Serotonin stimulates GnRH secretion through the c-Src-PLC gamma1 pathway in GT1-7 hypothalamic cells.
Serotonin is a neurotransmitter that alters the hypothalamic-pituitary-adrenal axis. To date, however, the molecular mechanisms underlying the role of serotonin in hormone secretion have remained largely unclear. In this study, we report that serotonin activates phospholipase C (PLC) gamma1 in an Src-dependent manner in hypothalamic GT1-7 cells, and that pretreatment with either 4-amino-5-(4-chlorophenyl)-7-(t-butyl) pyrazole [3, 4-d] pyrimidine, an Src-kinase inhibitor, or U73122, a PLC inhibitor, attenuates the serotonin-induced increase in calcium levels. Also, PLC gamma1 binds to c-Src through the Src-homology (SH) 223 domain upon serotonin treatment. Moreover, calcium increase is alleviated in the cells transientlyexpressing SH223 domain-deleted PLC gamma1 or lipase inactive mutant PLC gamma1, as compared with cells transfected with wild-type PLC gamma1. Furthermore, the inhibition of the activities of either PLC or Src results in a significant diminution of the serotonin-induced release of gonadotropin-releasing hormone (GnRH). In addition, the results of our small-interfering RNA experiment confirm that endogenous PLC gamma1 is a prerequisite for serotonin-mediated signaling pathways. Taken together, our findings demonstrate that serotonin stimulates the release of GnRH through the Src-PLC gamma1 pathway, via the modulation of intracellular calcium levels.
Kim
Hyeon Soo
HS
Division of Molecular and Life Science, Department of Life Science, Pohang University of Science and Technology, San31 Hyoja-Dong Nam-Gu Pohang, Kyungbuk 790-784, South Korea.
Yumkham
Sanatombi
S
Choi
Jang Hyun
JH
Son
Gi Hoon
GH
Kim
Kyungjin
K
Ryu
Sung Ho
SH
Suh
Pann-Ghill
PG
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D004789:Enzyme Activation; D004963:Estrenes / Q000494:pharmacology; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism*; D047468:Immunoprecipitation; D008049:Lipase / Q000378:metabolism; D051966:Phospholipase C gamma / Q000235:genetics / Q000378:metabolism*; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000378:metabolism*; D011743:Pyrimidines / Q000494:pharmacology; D011760:Pyrrolidinones / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000494:pharmacology; D012701:Serotonin / Q000494:pharmacology*; D015398:Signal Transduction / Q000502:physiology*; D014162:Transfection / Q000379:methods; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors; D019061:src-Family Kinases / Q000037:antagonists & inhibitors
C412373:AG 1879; D004963:Estrenes; D011743:Pyrimidines; D011760:Pyrrolidinones; D034741:RNA, Small Interfering; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D012701:Serotonin; D007987:Gonadotropin-Releasing Hormone; D016392:Proto-Oncogene Proteins pp60(c-src); D019061:src-Family Kinases; D008049:Lipase; D010738:Type C Phospholipases; D051966:Phospholipase C gamma; D002118:Calcium