Integrated metabolic control of food intake after 2-deoxy-D-glucose and nicotinic acid injection.
We measured the minute-to-minute respiratory quotient (RQ), total metabolic rate, and the intensity and energy cost of locomotor activity in unrestrained rats with a recently developed open-circuit metabolic device. These measures permitted calculation of the resting metabolic rate (designated métabolisme de fond or MF). Simultaneous monitoring of the meal patterns of the animals allowed correlations between MF and feeding behavior. The major hypotheses proposed to account for the onset of feeding were challenged by pharmacological inhibition of the utilization of glucose and/or lipids. When injected together, 2-deoxy-D-glucose, which blocks glucose utilization, and nicotinic acid, which blocks lipid utilization, had a synergistic effect on MF and on the feeding response. The RQ, which reflects the relative rate of glucose-to-lipid utilization, showed that neither the inhibition of utilization of glucose nor the inhibition of utilization of lipids could account for the magnitude of the feeding response. The signal that best accounted for these examples of experimentally induced feeding is ischymetric (power or rate of energy) in nature rather than solely glucostatic or solely lipostatic.
Even
P
P
Centre National de la Recherche Scientifique UA 637, Collège de France, Paris.
Coulaud
H
H
Nicolaidis
S
S
D000818:Animals; D003837:Deoxy Sugars / Q000494:pharmacology*; D003847:Deoxyglucose / Q000494:pharmacology*; D004435:Eating / Q000187:drug effects*; D004734:Energy Metabolism; D005260:Female; D009043:Motor Activity; D009525:Niacin / Q000494:pharmacology*; D010101:Oxygen Consumption; D051381:Rats; D011919:Rats, Inbred Strains; D012984:Software
D003837:Deoxy Sugars; D009525:Niacin; D003847:Deoxyglucose