| Autor: |
Maxild, J, Møller, J V, Iqbal Sheikh, M |
| Zdroj: |
Journal of Physiology; June 1981, Vol. 315 Issue: 1 p189-201, 13p |
| Abstrakt: |
1. The relation between renal accumulation of p‐aminohippurate (PAH), Na+‐K+‐ATPase activity, and the transmembranal Na+ gradient has been investigated by the use of cortex slices of rabbit kidney. 2. A moderate stimulation of PAH uptake rate was observed under anaerobic conditions in the presence of an extracellular‐to‐intracellular directed gradient of Na+. 3. Inhibition of aerobic accumulation of PAH by ouabain was related to a decrease in Na+‐K+‐ATPase activity, as evidenced by changes in tissue concentrations of Na+ and K+ and by measurements of high‐affinity binding of ouabain to the slices. 4. Accumulation of PAH in media with various concentrations of Na+ and K+ resembled the effect of the cations on the ATPase activity of an isolated preparation of Na+‐K+‐ATPase. 5. Counteraction of the inhibitory effect of ouabain on PAH accumulation by a high concentration of K+ in the medium was related to retention of Na+‐K+‐ATPase activity, as evidenced by preservation of tissue‐‐medium gradients of Na+ and K+. 6. The present data provide strong evidence for the involvement of Na+‐K+‐ATPase in the energization of renal PAH accumulation. However, it appears probable that a metabolic (Na+‐gradient‐independent) component, in addition to a Na+ gradient, is essential for the attainment of high accumulation ratios of PAH by intact renal cells. |
| Databáze: |
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