Interconversion of inositol (1,4,5)-trisphosphate to inositol (1,3,4,5)-tetrakisphosphate and (1,3,4)-trisphosphate in permeabilized adrenal glomerulosa cells is calcium-sensitive and ATP-dependent.
The metabolism of [3H]inositol (1,4,5)-trisphosphate was followed in permeabilized bovine adrenal glomerulosa cells. At low Ca++ concentration (pCa = 7.2), more than 90% of [3H]inositol (1,4,5)-trisphosphate had disappeared within 2 min, while two other metabolites, [3H]inositol (1,3,4)-trisphosphate and [3H]inositol (1,3,4,5)-tetrakisphosphate appeared progressively. At higher Ca++ concentrations (pCa = 5.7 and 4.8), the formation of these two metabolites was markedly increased, but completely abolished if the medium was ATP-depleted. The peak levels for the generation of [3H]inositol (1,3,4,5)-tetrakisphosphate (1 min) preceded those of [3H]inositol (1,3,4)-trisphosphate and were closely correlated. These results suggest that, in adrenal glomerulosa cells, the isomer inositol (1,3,4)-trisphosphate is generated from inositol (1,4,5)-trisphosphate via a calcium-sensitive and ATP-dependent phosphorylation/dephosphorylation pathway involving the formation of inositol (1,3,4,5)-tetrakisphosphate.
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000311:Adrenal Glands / Q000166:cytology / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002417:Cattle; D002478:Cells, Cultured; D015544:Inositol 1,4,5-Trisphosphate; D007295:Inositol Phosphates / Q000378:metabolism*; D010766:Phosphorylation; D013403:Sugar Phosphates / Q000378:metabolism*; D014316:Tritium
D007295:Inositol Phosphates; D013403:Sugar Phosphates; D014316:Tritium; C081655:inositol-1,3,4,5-tetrakisphosphate; D015544:Inositol 1,4,5-Trisphosphate; D000255:Adenosine Triphosphate; D002118:Calcium