Expression of feeding-related peptide receptors mRNA in GT1-7 cell line and roles of leptin and orexins in control of GnRH secretion.
OBJECTIVE
To investigate the expression of feeding-related peptide receptors mRNA in GT1-7 cell line and roles of leptin and orexins in the control of GnRH secretion.


METHODS
Receptors of bombesin3, cholecystokinin (CCK)-A, CCK-B, glucagon-like peptide (GLP)1, melanin-concentrating hormone (MCH)1, orexin1, orexin2, neuromedin-B, neuropeptide Y (NPY)1 and NPY5, neurotensin (NT)1, NT2, NT3, and leptin receptor long form mRNA in GT1-7 cells were detected by reversed transcriptase-polymerase chain reaction. GT1-7 cells were treated with leptin, orexin A and orexin B at a cohort of concentrations for different lengths of time, and GnRH in medium was determined by radioimmunoassay (RIA).


RESULTS
Receptors of bombesin 3, CCK-B, GLP1, MCH1, orexin1, neuromedin-B, NPY1, NPY5, NT1, NT3, and leptin receptor long form mRNA were expressed in GT1-7 cells, of which, receptors of GLP1, neuromedin-B, NPY1, and NT3 were highly expressed. No amplified fragments of orexin2, NT2, and CCK-A receptor cDNA were generated with GT1-7 RNA, indicating that the GT1-7 cells did not express mRNA of them. Leptin induced a significant stimulation of GnRH release, the results being most significant at 0.1 nmol/L for 15 min. In contrast to other studies in hypothalamic explants, neither orexin A nor orexin B affected basal GnRH secretion over a wide range of concentrations ranging from 1 nmol/L to 500 nmol/Lat 15, 30, and 60 min.


CONCLUSIONS
Feeding and reproductive function are closely linked. Many orexigenic and anorexigenic signals may control feeding behavior as well as alter GnRH secretion through their receptors on GnRH neurons.
Yang
Ying
Y
Rui-jin Hospital Affiliated to Shanghai Second Medical University, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai 200025, China.
Zhou
Li-bin
LB
Liu
Shang-quan
SQ
Tang
Jing-feng
JF
Li
Feng-yin
FY
Li
Rong-ying
RY
Song
Huai-dong
HD
Chen
Ming-dao
MD
D000818:Animals; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D004435:Eating / Q000235:genetics; D015870:Gene Expression; D000067757:Glucagon-Like Peptide-1 Receptor; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins / Q000494:pharmacology; D020738:Leptin / Q000494:pharmacology*; D009479:Neuropeptides / Q000494:pharmacology*; D064446:Orexin Receptors; D000068797:Orexins; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D011863:Radioimmunoassay; D043887:Receptor, Cholecystokinin B / Q000235:genetics; D018004:Receptors, Bombesin / Q000235:genetics; D011956:Receptors, Cell Surface / Q000235:genetics; D043562:Receptors, G-Protein-Coupled; D018027:Receptors, Glucagon / Q000235:genetics; D054411:Receptors, Leptin; D018013:Receptors, Neuropeptide / Q000235:genetics; D017476:Receptors, Neuropeptide Y / Q000235:genetics; D018028:Receptors, Neurotensin / Q000235:genetics; D018000:Receptors, Peptide / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
D000067757:Glucagon-Like Peptide-1 Receptor; D047908:Intracellular Signaling Peptides and Proteins; D020738:Leptin; D009479:Neuropeptides; D064446:Orexin Receptors; D000068797:Orexins; D012333:RNA, Messenger; D043887:Receptor, Cholecystokinin B; D018004:Receptors, Bombesin; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D018027:Receptors, Glucagon; D054411:Receptors, Leptin; D018013:Receptors, Neuropeptide; D017476:Receptors, Neuropeptide Y; D018028:Receptors, Neurotensin; D018000:Receptors, Peptide; C107120:bombesin receptor subtype 3; D007987:Gonadotropin-Releasing Hormone