Anabolism versus catabolism Anabolism is the building up of body components, while catabolism is their destruction. All live animals show both anabolism and catabolism. If anabolism exceeds catabolism, the animal is growing. If catabolism exceeds anabolism, the animal is wasting away. If anabolism equals catabolism, animal weight is constant.
Protein turnover is the time between anabolism and catabolism of an individual protein.
For meat animals, the half-lives of the important meat proteins are around several days in length, with muscle proteins being much faster than connective tissue proteins. In the muscles of young animals, both the rates of protein synthesis and degradation are faster than in older animals. In the muscle tissue of growing animals, insulin is the most important factor that inhibits the degradation of myofibrillar proteins when anabolism exceeds catabolism. Epinephrine and serotonin have similar but minor effects. In fasting animals, where catabolism exceeds anabolism, proteolysis is promoted by glucocorticoids.