Secretagogue-induced formation of inositol phosphates in rat exocrine pancreas. Implications for a messenger role for inositol trisphosphate.
The formation of inositol phosphates in response to secretagogues was studied in rat pancreatic acini preincubated with [3H]inositol. Carbachol caused rapid increases in radioactive inositol phosphate, inositol bisphosphate and inositol trisphosphate . This effect was blocked by atropine, and also elicited by caerulein, but not by ionomycin or phorbol dibutyrate. Thus phospholipase C-mediated breakdown of polyphosphoinositides, with the resulting formation of inositol phosphates, may be an early step in the stimulus-secretion coupling pathway in exocrine pancreas. Inositol trisphosphate may function as a second messenger in the exocrine pancreas, coupling receptor activation to internal Ca2+ release.
D000818:Animals; D002217:Carbachol / Q000494:pharmacology*; D002108:Ceruletide / Q000494:pharmacology; D004987:Ethers / Q000494:pharmacology; D066298:In Vitro Techniques; D015544:Inositol 1,4,5-Trisphosphate; D007295:Inositol Phosphates / Q000378:metabolism*; D015759:Ionomycin; D010179:Pancreas / Q000187:drug effects / Q000378:metabolism*; D015240:Phorbol 12,13-Dibutyrate; D010703:Phorbol Esters / Q000494:pharmacology; D051381:Rats; D013403:Sugar Phosphates / Q000378:metabolism*
D004987:Ethers; D007295:Inositol Phosphates; D010703:Phorbol Esters; D013403:Sugar Phosphates; D015240:Phorbol 12,13-Dibutyrate; D015759:Ionomycin; D015544:Inositol 1,4,5-Trisphosphate; D002108:Ceruletide; D002217:Carbachol