Calcium Transport in the Streptozotocin Diabetic Rat: Studies with Brush Border Membrane Vesicles

Abstract

Streptozotocin (Sz) diabetes in the rat is an experimental animal model for examination of pathophysiology of diabetes mellitus. When Sz-diabetes is induced in the young, rapidly growing rat, abnormalities of calcium homeostasis are to be anticipated. Sz-diabetes leads to growth arrest and hyperphagia, i.e. the major pathway of calcium utilization, bone growth, is blocked, in the setting of excessive intake of dietary calcium. Although growth arrest characterizes the organism as a whole, the alimentary tract, particularly the small intestine, grows (Jervis and Levin, 1966; Schedl and Wilson, 1971a, 1971b; Schedi et al, 1982). During the first 2–3 days after Sz injection, food intake is decreased. Subsequently, with restoration of food intake and development of hyperphagia, the alimentary tract grows. Crypt cell proliferation rate of jejunum and ileum in the Sz-diabetic rat is double that of the control (Miller, et al, 1977). This increased rate of cell division is present in Sz-diabetics pair-fed with controls, and is minimally increased by the hyperphagia of the ad lib fed diabetic, although mucosal mass of the entire small intestine is significantly greater in the ad lib as compared with the pair-fed Sz-diabetic (Schedl, et al, 1982).