Glucoprivic feeding behavior in absence of other signs of glucoprivation

When rats were denied immediate access to food after subcutaneous injection of 2-deoxy-D-glucose (2DG), the glucoprivically induced sympathoadrenal hyperglycemia subsided spontaneously within 6 h. However, if food was returned to the rats 6 h after 2DG injection, they still ate significantly more than after saline control injections. Rats injected with insulin also increased their feeding even when food was withheld until the animals had returned to normoglycemia. Injections of exogenous glucose sufficient to elevate blood glucose concentrations above normal failed to inhibit increased feeding observed when food was returned 6 h after injection of regular insulin. These data show that 2DG and insulin-induced feeding can occur in the absence of overt signs of glucoprivation and suggest that the glucoprivic control may be operable in the day-to-day control of feeding when other signs of glucoprivation are not readily observable.