| Abstract: | In a particulate preparation from rat brain, manganese ions stimulate the incorporation of 3H]inositol into inositol phospholipids in a concentration-dependent manner. Incubation with CDP-diacylglycerol (0.5 mM) alone had no effect on the incorporation of 3H]inositol but potentiated the stimulatory effect of manganese. Despite the increase in 3H]inositol incorporation into phosphatidylinositol, the carbachol-induced accumulation of 3H]inositol-1-phosphate was unaltered in membranes preincubated with manganese but when coincubated with CDP-diacylglycerol the carbachol-induced accumulation of 3H]inositol-1-phosphate was increased. These data suggest that manganese stimulates the incorporation of 3H]inositol into an agonist-insensitive pool of phosphatidylinositol. |
