Dissociation of intestinal active sugar transport from (Na ++K +) ATPase activity

1. 1. The possible relationship of small intestinal sodium and potassium-stimulated adenosine triphosphatase activity [(Na + + K +) ATPase] to sugar transport was studied in rats in vitro. 2. 2. Because arbutin ( P-hydroxyphenyl- β-glucoside) is actively transported by the small intestine of the rat in the same manner as glucose and is not metabolized, it was used in these studies. 3. 3. Incubations were commenced in a medium containing 3 mM arbutin and 1 mM sodium deoxycholate for 25 min, then, after washing, continued under identical conditions and in a similar medium without added bile salt. 4. 4. The inhibitory effect thereby demonstrated on intestinal active sugar transport was acutely reversible while the inhibitory effect on (Na + + K +)ATPase activity was not. 5. 5. Under the experimental conditions described, normal (Na + + K +)ATPase activity is not essential for intestinal active sugar transport to occur. 6. 6. The technique used is a convenient means to study further the relationship of (Na + + K +)ATPase to intestinal transport and is applicable to human tissue specimens.