Differential down-regulation of beta 1- and beta 2-adrenergic receptor mRNA in C6 glioma cells.
C6 glioma cells possess both beta 1- and beta 2-adrenergic receptors. In response to exposure to isoproterenol, these cells down-regulated the mRNA for both beta 1- and beta 2-adrenergic receptors in a manner that indicates an independent regulatory mechanism for each subtype. In particular, the mRNA species for the beta 1-adrenergic receptor initially increased two-fold during the first hour of exposure before decreasing to 40% of initial levels at 4 hours after exposure. In contrast, the beta 2 mRNA species decreased rapidly and monotonically to 20% of initial levels by 2 hours. The unique response to isoproterenol of each subtype was blocked by the appropriate subtype-specific antagonists, betaxolol and ICI 118,551. In addition, beta-adrenergic receptor mRNA down-regulation was observed in association with contact inhibition, suggesting that events other than receptor occupancy can regulate beta-adrenergic receptor mRNA levels.
Hough
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Unit of Molecular Neurobiology, National Institute of Mental Health, Bethesda, MD 20892.
Chuang
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DM
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D015784:Betaxolol / Q000494:pharmacology; D002455:Cell Division; D015536:Down-Regulation; D005910:Glioma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D007545:Isoproterenol / Q000494:pharmacology; D011412:Propanolamines / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism*; D012334:RNA, Neoplasm / Q000378:metabolism*; D051381:Rats; D011943:Receptors, Adrenergic, beta / Q000235:genetics* / Q000378:metabolism; D014407:Tumor Cells, Cultured
D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D011943:Receptors, Adrenergic, beta; C026777:ICI 118551; D007545:Isoproterenol; D015784:Betaxolol