Rapid changes in hepatocyte phosphoinositides induced by vasopressin.
Vasopressin stimulated a 40% decrease in [32P]phosphatidylinositol 4,5-bisphosphate and a 15% decrease in [32P]phosphatidylinositol within 30 s of addition to hepatocytes prelabeled for 60 min with 32P. In hepatocytes prelabeled with [3H]inositol for 60 min, vasopressin produced 20% breakdown of phosphatidylinositol and 33% breakdown of phosphatidylinositol 4,5-bisphosphate within 30 s. There was a 40% increase in total phosphatidylinositol 4,5-bisphosphate within 30 s of vasopressin addition. Breakdown of phosphatidylinositol accounted for disappearance of 95% of the inositol lipid label. In hepatocytes from rats labeled in vivo with [3H]inositol, vasopressin stimulated 10% loss of labeled phosphatidylinositol. Loss of [32P]phosphatidylinositol due to vasopressin was followed by reincorporation of label to levels greater than control while 32P reuptake into phosphatidylinositol 4,5-bisphosphate did not exceed control values. With in vitro [3H]inositol-labeled hepatocytes, loss of label from the phosphoinositides was followed by reuptake of tritium label to control levels. In hepatocytes labeled in vivo with [3H]inositol, reuptake of [3H]inositol label did not occur. These data indicate that the hormone-sensitive pool of hepatocyte phosphoinositides can be labeled by both in vitro and in vivo procedures. Vasopressin induces a rapid decrease of labeled phosphatidylinositol and phosphatidylinositol 4,5-bisphosphate within 30 s.
D000818:Animals; D005260:Female; D066298:In Vitro Techniques; D007294:Inositol / Q000378:metabolism; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism; D010716:Phosphatidylinositols / Q000302:isolation & purification / Q000378:metabolism*; D010743:Phospholipids / Q000096:biosynthesis / Q000302:isolation & purification; D010761:Phosphorus Radioisotopes; D051381:Rats; D014316:Tritium; D014667:Vasopressins / Q000494:pharmacology*
D010710:Phosphates; D010716:Phosphatidylinositols; D010743:Phospholipids; D010761:Phosphorus Radioisotopes; D014316:Tritium; D014667:Vasopressins; D007294:Inositol