Premium
Dopaminergic System Mediation of Stimulatory Effect of Melatonin on Secretion of Prolactin
Author(s) -
Okada Masataka
Publication year - 1995
Publication title -
journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.597
H-Index - 50
eISSN - 1447-0756
pISSN - 1340-9654
DOI - 10.1111/j.1447-0756.1995.tb01030.x
Subject(s) - melatonin , dopaminergic , prolactin , secretion , mediation , endocrinology , medicine , neuroscience , dopamine , biology , hormone , political science , law
Objective : The purpose of the present study was to clarify the mechanism of the stimulatory effect of melatonin on the secretion of prolactin. Methods : Determination was made of the levels of dopamine (DA), 3,4‐dihydroxyphenylacetic acid (DOPAC), serotonin (5‐HT), and 5‐hydroxyindoleacetic acid (5‐HIAA) in the median eminence of rats following intravenous melatonin (100 μg) administration. Results : Administration of 100μg of melatonin to rats resulted in a significant increase in prolactin secretion (p < 0.01, analysis of variance). Administration of melatonin also resulted in significant decreases in the DOPAC content (p < 0.05) and in the DOPAC/DA ratio (p < 0.05) in the median eminence 1 hour after melatonin administration, at which time serum prolactin was maximal. However, no significant changes were detected in the content of 5‐HT or 5‐HIAA or in the 5‐HIAA/5‐HT ratio in the median eminence. Conclusion : These results suggest that the stimulatory effect of melatonin on the secretion of prolactin might be mediated by dopaminergic mechanisms.