Digestibility in male rats with lateral hypothalamic lesions.

The body weight of male rats with lateral hypothalamic lesions remained approximately 20% below that maintained by nonlesioned controls. One month following surgery, both food intake and energy losses in feces and urine were measured in all animals for five days. The percentage of ingested food absorbed by the gut ("digestibility") was determined from calorimetric analysis of the feces to be slightly, though significantly, higher for the lesioned animals (79.7% vs 77.4%). Resorptive capacity, as indicated by the percentage of absorbed energy lost in the urine, was determined to be the same for the lesioned and control animals (4.8% vs 4.5%). These results indicate that the digestive, absorptive, and resorptive processes of LH-lesioned animals are at least as efficient as those of nonlesioned animals maintaining normal body weights. Thus, though LH-lesioned animals are reported to display various gastrointestinal dysfunctions, alterations in digestive or resorptive efficiency are apparently not responsible for their chronically-reduced body weights.