Reduction of blood glucose levels and increased availability of energy for muscle contraction. Conversion of glucose into glycogen is increased. The glucose that isn't needed immediately for energy to power muscle contraction will be stored as glycogen. The key enzyme that speeds this process is glycogen synthase. Increased entry of amino acids from the blood.
Amino acids are the building blocks of protein.
Once inside the muscle most of them are sent to ribosomes where the manufacture of various muscle protein will take place. Overall Effects of Insulin on Muscle and Fat Decreased breakdown of existing muscle proteins into glucose. This effect of insulin along with each of the above is essential to the muscle's ability to grow and maintain itself. Insufficient insulin causes the reverse of all of the above. The severity of the reversal is proportional to the severity of the insulin deficiency.