Regeneration of the renal brush border after renal ischemia in rats

Abstract

An early change following mild renal ischemia is the loss of the renal microvilli, which then regenerate morphologically within 6 h. We studied microvillar regeneration in rats with 25 min of renal artery occlusion and subsequent reflow. At subsequent intervals the rats were injected intraperitoneally with [14C]choline and [3H]leucine; 25 min later they were killed and their renal brush border membranes isolated. At 30 min of reflow of blood there was a 77% reduction in the incorporation of [3H]leucine into microvillar protein compared with that of the opposite control kidney (P less than 0.02). The incorporation rose to normal within 60 min. At 30 min of reflow, the incorporation of [14C]choline into phospholipids increased twofold (P less than 0.005), then returned toward normal values after 2 h. The altered incorporation of tracers was not due to change in membrane turnover or substrate pools. The activities of alkaline phosphatase, gamma-glutamyl transpeptidase, and alpha-glucosidase decreased 50% following ischemia (P less than 0.02) and returned to control values within 2 h. Thus, renal damage severe enough to partly efface microvilli is repaired metabolically within several hours.

Changes in antigen expression on human fme melanoma cells after exposure to hypoxia and acidic ph, alone or in combination

“…Other factors that might be of importance for the reduced antigen expression are hypoxia-induced changes in the protein metabolism. Hypoxia reduces protein synthesis (Paddock et al, 1981;Shrieve et al, 1983;Heacock and Sutherland, 1986;Pettersen et al, 1986), and increases protein degradation (Pettersen et al, 1986). Another possibility is that antigenic determinants may either have been damaged or have undergone conformational changes.…”

Catalytic Activities of Alkaline Phosphatase and N-Acetyl-ß-D-Glucosaminidase in Human Cortical Nephron Segments: Heterogeneous Changes in Acute Renal Failure and Acute Rejection Following Kidney Allotransplantation

“…However, the outcome of the transplantation does not seem to depend on intact brush-border membranes, äs suggested from alkaline phosphatase activities in proximal tubules of intraoperative biopsies A t , B t , and Dj. Favoured by good metabolic conditions, brush-border membranes can be rapidly restored (28,29), äs indicated by normal alkaline phosphatase activities in biopsies D 2 (14), the proximal straight tubules also showed a decreased Nacetyl-ß-J9-glücosaminidase activity. This may indicate that tubular cells are more severely affected by preceding warm and cold ischaemia.…”

Exercise-Induced Urinary Abnormalities in Long-Distance Runners

“…Indeed, precise identification of these cell types, which could be either leukocytes or tubular cells, is not often possible (5). However, the significant increase in yGT and NAG activity in the post-race urine samples indicate an important tubular impairment during strenuous exercise, The increase in urinary excretion of both NAG, which has a high tubular lysosome activity, and 'yGT, located on the renal brush border, might point to tubular cell ischemic injury, as hypothesized in experimental animals (13,19) and in hypertensive men (10,11). The post-race increase in plasma renin activity and in plasma aldosterone --and the modification of electrolyte excretion --could help to explain the renal hemodynamic modifications during exercise.…”