Effects of terguride on anterior pituitary function in parkinsonian patients treated with L-dopa: A double-blind study versus placebo

E. Martignoni, R. Horowski, A. Liuzzi, A. Costa, D. Dallabonzana, R. Cozzi, R. Attanasio, E. Rainer, G. Nappi

Research output: Contribution to journalArticle

Abstract

In a randomized double-blind study, 20 parkinsonian patients (suffering from the disease for 2-18 years), chronically treated with levodopa (500750 mg/day for 0.5-12 years), received terguride (1 mg b.i.d) or placebo for 4 weeks. Growth hormone (GH), prolactin (PRL), thyroid-stimulating hormone (TSH), and insulin-like growth factor (IGF-I) secretions were studied before and after the morning dose of levodopa 1250 mg p.o.), both before and at the end of study period. At the beginning of the study, basal hormonal levels were within normal limits, and levodopa administration induced a significant suppression in PRL and TSH levels (both p <0.01)) and a significant increase in GH (p <0.01). The same results were observed at the end of the study period in the placebo group. Addition of terguride induced a significant suppression in basal PRL levels (p <0.01), whereas levodopa-induced hormonal changes were unaffected. These data suggest that the hypothalamic dopaminergic function that controls anterior pituitary hormones is preserved in parkinsonian patients, regardless of both the duration of the disease and the long-term treatment with levodopa. The strong additional prolactin- lowering effect of terguride indicates long-lasting dopaminergic effects, as is already known from hyperprolactinemic conditions. The dopaminergic effects of levodopa on TSH, GH, and IGF-I secretion were unchanged by terguride treatment. The antidopaminergic effects of terguride observed in the motor system in animal studies, as well as in levodopa-induced dyskinesias in parkinsonian patients, could not be observed in the case of the dopaminergic control of anterior pituitary hormones trader the conditions of this study.

Original languageEnglish
Pages (from-to)72-80
Number of pages9
JournalClinical Neuropharmacology
Volume19
Issue number1
Publication statusPublished - 1996

Keywords

  • Dopamine agonist
  • Growth hormone
  • Hypothalamus
  • Parkinson's disease
  • Pituitary
  • Prolactin
  • Terguride
  • Thyroid-stimulating hormone

ASJC Scopus subject areas

  • Pharmacology (medical)
  • Clinical Neurology
  • Neuroscience(all)
  • Pharmacology, Toxicology and Pharmaceutics(all)

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  • Cite this

    Martignoni, E., Horowski, R., Liuzzi, A., Costa, A., Dallabonzana, D., Cozzi, R., Attanasio, R., Rainer, E., & Nappi, G. (1996). Effects of terguride on anterior pituitary function in parkinsonian patients treated with L-dopa: A double-blind study versus placebo. Clinical Neuropharmacology, 19(1), 72-80.