The contribution of inositol exchange to agonist-stimulated breakdown of myo- [2-3H] inositol-labelled phosphatidylinositol in mouse exocrine pancreas.
Agonists stimulate the release of myo-inositol from phosphatidylinositol (PtdIns) labelled in vivo with myo-[2-3H] inositol. In the presence of lithium, which inhibits myo-inositol-1-phosphatase, the compound which accumulates following the breakdown of pre-labelled PtdIns is inositol-1-phosphate. This indicates that the agonist-stimulated release of the head group from this lipid is not the result of inositol exchange and is due to phosphodiesterase activity. The total amount of 3H-labelled compounds released from PtdIns in the presence and absence of lithium is the same, which indicates the labelled compounds which are released are not re-incorporated. Agonist-induced release of myo-[2-3H] inositol can be used as a reliable indication of PtdIns breakdown in the exocrine pancreas.
D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D066298:In Vitro Techniques; D007294:Inositol / Q000378:metabolism*; D008094:Lithium / Q000494:pharmacology; D051379:Mice; D010179:Pancreas / Q000187:drug effects / Q000378:metabolism*; D010716:Phosphatidylinositols / Q000378:metabolism*
D010716:Phosphatidylinositols; D007294:Inositol; D002217:Carbachol; D008094:Lithium