We have examined the effects of sodium (Na+) salts on rat liver adenylate cyclase. Increasing concentrations of Na+ salts produced biphasic stimulation and inhibition of adenylate cyclase and potentiated enzyme activation by GTP and its hydrolysis resistant analog 5'-guanylyl imidodiphosphate. Salt effects were temperature dependent, of rapid onset, and specific for the Na+ cation though also partly dependent on the accompanying anion. Sodium salt stimulation of adenylate cyclase and enhancement of GTP activation were attenuated by agents (pertussis toxin and N-ethylmaleimide) which inactivate the inhibitory guanine nucleotide-binding regulatory component (G(i)) of adenylate cyclase. Cholera toxin, which activates the stimulatory guanine nucleotide-binding regulatory component (G(s)) of adenylate cyclase and thereby increases enzyme activity, augmented the inhibitory phase of Na+ salt action. These results suggest that the stimulatory and inhibitory effects of Na+ salts may be due, respectively, to inhibition of G(i) and G(s) modulation of adenylate cyclase.
|Original language||English (US)|
|Number of pages||17|
|Journal||Second Messengers and Phosphoproteins|
|State||Published - Dec 1 1988|
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