Effect of vitamin D deficiency on lipid composition and calcium transport in basolateral membrane vesicles from chick intestine.

Vitamin D deficiency affects the lipid composition and Ca2+ uptake of intestinal basolateral membranes from chick intestine. The increased cholesterol content causes an increase in the molar ratio cholesterol/phospholipid. Phospholipid classes remain unchanged, but the percentages of arachidonic acid from the from the major phospholipid fractions are increased. After 24 hours of oral administration of 2,000 IU of cholecalciferol to vitamin D-deficient chicks, the cholesterol values do not change, but the amount of arachidonic acid returns to normal values. Ca2+ uptake driven by ATP is diminished in vesicles from intestinal basolateral membranes of vitamin D-deficient chicks. Cholecalciferol treatment returns these values to the controls which might be due mainly to the increased number of Ca2+ pump units. In conclusion, changes in lipid composition and in Ca2+ pump caused by vitamin D deficiency seems to play a role in the decrease of vesicular Ca2+ transport. A single dose of cholecalciferol restores only partially the lipid-protein changes produced by vitamin D deficiency.

Phospholipids and sialic acid changes produced by vitamin D3 on intestinal mitochondria.

Vitamin D3 administration to vitamin D-deficient chicks produces, 24 hours after treatment, a large increment of phospholipids in mitochondria from intestinal mucosa. Proportion of the different phospholipid classes and fatty acid composition of the organelles were not modified by that treatment. A time course study of the effects of 1,25(OH)2D3 on calcium absorption and sialic acid content of intestinal mitochondria glycoproteins showed that both effects were correlated. The results suggest that either vitamin D or the increase of calcium transfer are involved in the make up of intestinal mitochondria membranes.