Expression of gonadotropin-releasing hormone receptor and effect of gonadotropin-releasing hormone analogue on proliferation of cultured gastric smooth muscle cells of rats.
OBJECTIVE
To investigate the expression of gonadotropin-releasing hormone (GnRH) receptor and the effects of GnRH analog (alarelin) on proliferation of cultured gastric smooth muscle cells (GSMC) of rats.


METHODS
Immunohistochemical ABC methods and in situ hybridization methods were used to dectect protein and mRNA expression of GnRH receptor in GSMC, respectively. Techniques of cell culture, OD value of MTT test, measure of (3)H-TdR incorporation, average fluorescent values of proliferating cell nuclear antigen (PCNA) and flow cytometric DNA analysis were used in the experiment.


RESULTS
The cultured GSMC of rats showed immunoreactivity for GnRH receptor; positive staining was located in cytoplasm. GnRH receptor mRNA hybridized signals were also detected in cytoplasm. When alarelin (10(-9), 10(-7), 10(-5) mol/L) was administered into the medium and incubated for 24 h, OD value of MTT, (3)H-TdR incorporation and average fluorescent values of PCNA all decreased significantly as compared with the control group (P<0.05). The maximum inhibitory effect on cell proliferation was achieved a concentration of 10(-5) mol/L and it acted in a dose-dependent manner. Flow cytometric DNA analysis revealed that alarelin could significantly enhance ratio of G(1) phase and decrease ratio of S phase of GSMC of rats (P<0.05). The maximum inhibitory effect on ratio of S phase was at the concentration of 10(-5) mol/L and also acted in a dose-dependent manner.


CONCLUSIONS
Our data suggest that GnRH receptor can be expressed by GSMC of rats. GnRH analogue can directly inhibit proliferation and DNA synthesis of rat GSMC through GnRH receptors.
Chen
Lei
L
Department of Biological Science and Biotechnology, Tsinghua University, Beijing, 100084, China.
He
Hong-Xuan
HX
Sun
Xu-De
XD
Zhao
Jing
J
Liu
Li-Hong
LH
Huang
Wei-Quan
WQ
Zhang
Rong-Qing
RQ
D000818:Animals; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D015870:Gene Expression / Q000187:drug effects; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives*; D008297:Male; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011966:Receptors, LHRH / Q000235:genetics*; D013270:Stomach / Q000166:cytology*; D014316:Tritium
D018809:Proliferating Cell Nuclear Antigen; D011966:Receptors, LHRH; D014316:Tritium; D007987:Gonadotropin-Releasing Hormone