Abstract
In the course of gluconeogenesis from hepatic proteins, the activities of lysosomal cysteine proteinases, such as cathepsins B, L, H and J(C) and deaminating enzymes, such as alanine aminotransferase were changed coordinately. When rats were placed on sufficient starvation, the both activities of cathepsins and aminotransferases in the liver were significantly elevated. Furthermore, the activity of hepatic cathepsin L increased markedly by glucagon treatment and insulin treatment caused marked decrease in the activities of cathepsins L and H. The changes in these cathepsin activities by the starvation or the hormone treatments may resulted in the increase of protein amounts judging from Western blotting analysis. The administration of prednisolone caused marked induction of alanine aminotransferase, however the level of hepatic cathepsins was not changed. The glucocorticoid may participate in the regulation of gluconeogenesis from amino acids digested from dietary proteins.
