Na+ dependence of in vitro pancreatic amylase release.
The effects of Na+ on the in vitro release of amylase from mouse pancreas were studied. Replacement of Na+ in the medium by Tris, choline, or sucrose blocked the stimulation of amylase release by bethanechol and caerulein, whereas replacement by Li+ was without effect. The inhibiton was rapid and reversible, with stimulated amylase release linearly related to the log of the medium Na+ concentration over the range of 20-100 mM Na+. In contrast to the inhibition of amylase release stimulated by physiological secretagogues, enzyme release stimulated by the Ca2+ ionophore A23187 was unaffected by removal of Na+ from the medium. Tissue and intracellular Na+ and K+ contents were unchanged after stimulation of secretion by physiological stimulants. It is concluded that Na+ may be important in the early steps of stimulus-secretion coupling leading to the putative rise in intracellular Ca2+ that triggers pancreatic enzyme release.
D000681:Amylases / Q000378:metabolism*; D000818:Animals; D001626:Bethanechol Compounds / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002794:Choline / Q000494:pharmacology; D008297:Male; D051379:Mice; D010179:Pancreas / Q000187:drug effects / Q000201:enzymology*; D012964:Sodium / Q000494:pharmacology*; D013268:Stimulation, Chemical; D013395:Sucrose / Q000494:pharmacology; D014325:Tromethamine / Q000494:pharmacology
D001626:Bethanechol Compounds; D014325:Tromethamine; D000001:Calcimycin; D013395:Sucrose; D012964:Sodium; D000681:Amylases; D002794:Choline; D002118:Calcium