title: MA-10 cells transfected with the human lutropin/choriogonadotropin receptor (hLHR): a novel experimental paradigm to study the functional properties of the hLHR.
abstract: MA-10 cells are a clonal strain of mouse Leydig tumor cells that retain many of the properties of Leydig cells including expression of the endogenous lutropin/choriogonadotropin receptor (LHR) and the ability to respond to LH/CG with increased steroidogenesis. Recently we noted a dramatic decrease in expression of the endogenous LHR. Although we do not have an explanation for this decline, we took advantage of it to devise a method that allows for the expression of the recombinant human LHR (hLHR) in a Leydig cell model that is now practically devoid of endogenous LHR. We show that the recombinant hLHR can be expressed at variable densities in MA-10 cells and that it can stimulate cAMP and steroid synthesis as well as activate the inositol phosphate and MAPK cascades. We also show that two naturally occurring mutants of the hLHR associated with Leydig cell hyperplasia and one mutant associated with Leydig cell adenomas are constitutively active when assayed for activation of cAMP, inositol phosphate, progesterone, and MAPK. Our ability to express the hLHR in MA-10 cells (now practically devoid of endogenous LHR) provides a novel paradigm to study the cellular and molecular basis of the functions of the LHR in Leydig cells.
authors.affiliation: Department of Pharmacology, The University of Iowa, Iowa City, Iowa 52242-1109, USA.
authors.forename: Takashi
authors.initials: T
authors.lastname: Hirakawa
authors.forename: Colette
authors.initials: C
authors.lastname: Galet
authors.forename: Mario
authors.initials: M
authors.lastname: Ascoli
mesh_terms: D002460:Cell Line; D006801:Humans; D007985:Leydig Cells / Q000378:metabolism; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D011974:Receptors, LH / Q000235:genetics* / Q000502:physiology*; D015290:Second Messenger Systems / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology; D014162:Transfection
chemical_list: D011974:Receptors, LH; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases