Evidence for de novo synthesis of phosphatidylinositol coupled with histamine release in activated rat mast cells.
Phospholipid metabolisms in rat mast cells activated by ionophore A23187 and compound 48/80 were examined with reference to 'phosphatidylinositol (PI) cycle'. The addition of A23187 to [3H]glycerol-prelabeled mast cells induced a marked accumulation of the radioactivity in 1,2-diacylglycerol(DG) and phosphatidic acid(PA) within 10 to 30 sec. A great enhancement of [3H]glycerol incorporation into PA and PI was also detected during histamine release. On the other hand, 48/80 was far less effective than A23187 both in producing 1,2- DG and PA and in accerelating [3H]glycerol incorporation into PA and PI, despite the comparable ability of histamine release. The activity of Ca2+ uptake into mast cells, as measured by pulse-labeling with 45Ca2+, was increased when exposed to both of two agents. These data provide circumstantial evidence that phospholipid metabolisms, mainly de novo PI synthesis, may be a part of the triggering events for Ca2+ mobilization and secretory process. The PI metabolism induced by two different stimulants appears to behave in a different manner.
D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D005990:Glycerol / Q000378:metabolism; D006632:Histamine / Q000378:metabolism*; D008407:Mast Cells / Q000187:drug effects / Q000378:metabolism*; D010716:Phosphatidylinositols / Q000096:biosynthesis*; D051381:Rats; D011919:Rats, Inbred Strains; D003189:p-Methoxy-N-methylphenethylamine / Q000494:pharmacology
D010716:Phosphatidylinositols; D000001:Calcimycin; D003189:p-Methoxy-N-methylphenethylamine; D006632:Histamine; D005990:Glycerol