Gluconeogenesis in mouse-liver slices

Abstract

1. The rate of gluconeogenesis from amino acids and other known precursors in slices of mouse liver after depletion of liver glycogen by means of phlorrhizin was high with l-lactate, pyruvate, glycerol, d-glyceraldehyde, dihydroxyacetone, d-fructose, sorbitol, xylitol, alpha-glycerophosphate, alanine, proline, threonine, serine and propionate. 2. The rate was unexpectedly low or even negligible with glutamate, aspartate, other glucogenic amino acids and the intermediates of the tricarboxylic acid cycle. 3. Glutamine and asparagine gave higher rates than the corresponding amino acids but still much lower rates than kidney cortex. 4. Livers of male mice gave much lower rates than livers of female mice. Kidney cortex showed no sex difference. 5. Livers of mice fed on a low-carbohydrate diet gave the same rates as livers of mice fed on a normal diet under the test conditions, i.e. 3hr. after an injection of phlorrhizin. 6. Much carbohydrate was formed from endogenous precursors and this was accompanied by release of ammonia and urea. 7. Gluconeogenesis in well-fed mice not treated with phlorrhizin was low. 8. Maximum rates were observed 3hr. after phlorrhizin treatment. 9. Prolonged phlorrhizin treatment did not prevent extensive deposition of liver glycogen, after an initial depletion. 10. Gluconeogenesis in livers of mice fed on a high-fat diet was relatively low. 11. Livers of alloxan-diabetic mice had a high carbohydrate content after phlorrhizin treatment, and gluconeogenesis from endogenous sources was about twice as high as in normal animals. Added substrates had about the same effect in normal and diabetic livers.