Ouabain-insensitive transintestinal transport in the rat jejunum incubated in vitro.
The jejunal tract of rat intestine, everted and incubated in vitro at 28 degrees C for 2 hr in Krebs-Ringer bicarbonate solution, was used to test the existence of a ouabain-insensitive sodium pump. Cell water, Na, and K together with Na, fluid, K, and lactate transported into the serosal compartment were determined and, under control conditions, the tested parameters were found constant in time. By blocking the Na-K pump with 20 mM ouabain in the serosal compartment, the enterocyte lost K and gained Na, but the cell volume did not vary. Moreover, the transport of Na, fluid, and lactate, although lower, was constant for 2 hr. When ethacrynate was added or when the ATP supply was blocked by adding 2,4-dinitrophenol plus iodoacetate, the cell swelled and the transport of Na and fluid stopped. These results are interpreted as suggesting the existence of a ouabain-insensitive Na pump, in addition to the well-known Na-K pump.
D019297:2,4-Dinitrophenol; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D004140:Dinitrophenols / Q000494:pharmacology; D004976:Ethacrynic Acid / Q000494:pharmacology; D066298:In Vitro Techniques; D007461:Iodoacetates / Q000494:pharmacology; D019807:Iodoacetic Acid; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism; D007583:Jejunum / Q000378:metabolism*; D007773:Lactates / Q000378:metabolism; D019344:Lactic Acid; D010042:Ouabain / Q000494:pharmacology*; D011188:Potassium / Q000378:metabolism; D051381:Rats; D012964:Sodium / Q000378:metabolism
D004140:Dinitrophenols; D007461:Iodoacetates; D007473:Ion Channels; D007773:Lactates; D019344:Lactic Acid; D010042:Ouabain; D012964:Sodium; D004976:Ethacrynic Acid; D019297:2,4-Dinitrophenol; D011188:Potassium; D019807:Iodoacetic Acid