Effect of fenfluramine on human growth hormone release

In order to investigate the effect of fenfluramine on hormonal and metabolic changes with exercise, five normal volunteers have been studied during and after 20 minutes of steady exercise on a bicycle ergometer after injection of fenfluramine (20 mg intravenously). Fenfluramine abolished the rise of plasma human growth hormone (HGH) which occurred in control investigations. Fenfluramine also affected plasma insulin, blood glucose, and ketone body levels.The acute effect of fenfluramine on the release of growth hormone was examined further by studying its effect in patients with acromegaly. A marked depression of growth hormone occurred both at rest and with exercise. These observations indicate that fenfluramine has a direct effect on pathways controlling growth hormone release. We also suggest that this action may have practical use in the medical treatment of acromegaly.