Thyrotropin-stimulated electrical excitation and its refractoriness in cultured porcine thyroid cells.
This report demonstrates TSH-stimulated electrical excitation in the thyroid and its refractoriness after exposure to TSH. TSH depolarizes the membrane potentials and causes action potentials. TSH-induced electrical activity is characterized by a latent period, rapid depolarization, action potentials (usually two spikes were observed), and then repolarization to the potential level of the silent phase. This TSH-induced electrical excitation is associated with iodide discharge. Previous exposure to TSH induces refractoriness of electrophysiological excitation and iodide discharge to further TSH stimulation.
D000818:Animals; D002462:Cell Membrane / Q000502:physiology; D002478:Cells, Cultured; D007454:Iodides / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects; D013552:Swine; D013961:Thyroid Gland / Q000502:physiology*; D013972:Thyrotropin / Q000494:pharmacology*; D013997:Time Factors
D007454:Iodides; D013972:Thyrotropin