Rapid changes in hepatocyte phosphoinositides induced by vasopressin

• Published in: The Journal of biological chemistry 1983-11, Vol.258 (22), p.13727-13732
• Main Authors: Litosch, I, Lin, S H, Fain, J N
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Cell physiology; Female; Fundamental and applied biological sciences. Psychology; Hormonal regulation; In Vitro Techniques; Inositol - metabolism; Kinetics; Liver - drug effects; Liver - metabolism; Molecular and cellular biology; Phosphates - metabolism; Phosphatidylinositols - isolation & purification; Phosphatidylinositols - metabolism; Phospholipids - biosynthesis; Phospholipids - isolation & purification; Phosphorus Radioisotopes; Rats; Tritium; Vasopressins - pharmacology
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(17)43978-0

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.