Possible dopaminergic system involvement in LH and PRL responses to naltrexone treatment

L. Yogev*, A. Gottreich, Z. T. Homonnai, G. F. Paz

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Naltrexone (Nalt) causes a rapid increase in luteinizing hormone (LH) level. This short term increase of LH concentration declines to baseline levels in less than 1 hour. Addition of pimozide (0.1 mg) caused a blunted response to Nalt challenge, with significantly Pimozide reduced LH peak values compared with Nalt treatment alone. Pimozide alone caused a delayed decrease compared with baseline LH values. By following plasma prolactin (PRL) levels it was shown that pimozide administration increased PRL levels rapidly for more than 2 hours. Addition of Nalt to pimozide-treated rats significantly decreased plasma PRL values compared with pimozide alone. Nalt injected by itself attenuated PRL baseline levels. Thus, the mechanism by which pimozide caused PRL elevated level is via the dopaminergic as well as the opioid system. It is suggested that the opioid system controls plasma PRL and LH levels through other hypothalamic neurotransmitters in addition to dopamine.

Original languageEnglish
Pages (from-to)2343-2349
Number of pages7
JournalLife Sciences
Issue number24
StatePublished - 1989
Externally publishedYes


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