POSTINGESTIVE FACTORS INFLUENCING OPERANT SUGAR INTAKE IN PIGS

Intravenous injections of glucose, which increased plasma glucose leve ls to approximately 10 times the normal level, had no significant effe cts on the amount of glucose consumed in operant tests carried out imm ediately after the injection. The importance of gastrointestinal facto rs in regulating glucose intake was demonstrated in experiments in whi ch pigs with gastric cannulae sham drank significantly (p < 0.01) more glucose over a 1-h period than control sessions with the cannula clos ed. Intraduodenal injection of glucose or mannitol significantly reduc ed glucose intake, with glucose significantly (p < 0.05) more effectiv e than mannitol and both significantly (p < 0.01) more effective than water. Gastrointestinal factors are important in regulating sugar inta ke whereas blood sugar levels are not. The pig is a good experimental animal for the study of sugar appetite.