Feeding elicited by 2-deoxyglucose occurs in the absence of reduced glucose oxidation

We have previously reported that feeding in response to either systemic or intracerebroventricular administration of 2-deoxy-D-glucose (2-DG) persists for at least 6--8 h post-2-DG injection when the sympathoadrenal hyperglycemic response to glucoprivation has abated. This delayed feeding response to 2-DG suggests either that ongoing glucoprivation is not necessary for feeding or that responses such as hyperglycemia abate while glucoprivation is still extant and able to stimulate feeding. In order to determine whether glucoprivation is still present after the sympathoadrenal hyperglycemic response to 2-DG has abated, we measured systemic 14CO2 evolution and glucose oxidation in Sprague-Dawley rats treated with 2-DG (200 mg/kg) 0.5 and 6 h earlier. In addition, we measured cerebral 14C-2-DG accumulation in rats treated with unlabelled 2-DG 6 h prior to tracer administration We found that 14CO2 evolution and glucose oxidation were reduced by 47 and 667%, respectively, during the first 3.5 h post-2-DG but were normal by 6 h post-2-DG. Furthermore, we found that the uptake of 14C-2-DG into the brain was not diminished between 6 and 7 h after administration of unlabelled 2-DG. These results suggest that ongoing reduction of systemic glucose oxidation and ongoing impairment of hexose availability to the brain need not occur during 2-DG-induced feeding.