Dynamic changes in cytosolic and mitochondrial ATP levels in pancreatic acinar cells.
OBJECTIVE
Previous studies of pancreatic acinar cells characterized the effects of Ca(2+)-releasing secretagogues and substances, inducing acute pancreatitis on mitochondrial Ca(2+), transmembrane potential, and NAD(P)H, but dynamic measurements of the crucial intracellular adenosine triphosphate (ATP) levels have not been reported. Here we characterized the effects of these agents on ATP levels in the cytosol and mitochondria.


METHODS
ATP levels were monitored using cytosolic- or mitochondrial-targeted luciferases.


RESULTS
Inhibition of oxidative phosphorylation produced a substantial decrease in cytosolic ATP comparable to that induced by inhibition of glycolysis. Cholecystokinin-8 (CCK) increased cytosolic ATP in spite of accelerating ATP consumption. Acetylcholine, caerulein, and bombesin had similar effect. A bile acid, taurolithocholic acid 3-sulfate (TLC-S); a fatty acid, palmitoleic acid (POA); and palmitoleic acid ethyl ester (POAEE) reduced cytosolic ATP. The ATP decrease in response to these substances was observed in cells with intact or inhibited oxidative phosphorylation. TLC-S, POA, and POAEE reduced mitochondrial ATP, whereas physiological CCK increased mitochondrial ATP. Supramaximal CCK produced a biphasic response composed of a small initial decline followed by a stronger increase.


CONCLUSIONS
Both glycolysis and oxidative phosphorylation make substantial contributions to ATP production in acinar cells. Ca(2+)-releasing secretagogues increased ATP level in the cytosol and mitochondria of intact isolated cells. TLC-S, POA, and POAEE reduced cytosolic and mitochondrial ATP. When cells rely on nonoxidative ATP production, secretagogues as well as TLC-S, POA, and POAEE all diminish cytosolic ATP levels.
Voronina
Svetlana G
SG
The Physiological Laboratory, School of Biomedical Sciences, The University of Liverpool, Liverpool, United Kingdom.
Barrow
Stephanie L
SL
Simpson
Alec W M
AW
Gerasimenko
Oleg V
OV
da Silva Xavier
Gabriela
G
Rutter
Guy A
GA
Petersen
Ole H
OH
Tepikin
Alexei V
AV
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D000963:Antimetabolites / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D002766:Cholecystokinin / Q000378:metabolism; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005229:Fatty Acids, Monounsaturated / Q000378:metabolism; D006019:Glycolysis / Q000187:drug effects; D007476:Ionophores / Q000494:pharmacology; D007700:Kinetics; D008156:Luciferases / Q000096:biosynthesis / Q000235:genetics; D008297:Male; D051379:Mice; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D010085:Oxidative Phosphorylation; D046790:Pancreas, Exocrine / Q000187:drug effects / Q000378:metabolism*; D013658:Taurolithocholic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D014162:Transfection
D000963:Antimetabolites; D004791:Enzyme Inhibitors; D005229:Fatty Acids, Monounsaturated; D007476:Ionophores; C066776:taurolithocholic acid 3-sulfate; C008757:palmitoleic acid; D013658:Taurolithocholic Acid; D000255:Adenosine Triphosphate; D002766:Cholecystokinin; D008156:Luciferases; D002118:Calcium