Compensatory changes in calcium uptake and phospholipid composition in rat renal brush border membranes after unilateral nephrectomy.

Unilateral nephrectomy (uNX) induces a decrease in calcium uptake by brush border membranes (BBM) in the remnant kidney compared to control membranes. This effect was found to occur within 48 h and persisted at 2 weeks after uNX. Moreover, this decreased calcium uptake appears to occur through a diminished binding capacity of the BBM. Our studies also show that renal hypertrophy induced a specific decrease in the content of acidic phospholipids in remnant kidney BBM by 48 h after uNX. The decrease in phosphatidylinositol 4,5-bisphosphate and phosphatidic acid was transitory but phosphatidylinositol 4-monophosphate levels remained lower in the BBM at 2 weeks after uNX compared to control membranes. These results suggest that the decreased calcium uptake by remnant kidney BBM after uNX is related to a decreased membrane content of acidic phospholipids. This effect might account, at least in part, for the decrease in fractional calcium reabsorption during renal compensatory hypertrophy.