Effect of high-altitude hypoxia on feeding responses and hedonic matrix in rats

Albino male rats (n = 78) were exposed to a simulated high altitude (HA) equivalent to 7,620 m for 6 h daily, contiguously for a period of 21 days, to study their feeding behavior and gustatory responses. Their food, water intake, and body weight were recorded daily, and blood sugar and blood insulin were estimated once a week. All the parameters were recorded for a period of 3 wk each before, during, and after exposure to simulated HA. The results show a decrease in daily food and water intakes and body weight and mild hyperglycemia and hyperinsulinemia during hypoxic exposure. The 1-h single-bottle taste solution test showed a preference for sweet solutions (13% glucose and 0.2% saccharine) over citric acid (0.16%), sodium chloride (0.9%), and quinine sulfate (0.001%) during exposure to simulated HA. The 1-h two-bottle test containing glucose (calories plus taste) and saccharine (taste but no calories) administration showed a preference for the glucose solution over the saccharine solution. The trend of the 1-h intake of all test solutions also showed a reversal to preexposure levels after termination of HA hypoxia. It would appear that high-altitude stress influences food intake in a manner that sensory cues (e.g., preference for sweet substances) become more important.