolism. The role of phosphatidylinositol phosphates could be to stimulate transfer of transporter molecules from internal stores to the brush-border membrane of the cell.
