Characterization of .ALPHA.T3-1 Cells Stably Transfected with Luteininzing Hormone .BETA.-Subunit Complementary Deoxyribonucleic Acid
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Accession number;03A0491633
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| Title;Characterization of .ALPHA.T3-1 Cells Stably Transfected with Luteininzing Hormone .BETA.-Subunit Complementary Deoxyribonucleic Acid |
| Author;
YONEHARA T
(Kumamoto Univ. School Of Medicine, Kumamoto, Jpn)
YAMADA Y
(Kumamoto Univ. School Of Medicine, Kumamoto, Jpn)
KANASAKI H
(Shimane Medical Univ., Izumo, Jpn)
YAMAMOTO H
(Kumamoto Univ. School Of Medicine, Kumamoto, Jpn)
FUKUNAGA K
(Kumamoto Univ. School Of Medicine, Kumamoto, Jpn)
MIYAZAKI K
(Shimane Medical Univ., Izumo, Jpn)
MIYAMOTO E
(Kumamoto Univ. School Of Medicine, Kumamoto, Jpn)
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Journal Title;Endocr J
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Journal Code:F0625A
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ISSN:0918-8959
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VOL.50;NO.3;PAGE.341-354(2003)
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| Figure&Table&Reference;FIG.6, REF.38 |
| Pub. Country;Japan |
| Language;English |
| Abstract;Luteinizing hormone (LH) consists of .ALPHA.- and .BETA.-subunits, and synthesis and secretion of LH are regulated by gonadotropin-releasing hormone (GnRH). In order to examine the molecular mechanisms by which GnRH regulates LH secretion, we transfected .ALPHA.T3-1 cells with rat LH.BETA.-subunit cDNA under the control of a constitutive promoter and established a stable cell line of LH2 cells which secreted LH in response to GnRH. Pulsatile and continuous GnRH pretreatments increased gene expression of the .ALPHA.-subunit and synthesis of LH, and enhanced the LH secretion by brief treatments with GnRH and 56mM KCl. The LH secretions were partially blocked by elimination of extracellular Ca2+. GnRH-induced LH secretion was completely inhibited by calphostin C (a protein kinase C inhibitor) and 1.MU.M wortmannin. In contrast to the GnRH induction, high K+-induced LH secretion was inhibited by KN93, a Ca2+/calmodulin-dependent protein kinase II inhibitor, as well as by 1.MU.M wortmannin. We also confirmed that activation of cAMP-pathway induced LH secretion, but activation of mitogen-activated protein (MAP) kinase pathway was not involved in LH secretion. These results suggest that GnRH directly regulates LH secretion as well as LH.BETA.-subunit synthesis, and that LH2 cells are a useful model for the study of LH secretion induced by several secretagogues. (author abst.) |
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