DESENSITIZATION OF BETA-ADRENERGIC STIMULATED ADENYLATE-CYCLASE IN TURKEY ERYTHROCYTES

  • 1 January 1979
    • journal article
    • research article
    • Vol. 5  (5) , 355-366
Abstract
Desensitization of catecholamine stimulated adenylate cyclase (AC) activity is seen in membranes derived from turkey erythrocytes pre-treated with isoproterenol. Membranes from desensitized cells had a loss in maximal catecholamine stimulated AC activity of 104 .+-. 13 (pmol/mg protein per 10'', P < 0.001) compared with controls. When AC was maximally stimulated with NaF or Gpp(NH)p [5''-guanylylimidodiphosphate], the decrements were 84 .+-. 19 (P < 0.005) and 92 .+-. 32 (P < 0.05) pmol/mg protein per 10'', respectively. There was no change in .beta.-adrenergic receptor number in membranes derived from treated cells. While the molecular mechanism accounting for the desensitization is uncertain, there is apparently a lesion distal to the .beta.-adrenergic receptor, possibly involving the nucleotide site or the catalytic subunit of AC, causing the desensitization in the isoproterenol treated cells.