Effect of extracellular acidosis on 45Ca uptake in isolated hypoxic proximal tubules.

Abstract

Recent in vitro studies have suggested that the presence of extracellular acidosis is protective against the development of oxygen-deprivation injury in several tissues. Because cellular Ca accumulation after renal ischemia may represent a major pathogenic event leading to cellular damage, the purpose of the present study was to examine the effect of extracellular acidosis on 45Ca uptake and desaturation in normal and hypoxic isolated rat proximal tubules. At pH 7.4, an increase in 45Ca uptake was observed in proximal tubules after 30 min of hypoxia. In addition, 45Ca desaturation was increased significantly in hypoxic tubules at pH 7.4. The alterations in 45Ca uptake and desaturation in hypoxic tubules at pH 7.4 were accompanied by significant signs of cellular injury as assessed by the amount of lactate dehydrogenase (LDH) released by the tubules at the end of the hypoxic period (22.5% above control tubules, P less than 0.01) as well as in morphological changes consistent with hypoxic cell injury. In contrast, when maintained at pH 6.9 throughout the study, no difference in 45Ca uptake or desaturation was observed between the control and hypoxic tubules; the hypoxic proximal tubules exhibited a smaller increase in LDH release (12.7% above control tubules) and did not develop the morphological changes observed at pH 7.4. Thus, during hypoxia and reoxygenation at pH 7.4, the increased 45Ca uptake may contribute in part to cellular injury in rat proximal tubules.

• Authors: M Burnier, V J Van Putten, A Schieppati, R W Schrier
• Journal: The American journal of physiology (Am J Physiol) Vol. 254 Issue 6 Pt 1 Pg. C839-46 (Jun 1988) ISSN: 0002-9513 [Print] United States
• PMID: 3377071 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S., Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Adenosine Triphosphate
• L-Lactate Dehydrogenase
• Oxygen
• Calcium

Topics

• Acid-Base Equilibrium
• Adenosine Triphosphate (metabolism)
• Animals
• Calcium (metabolism)
• Hydrogen-Ion Concentration
• Kidney Tubules, Proximal (enzymology, metabolism, ultrastructure)
• L-Lactate Dehydrogenase (metabolism)
• Male
• Microscopy, Electron
• Organ Culture Techniques
• Oxygen (physiology)
• Rats
• Rats, Inbred Strains