Impaired induction of ornithine decarboxylase activity following nerve crush in the streptozotocin-diabetic rat.

ABSTRACT

Ornithine decarboxylase activity was measured in the dorsal root ganglia from crushed and uncrushed contralateral sciatic nerve of control and streptozotocin-diabetic rats. A further group of diabetic rats was treated with insulin throughout the experiment. Ornithine decarboxylase activity in ganglia from uncrushed nerves was the same in diabetic and non-diabetic rats. A significant (greater than 4-fold) increase in mean levels of ornithine decarboxylase activity 72 h after crush injury was found in ganglia from crushed nerves in non-diabetic but not in diabetic rats. The enzyme activity in ganglia from diabetic rats treated with insulin resembled that in non-diabetic rats. Twenty-four hours after crush injury, ornithine decarboxylase activity in ganglia from crushed nerves was higher in non-diabetic than in diabetic animals. This may be responsible for the delayed and defective nerve regeneration known to occur in peripheral nerve of the streptozotocin-diabetic rat.