Changes in the activity of salivary gland cathepsins in the course of alloxan-induced diabetes mellitus in rabbits

Though there is a significant similarity in structure between the parotid gland and the pancreas, less is known about the submandibular glands in the course of diabetes mellitus. Our aim was to quantify any changes in the level of bound and unbound cathepsin B, D, and L in the course of alloxan-induced diabetes mellitus. Rabbits were divided into a control group and groups injected with alloxan on the 21st, 42nd, 90th and the 180th day, after which blood samples were taken and the rabbits killed by decapitation. The right parotid and submandibular gland were removed and the glucose level measured. The activities of enzymes changed over the course of experiment, most markedly those of free fraction of cathepsin B and D in the parotid gland. The activity of bound cathepsin L, in the parotid gland was much higher in all groups in relation to the free fraction. We conclude that the activity of cathepsin B, and to a lesser degree cathepsin D, in the parotid gland correlated inversely with the level of glucose. Secondly, we established that the activity of the bound fraction of cathepsin L in the submandibular gland was significantly elevated in the early stages of diabetes. (C) 1998 Lippincott Williams & Wilkins.