Effect of high K+ exposure on phosphoinositide metabolism in frog skeletal muscle.
Using [3H]myo-inositol labeled frog skeletal muscles, we have studied the effect of high K+ exposure on phosphoinositide metabolism. After 12 hours labeling, 80mM K+ exposure induced a time-dependent change. The labeling associated with phosphatidylinositol (PI) and phosphatidylinositol 4-phosphate (PIP) gradually increased and decreased, respectively. The labeled phosphatidylinositol 4,5-bisphosphate (PIP2) first decreased, and then recovered. An accumulation of the labeling in inositol phosphates was shown. In shortening the labeling to 30 min, 15 min high K+ exposure was found to only increase the labeling in all fractions. Taken together, these results show that high K+ exposure can activate the turnover of phosphoinositides, which is consistent with the hypothesis that the metabolism of phosphoinositides may regulate excitation- contraction (e-c) coupling.
Dong
Z
Z
Shanghai Institute of Physiology, Chinese Academy of Sciences.
Chen
K Y
KY
Zhu
P H
PH
D000818:Animals; D066298:In Vitro Techniques; D007294:Inositol / Q000378:metabolism; D007700:Kinetics; D009132:Muscles / Q000187:drug effects / Q000378:metabolism*; D010716:Phosphatidylinositols / Q000302:isolation & purification / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology*; D011898:Ranidae; D014316:Tritium
D010716:Phosphatidylinositols; D014316:Tritium; D007294:Inositol; D011188:Potassium