Effect of thyroid hormone on slow calcium channel function in cultured chick ventricular cells.

ABSTRACT: The hyperthyroid state is associated with increased myocardial contractility. To clarify responsible mechanisms, we examined the effects of thyroid hormone on slow Ca channels, beta-adrenergic receptors, transsarcolemmal 45Ca flux and cytosolic free calcium in cultured chick ventricular cells. Compared with cells grown without triiodothyronine (T3), cells grown in 10 nM T3 possessed 67% (P less than 0.05) more dihydropyridine 3H-PN200-110 binding sites, 24% (P less than 0.05) more beta-adrenergic antagonist 3H-CGP12177 binding sites, a 57% (P less than 0.05) greater nifedipine-sensitive initial 45Ca uptake rate, and a 31% (P less than 0.05) greater nifedipine-sensitive 45Ca uptake rate in response to BAY k 8644. Time-averaged mean intracellular free Ca concentration ([Ca]i) measured with f

SUBMITTER: Kim D 

PROVIDER: S-EPMC442205 | biostudies-literature | 1987 Jul

REPOSITORIES: biostudies-literature