| Autor: |
Sugihira, Naoko, Aoki, Yasunobu, Suzuki, Kazuo |
| Zdroj: |
Biological Trace Element Research; Jul1992, Vol. 34 Issue 1, p45-54, 10p |
| Abstrakt: |
ATP-dependent Sr transport was examined in vitro using basolateral membrane (BLM) vesicles isolated from rat renal cortex to clarify the discrimination mechanisms between strontium (Sr) and calcium (Ca) in renal tubules during reabsorption. ATP-dependent Sr uptake and Ca uptake were observed in renal BLM vesicles and were inhibited by vanadate. Hill plots indicate similar kinetic behavior for Ca and Sr uptake. The apparent K and V of ATP-dependent Sr uptake were both higher than those for Ca uptake. ATP-dependent Sr uptake by BLM vesicles diminished in the presence of 0.1 μ M Ca and was more markedly inhibited by 1 μM Ca. Hill plots of Sr uptake data with and without 0.1 μ M Ca showed that the cooperative behavior of Sr uptake was not changed by Ca. In the presence of 0.1 μ M Ca, the affinity of the transport system for Sr and the velocity of Sr uptake in the BLM were both decreased. However, the rate of Ca uptake was not diminished by Sr concentrations of <1.6 μ M. These results suggest that Ca is preferentially transported in the renal cortex BLM when Ca and Sr are present at the same time. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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