The effect of cycloheximide on the activity of lactate dehydrogenase in transected peripheral nerves of the dog and of the rat

Abstract

1. 1. The changes in LDH activity were studied after transection of the peripheral nerves of the dog and of the rat. 2. 2. The cutting of the nerve evokes an increase in LDH activity near the lesion; the increment is higher in the nerves of the dog than in those of the rat. 3. 3. The increase in LDH activity in transected nerves is a local phenomenon limited to a few millimeters both sides of the lesion. The degree of the increment is similar to that of another soluble enzyme—phosphoglucoisomerase (PGI) and much smaller than that of membrane-bound AChE. 4. 4. The intraperitoneal injection of cycloheximide diminishes the increase in LDH activity found after transection of the nerve. In rat nerves the inhibition of the increment was total, while in dog nerves it was only partial. 5. 5. It may be supposed that the increment of LDH activity in transected nerves is mainly connected with synthesis of this enzyme as a reaction to injury. It is not to be excluded, however, that an activation of LDH also occurs. 6. 6. Cycloheximide, in doses of 45 and 70 mg/kg body wt., does not affect the axonal transport as examined by changes in AChE activity in transected nerves.