14CO2 production and 14C incorporation into proteins was studied in isolated rat sciatic nerves during incubation with 0.1 mM [1-14C]leucine. Rats were made diabetic with streptozotocin. Nerves from diabetic rats incubated with glucose oxidized more [14C]leucine than controls. This difference was abolished in the presence of insulin (1 mU/ml). The effects of diabetes and insulin on leucine oxidation could not be demonstrated in the absence of glucose. Insulin stimulated the incorporation of [14C] from leucine into proteins by nerves from controls and diabetic rats. Nerves undergoing Wallerian degeneration showed a marked increase in DNA content and stimulated incorporation of leucine into proteins. 14CO2 production from leucine proceeded at 75% of the rate observed in intact nerves. Neither insulin nor diabetes affected leucine metabolism in degenerating nerves. Neither the extracellular space nor the concentration of free amino acids were significantly different in nerves obtained from control and diabetic rats, except for lower glutamine content in the latter. In vitro leucine metabolism of nerves is affected by diabetes, insulin and the integrity of the axon. The Schwann cell is suggested as a possible site of the observed changes in leucine metabolism.
|Original language||English (US)|
|Number of pages||7|
|Journal||Journal of Neurochemistry|
|State||Published - 1976|
ASJC Scopus subject areas
- Cellular and Molecular Neuroscience