Effects of triiodothyronine on resting membrane potential of primary cultured rat submandibular gland cells

The effect of triiodothyronine (T₃) on the resting membrane potential was measured in primary cultured rat submandibular gland cells. The resting membrane potential was 29.5 ± 0.71 mV. The hormone T₃, at concentrations of 10^-9 M or greater, hyperpolarized the cells 5.8 mV (p < 0.05). Hyperpolarization was complete within 24 hours. Ouabain (1 mM) depolarized the cells 5.9 mV. Cells exposed to T₃ and ouabain had the same membrane potential as cells treated with ouabain alone. These data suggest that the hyper-polarization observed can be, in part, attributed to triiodothyronine-induced synthesis of (Na-K)-adenosine triphosphatase.