Carbamoylcholine and gastrin induce inositol lipid turnover in canine gastric parietal cells.
The potential role of inositol phospholipid turnover in mediating acid secretion was examined in a preparation enriched for isolated canine gastric parietal cells. The stimulatory effects of carbamoylcholine (carbachol) and gastrin on parietal cell uptake of [14C]aminopyrine were linked to dose- and time-dependent selective reduction in cellular phosphatidylinositol content, although the specific fatty acid composition of the phosphoinositides was not altered. Analysis of [3H]inositol phosphates accumulated in cells prelabeled with [3H]inositol revealed an increase in labeled inositol trisphosphate by 5 min of incubation with either carbachol or gastrin. Furthermore, after preincubation of parietal cells in medium containing [32P]orthophosphate, the two secretagogues elicited a time-dependent decrease in 32P labeling of phosphatidylinositol 4,5-bisphosphate and concomitant increase in labeling of phosphatidic acid. These data demonstrate that the acid secretagogue actions of carbachol and gastrin are correlated with turnover of cellular inositol phospholipids in a preparation consisting predominantly of parietal cells.
Chiba
T
T
Department of Internal Medicine, University of Michigan Medical School, Ann Arbor 48109-0362.
Fisher
S K
SK
Park
J
J
Seguin
E B
EB
Agranoff
B W
BW
Yamada
T
T
D000632:Aminopyrine / Q000378:metabolism; D000818:Animals; D002217:Carbachol / Q000494:pharmacology*; D004285:Dogs; D005755:Gastrins / Q000494:pharmacology*; D006632:Histamine / Q000494:pharmacology; D010295:Parietal Cells, Gastric / Q000187:drug effects / Q000378:metabolism*; D010716:Phosphatidylinositols / Q000378:metabolism*; D013997:Time Factors
D005755:Gastrins; D010716:Phosphatidylinositols; D000632:Aminopyrine; D006632:Histamine; D002217:Carbachol