A study of stabilization of gluconeogenic activity in rat liver slices by calcium and manganese ions.

1. The effect of some bivalent cations on gluconeogenesis by the rat liver-slice preparation has been investigated. 2. Ca(2+) and Mn(2+) stimulated glucose production from a range of substrates but not from glycerol. Mg(2+) had no effect on the rate of glucose production. 3. Ca(2+) were required to maintain phosphoenolpyruvate carboxylase activity in the slice preparation. 4. Ca(2+) and Mn(2+), but not Mg(2+), retarded the release of lysosomal enzymes from the slice into the incubation medium. 5. It is proposed that Ca(2+) and Mn(2+) stimulate glucose production by stabilizing the lysosome system in the liver-slice preparation. 6. The value of the liver-slice preparation as a means of measuring hepatic gluconeogenesis is discussed.