Glycemic control and not protein kinase C inhibition prevents the early decrease of glutathione peroxidase activity in peripheral nerve of diabetic mice

Experimental diabetes promotes changes in biochemical activities of periphe ral nervous tissue. Glutathione peroxidase activity decreases in sciatic ne rve of diabetic mice very early after onset of experimental diabetes. Effec tive glycemic control with insulin restores the early lost glutathione pero xidase activity in peripheral nerve of diabetic mice to control values. Dat a are also presented demonstrating that glutathione peroxidase activity in diabetic mouse peripheral nerve is not modified by the constant delivery of calphostin C, a protein kinase C inhibitor, therefore this decrease seems to be independent on a protein kinase C mediated mechanism. Thus, the early glutathione peroxidase activity decrease in peripheral nerve of diabetic m ice is closely related to hyperglycemia, and a tight glycemic control is ra ther effective in restoring the control levels of this enzymatic activity. The results herein do not rule out the benefits of antioxidant adjuvant the rapies in diabetes to help recover the overall decrease in antioxidant defe nse in peripheral nerve elicited by the decrease of glutathione peroxidase activity.