The apparent effect of melatonin on glucose homeostasis in the liver

Abstract

The addition of insulin to incubated liver slides gives rise to a decrease in the glucose concentration of the incubation medium. Should melatonin be added simultaneously, the effect of the insulin alone would be almost totally neutralised. The addition of glucagon to incubated liver slides has no effect on the glucose concentration of the incubation medium. Should melatonin be added simultaneously, the glucose concentration would rise considerably. It would appear that melatonin in liver tissue serves as an insulin antagonist/glucagon synergist.