Effect of chronic administration of fenfluramine and quipazine on body weight gain after ovariectomy and on brain serotonin receptor binding.

Chronic fenfluramine administration prevented excess weight gain following ovariectomy in rats but did not alter weight gain in sham-operated controls. Chronic quipazine treatment had no long-term effect on body weight. In one experiment, fenfluramine treatment for 28 days produced a 13% decrease in [3H]-serotonin binding to hypothalamic membranes and no change in [3H]-spiroperidol binding to striatum. In a second experiment, however, chronic fenfluramine had no effect on [3H]-serotonin binding to diencephalon. These results are discussed in terms of central and peripheral mechanisms of action and tolerance to fenfluramine.