Conditioned Hypoglycemia: A Mechanism for Saccharin-Induced Sensitivity to Insulin

Abstract

<p>Evidence was presented in Experiment I which replicated previous findings, indicating that ingestion of the non-nutritive sweetener, saccharin, potentiates insulin-induced mortality in rats. Five additional experiments were conducted to determine the mechanism for this effect. The specific hypothesis examined was the view that saccharin ingestion augments the effect of insulin because the taste of saccharin elicits a conditioned hypoglycemic response. Since glycemic metabolic events have in the past been contingent on the preceding gustatory sensations associated with the ingestion of sweet nutritive substances, sweet taste alone may elicit these glycometabolic events as a conditioned preparatory response, thus leading to a reduction in blood glucose level. The present research has shown that saccharin ingestion alone results in hypoglycemia, and that this response is extinguished by long-term access to saccharin, but not by long-term access to glucose (a nutritive sweet substance). Furthermore, it was demonstrated that the hypoglycemic response can be elicited by stimuli, either gustatory or olfactory, which have been specifically paired with direct intragastric administration of glucose. These results were interpreted as supporting the conditioning account of the potentiating effect of saccharin on insulin-induced mortality. Such conditioning has implications for predicting the organism's response to drugs with glycometabolic actions, and, more generally, points out the importance of conditioned preparatory responses in the digestion and utilization of food.</p>