Abstract
The uptakes of 3H-ouabain and 3H-digitoxin (5 x 10-8 M) by rabbit myometrium and (10-6 M) by rat myometrium reached equilibrium after one hour. The uptake of 3H-ouabain by rabbit myometrium was antagonized by K+ and was Na+ and adenosine triphosphate-dependent. It was also reduced by low temperatures, unlabeled ouabain and digitoxin and by high concentrations of Cs+. The uptake of 3H-ouabain by rat myometrium did not show any of these characteristics. The uptake of 3H-digitoxin by rabbit and rat myometrium was similar and was found to be unaltered by changes in K+ or Na+ concentrations in the media. 3H-digitoxin uptake was also not significantly reduced by depletion of ATP or by unlabeled digitoxin or ouabain. Thus uptake of ouabain by rabbit myometrium appeared to be related to transport ATPase. No evidence for dependence of uptake of digitoxin on this enzyme was found. In the case of rat myometrium no evidence was found that uptake of ouabain was related to transport adenosine triphosphatase.
Footnotes
- Received September 17, 1971.
- Accepted February 29, 1972.
- © 1972, by The Williams & Wilkins Company
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