The effect of infused nutrients and absorbed foods on daily food intake in rats.
Studies with crossed intestines rats show that daily food intake is controlled by internal signals that arise at the level of the small intestines or from the absorption of food into the bloodstream and its subsequent metabolism. The gut can produce endogenous signals such as neural messages responding to the presence of nutrients in the wall of the small intestine or in the portal vein leading to the liver. GI hormones can be released from various regions of the small intestine and may partially inhibit food intake. When nutrients bypass the gut and are infused indirectly into the bloodstream, they produce a partial 50% to 80% compensation for the number of calories infused. Clearly, nutrients play a major role in the control of daily intake. Infusion of these nutrients into specific vascular sites suggest that they do not act directly on the brain or the liver to reduce daily intake. Cross-circulation studies suggest that the combination of hormones and nutrients do not affect intake during a single meal. It is possible that nutrients act directly on the gut to inhibit stomach emptying or on the storage tissues, such as muscle or fat, to control daily food intake.
Koopmans
H S
HS
Department of Medical Physiology, University of Calgary, Alberta, Canada.
D000818:Animals; D004435:Eating / Q000502:physiology*; D006706:Homeostasis; D007408:Intestinal Absorption; D007422:Intestines / Q000502:physiology / Q000601:surgery; D010288:Parenteral Nutrition; D051381:Rats