Failure of 5-Hydroxytryptophan to Stimulate Prolactin and Growth Hormone Secretion in Man

Handwerger, Stuart; Plonk, James W.; Lebovitz, H. E.; Bivens, Carl H.; Feldman, J.

doi:10.1055/s-0028-1093741

Cited by 44 publications

(10 citation statements)

References 4 publications

(4 reference statements)

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“…In man, 5-HTP given orally either alone (Miiller et al, 1974) or in combination with a peripheral decarboxylase inhibitor (Benkert et al, 1973;Handwerger et al, 1975) failed to induce plasma GH changes. Oral administration of TP in man (Miiller et aI., 1974;Woolf and Lee, 1977) and dogs (MiilIer et aL, 1976) induced only a slight rise in plasma GH titers in few of the subjects studied.…”

Section: Discussionmentioning

confidence: 96%

Neuroendocrine effects of quipazine in man in health state or with neurological disorders

Parati

Zanardi

Caraceni

et al. 1980

J. Neural Transmission

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The endocrinological actions of quipazine, a direct serotonin receptor agonist, were investigated in both normal subjects (NS) and individuals with neurological disorders, i.e., Huntington's disease (HD), myoclonic epilepsy (ME) and cluster headache (CH). In both normal subjects and neurologic patients inconsistent and variable changes in the secretion of anterior pituitary hormones were observed. In fact, oral administration of 50 mg of quipazine elicited a rise in plasma GH in only 9/23 subjects investigated (3 NS, 2 HD, 1 ME, 3 CH), decreased GH in 4 subjects (1 NS, 2 HD, 1 CH) and left unmodified plasma GH in the remaining 10 subjects. Only 7/23 subjects showed a positive PRL response to quipazine (2 NS, 1 HD, 1 ME, 3 CH), in one subject (CH) PRL was inhibited while the drug was ineffective in the remaining 15 subjects. For gonadotropins, 5/21 subjects (2 NS, 1 HD, 2 CH) had a positive LH response and 3/20 subjects (1 NS, 1 ME, 1 CH) had a positive FSH response. In one subject (HD) there was inhibition of baseline LH levels and no effects were present in the remaining individuals. No changes in basal TSH levels were present in the 6 subjects investigated (4 NS, 2 ME). Quipazine was instead competent to increase plasma cortisol levels in 6/8 normal subjects. Pharmacodynamic, mainly gastrointestinal, effects of the drug were present in about 50% of the subjects but were not or only poorly correlated with the endocrine responses. Collectively, based on the neuropharmacologic profile of the drug, and in contrast to many animal data, these findings do not support a major role for the serotoninergic system on basal anterior pituitary hormone secretion in man, possibly with the exception of the ACTH-cortisol secretion.

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Section: Discussionmentioning

confidence: 96%

Neuroendocrine effects of quipazine in man in health state or with neurological disorders

Parati

Zanardi

Caraceni

et al. 1980

J. Neural Transmission

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“…Kato et al (1974) found that oral 5-HTP administration was able to significantly increase PRL release in healthy subjects and Woolf & Lee (1977) observed a significant elevation of plasma PRL levels when the administration of tryptophan was followed by a water load. On the other hand, Handwerger et al (1975), , Wiebe et al (1977), by giving 5-HT precursors, failed to show modifications of PRL release. Similar results have been obtained in man by Parati et al (1980) with quipazine, a 5-HT agonist.…”

Section: Introductionmentioning

confidence: 99%

Prolactin secretion in man: a useful tool to evaluate the activity of drugs on central 5‐hydroxytryptaminergic neurones. Studies with fenfluramine.

Quattrone¹,

Tedeschi²,

Aguglia³

et al. 1983

Brit J Clinical Pharma

157

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1 Acute oral administration of various doses of fenfluramine, a 5-HT releaser, induced a doserelated increase of PRL secretion in nine healthy volunteers. 2 Fenfluramine reached the maximum effect on PRL secretion at 4 h after its administration. This effect was already significant at 2 h and lasted till 8 h. 3 Metergoline, a 5-HT receptor blocker, when administered alone, decreased serum PRL levels in six healthy subjects. The pretreatment with this drug significantly antagonized the PRL-releasing action of fenfluramine (60 mg) suggesting that the effect of fenfluramine on PRL release may be mediated through a 5-HT mechanism in the brain. 4 These findings suggest the possibility that serum PRL levels in humans may represent a useful tool to evaluate, in vivo, the activity of drugs possessing putative 5-hydroxytryptaminergic properties.

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“…[Pühringer et al, 1976] administration of 5-HTP. However, in other studies, oral administration of 5-HTP given either alone [Müller et al, 1975] or in combination with a peripheral decarboxylase inhibitor [Benkert et al, 1973;H andwerger et al, 1975] failed to induce plasma GH changes.…”

mentioning

confidence: 99%

Effect of 5-Hydroxytryptophan on Prolactin and Growth Hormone Release in the Infant Rat: Evidence for Different Neurotransmitter Mediation

Cocchi¹,

Gil-Ad²,

Panerai³

et al. 1977

Neuroendocrinology

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In 10 day-old female and male rats, administration of 5-hydroxytryptophan (5-HTP) induced a prompt elevation in plasma prolactin (Prl) and growth hormone (GH) levels. Pretreatment with 2 serotonin (5-HT) receptor blockers, methysergide (Meth) and metergoline (MCE), markedly reduced the 5-HTP-induced Prl rise but failed to alter the GH response to 5-HTP. Administration of 2 selective inhibitors of presynaptic 5-HT reuptake, 3-(p-trifluoromethylphenoxy)-N-methyl-3-phenyl-ρropylamine and chlorimipramine (CIM), potentiated the 5-HTP-stimulated Prl rise but significantly reduced the 5-HTP-induced GH release. Blockade of dopaminergic or α-adrenergic receptors by pretreatment with pimozide (Pim) or phentolamine (Phent), respectively, or central sympathectomy by intraventricularly (i.vt.) injected 6-hydroxydopamine (6-OHDA) were capable of reducing the 5-HTP-induced GH release without affecting the 5-HTP-induced Prl rise. These data indicate that in the infant rat the 5-HTP-induced Prl release is mediated via the brain 5-HT system and that a nonspecific activation of the catecholaminergic system is responsible for the GH response to the drug.

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Failure of 5-Hydroxytryptophan to Stimulate Prolactin and Growth Hormone Secretion in Man

Abstract: in experimental diabetes of the rat. 111. Studies in allogeneic streptozotocin-treated rats (in prep.

Cited by 44 publications

References 4 publications

Neuroendocrine effects of quipazine in man in health state or with neurological disorders

Neuroendocrine effects of quipazine in man in health state or with neurological disorders

Prolactin secretion in man: a useful tool to evaluate the activity of drugs on central 5‐hydroxytryptaminergic neurones. Studies with fenfluramine.

Effect of 5-Hydroxytryptophan on Prolactin and Growth Hormone Release in the Infant Rat: Evidence for Different Neurotransmitter Mediation

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