Inhibition of Hypoglycemia-Induced Growth Hormone Secretion by the Serotonin Antagonists Cyproheptadine and Methysergide

Effect of Adrenergic-blocking Agents on Plasma Growth Hormone Response to L-5-Hydroxytryptophan (5-HTP) in Man

“…Although the metabolism of 5-HTP given orally in man has not been elucidated yet, it can be assumed from animal experiments (Corrodi et al, 1967) that 5-HTP raises serotonin content of the serotoninergic neurons in the human brain. An antiserotoninergic agent, cyproheptadine, is known to inhibit plasma hGH response to 5-HTP, arginine (Nakai et al, 1974) and insulin-induced hypoglycemia (Bivens et al, 1973). These results suggest that the serotoninergic mechanism is involved in the secretion of growth hormone in man.…”

Inhibition of insulin and glucagon release from the perfused rat pancreas by cyproheptadine (Periactinol�, Nuran�)

“…The hypothesis is supported by the finding that cyproheptadine reduced arginineinduced glucagon release. In addition, cyproheptadine is known to diminish the secretion of human growth hormone and cortisol [9,10,11]. Thus a general property to inhibit hormone release may be attributed to the agent.…”

“…Acute hyperglycemia after single injections of cyproheptadine, accompanied by a decrease of plasma insulin, was observed in the rat [5] and in the Syrian hamster [6]. In addition, in vitro experiments using the perfused rat pancreas [5], isolated islets [7,8], and pieces of Syrian hamster pancreas [6] revealed the inhibitory effect of cyproheptadine on insulin release.To gain further insight into this inhibition we investigated the effects of cyproheptadine on insulin release as caused by various stimulators and effectors.Cyproheptadine has also been reported to inhibit growth hormone (HGH) secretion [9,10] and cortisol release [11], suggesting that cyproheptadine has a general inhibitory effect on hormone release. Thus we studied the effects of cyproheptadine on the arginineinduced glucagon release by the perfused rat pancreas.…”

“…Cyproheptadine has also been reported to inhibit growth hormone (HGH) secretion [9,10] and cortisol release [11], suggesting that cyproheptadine has a general inhibitory effect on hormone release. Thus we studied the effects of cyproheptadine on the arginineinduced glucagon release by the perfused rat pancreas.…”

Neuroendocrine markers of CNS drug effects.

“…Diazepam has been shown to reduce ACTH output in man (Rees, 1970) and to reduce basal cortisol secretion in animals at low doses although in high doses cortisol secretion in animals is increased (Barlow, Knight & Sullivan, 1979 This finding has been replicated in patients with many diagnoses (General Practitioner Clinical Trials, 1970) and although the drug has been used in the treatment of anorexia nervosa systematic studies of its value in that condition have been few (Halmi & Goldberg, 1978). Endocrinological effects of cyproheptadine in man have been little studied but it has been found to reduce the growth hormone response to hypoglycaemia in normal volunteers (Bivens, Lebovitz & Feldman, 1973) and to suppress sleep related GH and cortisol release (Chihara, Kato, Maeda, Matsukara & Imura, 1976 (1979). Studies confined to particular disorders concern acromegaly (Thorner, Chait, Aitken, Bender, Bloom, Mortimer, Sanders, Stuart-Mason & Besser, 1975), Huntington's chorea (Caraceni et al, 1977) and Parkinsonism (Parkes, Debono & Marsden, 1976).…”