AJP - Renal Physiology, Vol 249, Issue 1 117-F123, Copyright © 1985 by American Physiological Society
Effect of 1,25-dihydroxyvitamin D3 on phospholipid composition of rat renal brush border membrane
M. Tsutsumi, U. Alvarez, L. V. Avioli and K. A. Hruska
To analyze the effects of vitamin D on renal tubular cell membrane
phospholipid metabolism, the effects of vitamin D depletion and repletion
on renal brush border membrane (BBM) phosphatidylethanolamine (PE),
phosphatidylcholine (PC), and phosphatidylinositol (PI) were studied. The
PC content of BBM from kidneys of rats deprived of vitamin D for 5-6 wk was
33.5 +/- 2.2 nmol Pi/mg protein. This was significantly lower than the PC
content of BBM from kidneys of rats supplemented with vitamin D2 for 2 wk,
41.0 +/- 0.4 nmol Pi/mg protein. Vitamin D depletion also decreased the
content of BBM PE. The fatty acid composition of BBM PC was altered by
vitamin D depletion. Vitamin D depletion increased palmitic acid and
decreased stearic, linoleic, and arachidonic acid. Vitamin D repletion with
a single physiological dose of 1,25(OH)2D3 (30 pmol), 16 h prior to study
tended to increase membrane content of PC and significantly increased the
linoleic acid content of the PC fraction. Single-dose vitamin D repletion
with a pharmacological dose of 1,25(OH)2D3 (2.4 nmol) produced a
significant increase in BBM content of PC and also significantly increased
the linoleic acid content of PC. These results demonstrate that vitamin D
deficiency affects PC and PE content of rat renal BBM and their fatty acid
composition, and that vitamin D repletion with 1,25(OH)2D3 for 16 h
partially normalizes the changes in PC.
