Research Projects

Redox potential of oxytocin <—> oxytoceine

Vitamin C (aka ascorbate) is another non-enzymatic antioxidant found in significant levels within the testes. As an antioxidant, ascorbate's primary role is to donate electrons to neutralize reactive species of oxygen including superoxide (to H2O2) and hydroxyl free radicals (to H2O). When ascorbate acts as a scavenger (by donating an electron to a free radical), ascorbate is oxidized in the process to the ascorbate free radical and dehydro-ascorbate. The ascorbate free radical and the dehydro-ascorbate are reduced back to ascorbate either by NADH (catalyzed by semidehydroascorbate reductase and forming NAD) or reduced glutathione (GSH)(catalyzed by dehydroascorbate reductase and forming oxidized glutathione (GSSG)).

n.b. Vitamin C also works along with glutathione peroxidase (a major free radical-fighting enzyme) to revitalize vitamin E.

Interestingly, Kukucka et. al. reported finding significant levels of oxytocin (a disulfide containing octapeptide) in isolated Leydig cells. Kukucka theorized in the introduction of his PhD dissertation that open chain oxytoceine (the reduced form of oxytocin) may also act as a scavenger (by donating an electron to a free radical), oxytoceine may then be oxidized back to oxytocin. As noted above, the ascorbate free radical and the dehydro-ascorbate are reduced back to ascorbate either by NADH catalyzed by semidehydroascorbate reductase (and forming NAD) or reduced glutathione (GSH) catalyzed by dehydroascorbate reductase (and forming oxidized glutathione (GSSG)).... why couldn't the ascorbate free radical and dehydro-ascorbate be reduced back to ascorbate by reduced oxytoceine (forming closed-ring oxytocin)?

Thus, the redox potential of oxytocin <---> oxytoceine may drive ascorbate <---> dehydro-ascorbate or vice versa as part of the non-enzymatic antioxidant defense system.

With that said:

Could the redox potential of oxytoceine drive the formation of reduced ascorbate and oxytocin.... is this chemistry right?

What is the redox potential of oxytocin <---> oxytoceine?

What is the redox potential of ascorbate <---> dehydro-ascorbate?