title: Response of C-6 glioma to isoproterenol and papaverine in vivo depends on beta-adrenergic receptor density.
abstract: Rat C-6 glioma serves as an experimental model for human glioma. C-6 glioma cells carried to high culture passages in medium containing 10% fetal bovine serum when injected in vivo are unresponsive to treatment with the beta-adrenergic agonist isoproterenol and the phosphodiesterase inhibitor papaverine. When C-6 glioma cells are kept in culture in serum-containing medium, beta-adrenergic receptor density falls and, concomitantly, ability to accumulate cyclic adenosine monophosphate in response to stimulation with catecholamines declines. Responsiveness to treatment in vivo with a beta-adrenergic agonist was restored when C-6 glioma cells were cultured in serum-free defined medium prior to systemic injection into rats. Culturing of C-6 glioma cells in serum-free medium significantly increases the number of beta-adrenergic receptors when compared with C-6 glioma cells grown in serum-containing medium.
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D005910:Glioma / Q000032:analysis / Q000188:drug therapy* / Q000473:pathology; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000627:therapeutic use*; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000188:drug therapy; D010208:Papaverine / Q000627:therapeutic use*; D051381:Rats; D011920:Rats, Inbred WF; D011943:Receptors, Adrenergic, beta / Q000032:analysis*
chemical_list: D011943:Receptors, Adrenergic, beta; D010208:Papaverine; D007545:Isoproterenol