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Specific inhibition by Na + of TSH‐stimulated thyroid cell adenylate cyclase
Author(s) -
Verrier Bernard,
Chambard Marianne,
Mauchamp Jean
Publication year - 1982
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(82)80466-3
Subject(s) - adenylate kinase , cyclase , humanities , medicine , physics , philosophy , receptor
Thyrotropin (TSH), isoproterenol and prostaglandin E: (PGE2) increase acutely intracellular cAMP levels in cultured porcine thyroid cells [1,2] whereas muscarinic agonists decrease this stimulation [3]. Responsiveness to the various stimulators can be modified by culture conditions and by the chronic treatment by the agonists themselves [2,4]. In membrane preparations derived from these cells, TSH, isoproterenol and PGE2 stimulate adenylate cyclase activity [5]. This stimulation is increased (2-3-fold) in the presence of GTP (0.1 mM). The negative effect of carbachol can also be observed in cell-free system provided GTP (0.1 mM) and Na + (70 mM) are present in the assay mixture [6]. Aside from its effect on the negative modulation of adenylate cyclase by ~-adrenergic agonists, carbachol and opiates [7,9,10,14,15], Na + appears to have complex effects on the activity of adenylate cyclase [8-10]. We report here that Na + at low concentrations (0-40 mM) is a potent inhibitor of TSHstimulated adenylate cyclase activity of membrane preparations derived from cultured thyroid cells. In contrast no effect of Na + was observed on isoproterenol or PGE2-stimulated activities.