Ingestion patterns of food, water, saccharin and sucrose in streptozotocin-induced diabetic rats.

Changes in preference for sweet tasting solutions have previously been reported in diabetic rats. The present study was designed to use detailed analyses of drinking patterns to investigate changes in sweet taste perception in rats made diabetic with a streptozotocin (SZ) injection and tested with saccharin and a broad range of sucrose concentrations. Although meal patterns in diabetic rats have been studied extensively, drinking patterns and their relation to meal patterns have not been described. A second goal of this research was to use the detailed patterns of eating and drinking of the diabetic rat in an effort to understand the resulting hyperphagia. Rats were given IP injection of SZ or saline. Following the SZ injection, the rats showed marked increase in blood glucose levels, an increase in food and fluid intake and they failed to gain weight. The SZ-injected rats showed a loss of preference for saccharin and for high concentrations of sucrose. Patterns of sucrose ingestion that are correlated with taste perception were distorted in the diabetic rats. The detailed pattern analysis of eating showed that the diabetic-induced hyperphagia resulted from a marked increase in length of eating bouts. The increase in fluid intake in the diabetic rats resulted from both an increase in frequency and length of drinking bouts. Circadian patterns of both food and fluid ingestion were maintained in the diabetic rats.