Potassium transport across basolateral membrane of acinar cells in the perfused rat pancreas.
Efflux and influx of K+ across the basolateral membrane of acinar cells were continuously computed from the change in K+ concentration in the perfusate collected from the portal vein of the isolated perfused rat pancreas. Continuous stimulation with different concentrations of COOH-terminal octapeptide of cholecystokinin (CCK-8) caused characteristic patterns of K+ flux and fluid secretion as follows: 1) stimulation with 10 pM CCK-8 induced a gradual and small increase in K+ influx and sustained fluid secretion; 2) stimulation with 100 pM CCK-8 caused an initial transient K+ efflux followed by a secondary slow K+ influx and sustained fluid secretion; 3) stimulation with 1 nM CCK-8 also induced an initial transient K+ efflux followed by a secondary slow K+ influx, whereas there was only a slight transient increase in fluid secretion. Ouabain abolished the CCK-8-induced K+ influx, but furosemide had little, if any, effect on the CCK-8-induced K+ flux and fluid secretion. Complete replacement of Cl- with equimolar NO3- had little effect on the CCK-8-induced K+ influx. These results suggest that CCK-8 activates not only passive K+ transport but also an ouabain sensitive Na(+)-K+ pump and that the furosemide-sensitive Na(+)-K(+)-2Cl- symport may not play a significant role in CCK-8-induced K+ transport.
Department of Physiology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan.
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Ishikawa
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Kanno
D000818:Animals; D001692:Biological Transport; D002712:Chlorides / Q000494:pharmacology; D005665:Furosemide / Q000494:pharmacology; D008094:Lithium / Q000494:pharmacology; D008297:Male; D010042:Ouabain / Q000494:pharmacology; D010179:Pancreas / Q000166:cytology / Q000378:metabolism*; D010477:Perfusion; D011188:Potassium / Q000493:pharmacokinetics*; D051381:Rats; D011919:Rats, Inbred Strains; D012146:Rest; D012844:Sincalide / Q000494:pharmacology; D012964:Sodium / Q000494:pharmacology; D019789:Tetraethylammonium; D013757:Tetraethylammonium Compounds / Q000494:pharmacology
D002712:Chlorides; D013757:Tetraethylammonium Compounds; D010042:Ouabain; D019789:Tetraethylammonium; D005665:Furosemide; D008094:Lithium; D012964:Sodium; D012844:Sincalide; D011188:Potassium