Serotonin directly stimulates luteinizing hormone-releasing hormone release from GT1 cells via 5-HT7 receptors.
Luteinizing hormone-releasing hormone (LHRH release, which serves as the primary drive to the hypothalamic-pituitary gonadal axis, is controlled by many neuromediators. Serotonin has been implicated in this regulation. However, it is unclear whether the central effect of serotonin on LHRH secretion is exerted directly on LHRH neurosecretory neurons or indirectly via multisynaptic pathways. The present studies were undertaken in order to examine whether LHRH secretion from immortalized LHRH cell lines is directly regulated by serotonin and, if so, to identify the receptor subtype involved. 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), a 5-HT1A/7 receptor agonist, stimulated LHRH release from GT1-1 cells. This effect was blocked by ritanserin, a 5-HT2/7 receptor antagonist, but not by SDZ-216-525, a 5-HT1A antagonist. Basal LHRH release was not affected by the 5-HT2 agonist DOI. Reverse transcription and polymerase chain reaction technique (RT-PCR) was used in order to identify 5-HT1A and 5-HT7 receptor mRNA in immortalized LHRH cell lines. GT1-1 cells express mRNA for the 5-HT7, but not the 5-HT1A receptor subtypes. These results demonstrate a direct stimulatory effect of serotonin on LHRH release via 5-HT7 receptor.
Héry
M
M
Laboratoire de Neuroendocrinologie Expérimentale, INSERM U297, Faculté de Médecine Nord, Institut Fédératif Jean Roche, Marseille, France. herym@jean-roche.univ-mrs.fr
François-Bellan
A M
AM
Héry
F
F
Deprez
P
P
Becquet
D
D
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology; D000818:Animals; D002461:Cell Line, Transformed; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007211:Indoles / Q000494:pharmacology; D051379:Mice; D008822:Mice, Transgenic; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis; D012194:RNA-Directed DNA Polymerase; D011985:Receptors, Serotonin / Q000235:genetics / Q000502:physiology*; D016713:Ritanserin / Q000494:pharmacology; D012701:Serotonin / Q000235:genetics / Q000494:pharmacology*; D012702:Serotonin Antagonists / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D013844:Thiazoles / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D007211:Indoles; D012333:RNA, Messenger; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; D013844:Thiazoles; C080378:SDZ 216-525; D016713:Ritanserin; D012701:Serotonin; D007987:Gonadotropin-Releasing Hormone; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D012194:RNA-Directed DNA Polymerase