THE EFFECT OF INTRAGASTRIC ETHANOL ON MEAL SIZE IN THE RAT

Although ethanol is a calorically dense substance, little is known abo ut the mechanisms by which those calories are detected, nor how they e ffect subsequent intake of other calories. In the current study, four doses of ethanol (0, 1, 2, and 3.5 g/kg) were administered to rats pri or to 30-min access to a sucrose solution. The effect of ethanol (EtOH ) to impact sucrose intake was compared to that of another carbohydrat e, glucose, matched for calories, and to NaCl solutions matched to the osmotic properties of the glucose. A final set of conditions provided calories in the form of EtOH as well as osmoles in the form of NaCl t o match the combined caloric and osmotic properties of the glucose sol utions. Aqueous solutions of EtOH and of glucose suppressed food intak e in a dose-dependent fashion with glucose tending to be more effectiv e than EtOH. NaCl in water did not suppress intake. Surprisingly, when NaCl was added to the EtOH solution the effect of EtOH to suppress fo od intake was completely ameliorated. Subsequent analysis of plasma Et OH levels showed that adding NaCl also reduced the rate at which EtOH appeared in the plasma. The results suggest that changes of short-term food intake caused by EtOH calories are produced by different inhibit ory signals than those produced by other carbohydrates. While other ca rbohydrates generate preabsorptive signals within the stomach, ethanol appears to have to leave the stomach to inhibit further fool intake. Copyright (C) 1997 Elsevier Science Inc.