Effects of melatonin in vivo upon luteinizing hormone and prolactin releases induced by opiate receptor antagonists in adult male rats
| Autor: | B. Rault, B. Saiag, V. Lemay, V. Shacoori, A. Girre |
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| Rok vydání: | 1996 |
| Předmět: |
Male
endocrine system medicine.medical_specialty medicine.drug_class Narcotic Antagonists Endocrinology Diabetes and Metabolism (+)-Naloxone Pharmacology Melatonin Endocrinology Opioid receptor Internal medicine medicine Animals Rats Wistar Nalmefene Naloxone Chemistry Narcotic antagonist Luteinizing Hormone Naltrexone Prolactin Rats Quaternary Ammonium Compounds Luteinizing hormone hormones hormone substitutes and hormone antagonists Opioid antagonist medicine.drug |
| Zdroj: | Journal of Endocrinological Investigation. 19:76-82 |
| ISSN: | 1720-8386 0391-4097 |
| DOI: | 10.1007/bf03349840 |
| Popis: | The effects of melatonin on LH and PRL releases induced by treatment with naloxone, naloxone methyliodide and nalmefene were studied in adult male rats. Subcutaneous melatonin injection (1.4 mg/Kg) had no effect on LH secretion, but caused an inhibition effect (84%) on LH release induced by naloxone (2.4 mg/Kg). Melatonin too totally inhibited LH secretion induced by naloxone methyliodide (2.8 mg/Kg) and nalmefene (2 mg/Kg) when it was simultaneously administered with each opioid receptor antagonist. Melatonin alone had no significant effect on serum PRL levels, but decreased by 25.5% the inhibitory effect potency of nalmefene on PRL secretion after simultaneous injections. The inhibitory effect potency of naloxone on PRL release increased (16%) when it was administered with melatonin. Simultaneous injection of melatonin with naloxone methyliodide inhibited PRL release (78%) while naloxone methyliodide alone did not modify this secretion. The results obtained with a quaternary opioid antagonist indicate that the opioid receptor type which mediates LH and PRL responses is located respectively outside and inside the blood-brain barrier. Our findings show that opiate antagonists and their quaternary ammonium salts affect secretion of LH and PRL through different mechanisms susceptible to the influence of melatonin. |
| Databáze: | OpenAIRE |
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