Hormonal control of ADP-ribosyl cyclase activity in pancreatic acinar cells from rats.
Cyclic ADP-ribose, a metabolite of NAD+ evokes Ca2+ release from intracellular stores in different cells. We have determined the activity of cADPr-producing enzymes (ADP-ribosyl cyclases) in different cellular fractions prepared from isolated pancreatic acinar cells by measuring the conversion of the beta-NAD+ analogs 1,N6-etheno-NAD and nicotinamide guanine dinucleotide to the fluorescent products 1,N6-etheno-cADPr and cyclic GDP-ribose, respectively. Substrate/product analyses were carried out by reverse-phase high pressure liquid chromatography. In all subcellular fractions examined (cytosol, mitochondria, plasma, and intracellular membranes), ADP-ribosyl cyclase activity was detected except in zymogen granular membranes. Western blot analysis and immunoprecipitation experiments revealed the presence of the ADP-ribosyl cyclase CD38 in both plasma membranes and mitochondria but not in the cytosol. Hormonal stimulation of intact acinar cells for 1 min with acetylcholine (ACh), cholecystokinin (CCK), or a membrane-permeant analog of cGMP increased ADP-ribosyl cyclase activity in the cytosol by 1.8-, 1.6-, and 1.9-fold, respectively, as compared with the control but had no effect in any other fraction. Both ACh and CCK also increased accumulation of cGMP in the cells by about 2-fold. Bombesin had no significant effect on either ADP-ribosyl cyclase activity or cGMP accumulation within this short period of stimulation. We conclude that at least two types of ADP-ribosyl cyclases are present in pancreatic acinar cells: membrane-bound CD38 and a cytosolic enzyme different from CD38. Stimulation of pancreatic acinar cells with CCK or ACh results in exclusive activation of the cytosolic ADP-ribosyl cyclase activity, most likely mediated by cGMP.
Sternfeld
Lutz
L
University of the Saarland, Institute of Physiology, Building 58, 66421 Homburg, Germany.
Krause
Elmar
E
Guse
Andreas H
AH
Schulz
Irene
I
D036541:ADP-ribosyl Cyclase / Q000096:biosynthesis / Q000378:metabolism*; D051997:ADP-ribosyl Cyclase 1; D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D015703:Antigens, CD / Q000096:biosynthesis; D015153:Blotting, Western; D001839:Bombesin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002766:Cholecystokinin / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D006152:Cyclic GMP / Q000378:metabolism; D006150:Guanine Nucleotides / Q000737:chemistry; D006728:Hormones / Q000378:metabolism*; D008297:Male; D008562:Membrane Glycoproteins; D008928:Mitochondria / Q000378:metabolism; D009243:NAD / Q000031:analogs & derivatives* / Q000737:chemistry; D010179:Pancreas / Q000166:cytology / Q000201:enzymology*; D011233:Precipitin Tests; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013347:Subcellular Fractions / Q000378:metabolism
D015703:Antigens, CD; D006150:Guanine Nucleotides; D006728:Hormones; D008562:Membrane Glycoproteins; D009243:NAD; C011038:nicotinamide 1,N(6)-ethenoadenine dinucleotide; C102728:nicotinamide guanine dinucleotide; D002766:Cholecystokinin; D036541:ADP-ribosyl Cyclase; C498156:Cd38 protein, rat; D051997:ADP-ribosyl Cyclase 1; D000254:Sodium-Potassium-Exchanging ATPase; D006152:Cyclic GMP; D000109:Acetylcholine; D001839:Bombesin; D002118:Calcium