Do serotoninergic drugs decrease energy intake by reducing fat or carbohydrate intake? Effect of d-fenfluramine with supplemented weight-increasing diets.

The capacity of serotoninergic drugs to selectively suppress carbohydrate (CHO) intake was investigated using a procedure sensitive to drug action. The drug d-fenfluramine was administered chronically to rats whose weight had been increased by exposure to either a fat or CHO-supplemented hyperphagia-inducing diet. The drug exerted a more potent anorexic effect and weight-reducing action in rats given the dietary supplements than in control chow-fed rats. Tolerance to the drug was not apparent even after 40 days of treatment. However, there was no evidence for a selective inhibition of CHO intake, nor was the drug more potent with the CHO-supplemented diet. d-Fenfluramine was equally effective against the hyperphagia and weight gain induced by either fat or CHO supplements.