Calcium and monoamine regulation: role of vitamin D nutrition.

The mechanism of vitamin D participation in the processes of monoamine regulation was studied. Central and peripheral endogenous norepinephrine levels were compared in vitamin D deficient rats, in preventative vitamin D3 (1 IU/day) administered rats, and in lactose (20% of the diet) administered rats, lactose being known to increase intestinal absorption of calcium. Vitamin D deficiency resulted in a significant decrease in endogenous norepinephrine. The decrease was of variable magnitude according to the considered organs. The adrenal dopamine level was also less in vitamin D deficient rats than in rats given vitamin D in preventive treatment. However, it remained in the brain. In the absence of vitamin D dietary lactose restored blood calcium and endogenous norepinephrine levels in all the tissues, except in the liver. It appears that the decrease in norepinephrine storage in vitamin D deficient rats resulted from a lack of calcium rather than from the absence of vitamin D.