Immortalized hippocampal cells contain functional luteinizing hormone/human chorionic gonadotropin receptors.
We used immortalized HN33p cells as surrogates for hippocampal neurons to investigate the functional importance of luteinizing hormone (LH)/human chorionic gonadotropin (hCG) receptors. The use of various detection techniques demonstrated that HN33p cells contain LH/hCG receptor transcripts and receptor protein that can bind 125I-hCG. Culturing them with highly purified hCG resulted in a significant, although modest, dose-and time-dependent and hormone specific increase in steady state 5-lipoxygenase (5-LO) mRNA and protein levels. The studies on signaling revealed that treatment of HN33p cells with hCG resulted in a robust dose- and a time-dependent significant increase in media cyclic AMP levels. In addition, treatment with a protein kinase (PK)A inhibitor, isoquinolinesulfonamide (H-89), but not with a PKC inhibitor, bisindolylmaleimide (Bis), prevented hCG from increasing the 5-LO protein levels. Pretreatment of HN33p cells for 48 hrs with 2 microM antisense, but not sense, phosphorothioate oligodeoxy-nucleotides (ODN) synthesized from mouse LH/hCG receptor sequence resulted in a dramatic decrease in LH/hCG receptor protein levels. In the antisense, but not in sense, ODN-treated cells, hCG was unable to increase cyclic AMP and 5-LO protein levels, suggesting that receptors are required for hCG to work in HN33p cells.
Zhang
W
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Department of Obstetrics and Gyncecology, University of Louisville Health Sciences Center, KY 40292, USA.
Lei
Z M
ZM
Rao
C V
CV
D000818:Animals; D001094:Arachidonate 5-Lipoxygenase / Q000378:metabolism; D002461:Cell Line, Transformed; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D007546:Isoquinolines / Q000494:pharmacology; D016859:Lipoxygenase Inhibitors; D008301:Maleimides / Q000494:pharmacology; D051379:Mice; D020319:Oligodeoxyribonucleotides, Antisense / Q000494:pharmacology; D011974:Receptors, LH / Q000378:metabolism*; D015398:Signal Transduction; D013449:Sulfonamides; D013873:Thionucleotides / Q000494:pharmacology; D013997:Time Factors
D006063:Chorionic Gonadotropin; D004791:Enzyme Inhibitors; D007211:Indoles; D007546:Isoquinolines; D016859:Lipoxygenase Inhibitors; D008301:Maleimides; D020319:Oligodeoxyribonucleotides, Antisense; D011974:Receptors, LH; D013449:Sulfonamides; D013873:Thionucleotides; D000242:Cyclic AMP; D001094:Arachidonate 5-Lipoxygenase; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide; C088060:bisindolylmaleimide