Abstract
The present study was undertaken to examine the effects of anoxia and/or low pH on active organic ion transport and tissue water and electrolyte distribution in freshly prepared cortical slices from harbor seal and rat kidneys.p-Aminohippurate (PAH) and tetraethylammonium (TEA) were used as a representative organic anion and cation, respectively. The slice uptake of PAH was not influenced by the incubation medium pH over a range of 5.0–7.5 in the harbor seal while it was very sensitive to the medium pH in the rat, decreasing significantly with reductions in pH (Fig. 1). Although the TEA uptake decreased in anoxia in both species, it decreased considerably less in the harbor seal than in the rat (40% vs 74%) (Fig. 2). However, in contrast to the PAH transport system, the TEA uptake decreased significantly at low pH in both species. The magnitudes of increase in intracellular Na and of decrease in intracellular K in anoxia were consistently less in the harbor seal than in the rat, especially at low pH (Fig. 3). However, the pH dependence of Na−K-ATPase activity of the crude renal cortical homogenate was not different between the two species (Fig. 4). These results, together with the previous finding on the anoxic tolerance of the renal organic anion transport system, indicate that (1) the overall anoxic tolerance of active renal transport systems for both organic anions and cations is greater in the harbor seal than in the rat, and (2) the renal organic anion (but not cation) transport system is resistant to low pH in the harbor seal.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call