MEAL PATTERNS AND PLASMA LIVER-ENZYMES AND METABOLITES AFTER TOTAL LIVER DENERVATIONS

The liver by way of afferent nerves has been suggested to be a controller of food intake. However, long term meal pattern analysis of chow intake by rats has revealed that total liver denervation (TLD) did not affect the patterns. Nevertheless, these studies have been criticized because they may have missed initial subtle difference in meal patterns that were corrected later by redundant mechanisms. TLD also can alter physiological regulator mechanisms that could secondarily affect feeding behavior. Furthermore, the TLD procedure itself can produce pathologic changes if extreme care is not taken; if pathology does occur it could subsequently affect food intake measurements. In Experiment 1, male rats were given TLD or sham operations (SHAM) at the beginning of the light phase and food withheld until the onset of the dark period. Using a computer operated system, postsurgery onset to feeding, meal size, duration, and frequency were found to be comparable between the groups from the first meal onward. In Experiment 2, 21 days after TLD or SHAM feeding patterns were recorded; all meat parameters were similar between the groups. The rats were then killed and plasma analyzed for liver enzymes (a reflection of liver damage), nutrients and metabolites; no differences were found between the groups. The data suggests that TLD doesn't affect normal regulation of chow intake from the rats' first postsurgery meal onward. The second study showed that the TLD technique, in our hands, did not produce an adverse effect on normal liver function.