Possible role of oxidized glutathione for the regulation of the myocardial hexose monophosphate shunt.

Infusion of the isolated perfused Langendorff rat heart with tert-butyl hydroperoxide (3 X 10(-4) M) resulted in a marked enhancement of the concentration of oxidized glutathione, in an increase of the NADP+/NADPH ratio, and in an elevation of the available pool of 5-phosphoribosyl-1-pyrophosphate, which is one of the end products of the hexose monophosphate shunt. Since it has been shown that oxidized glutathione overcomes the inhibition of glucose-6-phosphate dehydrogenase exerted by NADPH, these results suggest that the myocardial hexose monophosphate shunt can be stimulated rapidly and markedly through this control mechanism.