The cerebral redox state in cats during severe insulin induced hypoglycemia

The cerebral metabolic state was studied in cats during insulin-induced hypoglycemia and the recovery after glucose infusion. Changes in the redox state of nicotinamide adenine dinucleotide (NAD) were monitored from the surface of the exposed cerebral cortex using microfluorometry. After insulin injection blood glucose fell from 6.85 mumol/ml to 0.45 mumol/ml at EEG isoelectricity and was accompanied by an oxidation of NADH+. Upon intravenous glucose infusion EEG activity rapidly returned and NAD became more reduced. The oxidation of NADH+ during severe hypoglycemia demonstrated that the in vivo redox state of mitochondria behave in a similar manner as isolated mitochondria when reducing equivalents become limiting to the respiratory chain.