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Gastrointestinal and metabolic consequences of a rat's meal on maintenance diet ad libitum
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posted on 2023-06-08, 22:19 authored by J C Newman, D A BoothThe gastric emptying of normally sized chow meals taken after minimal food deprivation appeared to be almost constant in rate for most of the period of emptying, although a short initial acceleration was not excluded and a slowing was generally observed late in emptying. Intestinal contents of dry matter and carbohydrate remained about constant and so under these conditions absorption rate equalled the recent gastric emptying rate. When the rat's meals are frequent, in the dark period of the 24 hour, the stomach emptied much more rapidly. When measured post mortem in groups of rats, blood concentrations of glucose did not vary markedly after a meal in the dark period, nor did blood concentrations of alanine, glycerol and other gluconeogenic precursors. An increase in rates of cerebral glucose uptake and conversion to glutamate and lactate was occasionally observed after meals, by comparisons of specific activities 5 min after subcutaneous injection of U-14C-glucose, but the increase was not regionally localised. Hepatic glycogen concentration did not vary up to the time the next meal would have been taken in the mid dark period. However, gluconeogenic capacity was reduced by 20–30% for about 90 min following the meal, as measured by conversion of a loading dose of 14C-alanine to 14C-glucose in blood. Gluconeogenesis or regulation of hepatic glucose output may protect the brain and other tissues, including even the liver, from the minor and brief variations in absorption between meals ad lib. Normal satiety and hunger may be anticipatory responses, established by the metabolic and/or hormonal consequences of occasional bursts or drops in absorption rate.
History
Publication status
- Published
Journal
Physiology and BehaviorISSN
0031-9384Publisher
ElsevierExternal DOI
Issue
5Volume
27Page range
929-939Department affiliated with
- Psychology Publications
Full text available
- No
Peer reviewed?
- Yes
Legacy Posted Date
2015-09-01Usage metrics
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