The formation of free and lipid myo-inositol in the intact rat

Abstract

1. 1. The incorporation of 14C into the free and lipid-bound myo-inositol of rat brain, liver, kidney and blood was measured after the injection of [ 14C 6]glucose and other radioactive substances into young and adult rats. 2. 2. In brain, radioactivity appeared in free inositol and in lipid-inositol bound in phosphatides and phosphatidopeptides after the injection of [ 14C 6]glucose. Highest specific activity was observed in free blood inositol. The time curves of incorporation are consistent with the involvement of free inositol in the assembly of inositol phosphatide in brain; however, the inositol-containing lipids in phosphatidopeptides appear to belong to a different pool. 3. 3. Both free and phosphatide inositol of liver and kidney also became labeled, with higher activity occurring in the free inositol. Specific activities in young rats were about twice as great as in adult ones. Sodium [2- 14C]pyruvate gave rise to labeled inositol (both free and bound) in brain, liver and kidney, but no incorporation was obtained with sodium [1- 14C]acetate or sodium [6- 14C]glucuronate. 4. 4. In addition to these findings data on the amounts of inositol isolated and on the incorporation of 14C of glucose and pyruvate into phosphatide glycerol are presented.