Effects of fasting and glucose-insulin-potassium on glycogen contents in heart, skeletal muscle and liver

Abstract

The effect of intravenous infusion of glucose, insulin and potassium (GIK) on the glycogen contents of the heart, skeletal muscle and liver was investigated in rats. One group of animals received intravenous infusion of GIK continuously for 3 days, and two other groups of rats were given the same amount of saline intravenously. The animals receiving GIK, and a control group of the rats, were fasted for 8 h before sacrifice, while a second control group of animals was given free access to water and pellets until sacrifice. The heart, rectus femoris muscle and liver were then analysed for glycogen contents. It was found that fasting caused a depletion of glycogen in skeletal muscle and liver, while it did not cause any changes in myocardial glycogen which remained similar to that in the fed animals. Infusion of GIK prevented the depletion of glycogen in skeletal muscle and liver, but, unexpectedly, it did not cause any significant changes in myocardial glycogen content.

Key Words:

• glucose
• glycogen
• heart
• insulin
• liver
• skeletal muscle