356 



p. TEITELBAUM AND A. N. EPSTEIN 



animal fed itself intragastrically for 41 days It can be seen that hyperphagic 

 animals continue to eat and become obese when they feed themselves 

 intragastrically. They can respond appropriately to dietary dilution of the 

 diet and will regulate intake by adjusting to the size of the individual 



INTRAGASTRIC 



15 20 25 

 DAYS 



Fig, 7. Body weight, daily food intake, the number of self-loads, and the 



number of daily responses during 2 days of oral food intake and 41 days of 



intragastric intake in the dynamic hyperphagic rat. 



stomach load. But in contrast with normal animals, they are quite sluggish 

 in demonstrating such intragastric regulation. Note that after the transi- 

 tion from oral to intragastric feeding, it took 7 days before the animal 

 was willing to work hard enough to overeat intragastrically. From the 

 1st to the 6th day of intragastric feeding, the animaFs voluntary intake 

 was markedly depressed. Normal animals typically make the transition 

 within the very first day of intragastric feeding. The inertia shown by 

 hyperphagic animals can be attributed to their impaired motivation for 

 food and reveals the importance of taste in maintaining adequate regula- 

 tion of their intake. 



When an animal is switched from oral feeding to intragastric feeding, 

 taste and smell are removed as a reinforcement from the diet. Normal 

 animals are sufficiently motivated to overcome the decrease in reinforce- 

 ment and therefore they continue to regulate their intake without lag when 

 feeding themselves intragastrically. Hyperphagic animals, however, with 



