Postalimentary hyperthermia: a role for gastrointestinal but not for caloric signals

(1) Fasting causes suppression of resting body temperature (T-c) and metabo lic rate (MR) in rats. (2) Re-feeding with conventional chow or saccharine- sweetened CaCO3 elevates MR and T-c of fasting rats. It is not the composit ion, but the volume of ingested substance that is important. (3) MR- and T- c-elevations have different dynamics following injections of calorie-rich o r -free substances through an intragastric cannula. (4) Intravenous infusio ns of 40% glucose or 20% fat emulsion do not influence MR and T-c. (5) Gast rointestinal, rather than caloric, signals determine the postalimentary hyp erthermia. (C) 2001 Elsevier Science Ltd. All rights reserved.