Gastrointestinal satiety in animals other than man.

The present paper reviews the development of some of our ideas of how physiological stimuli on the gastrointestinal tract contribute to the onset of satiety. The various signals originating from the gut caused by stretch, osmo-concentration or specific chemical stimuli must be relayed to the brain, either neurally or hormonally, to be integrated with post-absorptive signals from other sites including the brain itself. to produce a response, which will also take into account the animal’s previous experience. the importance of the different signals varying with the feeding regimen. In free-feeding animals, individual meal size varies and relatcs to the succeeding inter-meal interval (Le Magnen, 1983). so that long-term intake can be adjusted by the number of meals. In animals that are meal-fed once or twice daily, long-term intake relates to meal size, which must involve a learned anticipation of metabolic requirements. As the meal terminates long before absorption is complete, meal size will be largely signalled from the gastrointestinal tract.