The effect of a high-fat diet on brainstem and duodenal serotonin (5-HT) metabolism in Sprague-Dawley and Osborne-Mendel rats.

Sprague-Dawley (S-D) and Osborne-Mendel (O-M) rats were fed either a low-fat diet (5 percent corn oil) or high-fat diet (20 percent corn oil) for a six-week-period. Brainstem and duodenal levels of tryptophan, serotonin (5-hydroxytryptamine, 5-HT) and 5-hydroxyindole-3-acetic acid (5-HIAA) were not altered by dietary treatment in the O-M rats. On the other hand, the high-fat diet significantly decreased brainstem 5-HT levels in S-D rats. Brainstem and duodenal 5-HT levels were decreased in O-M rats as compared to S-D rats and this phenomenon is not altered by dietary treatment. It is suggested that the O-M rat may have a alteration in the 5-HT metabolic system and that such a defect may contribute to the development of obesity.