Polarized properties of thyroid cells: a study with cultured porcine cells.

In primary culture porcine cells form polarized cell layers. We have designed culture conditions in which we can have access to only one side of the cell layer, either the apical or the basal surface. In addition, using culture chambers with permeable bottom we can have access to either side of the cell layer which separates two compartments. Using these organized systems we have shown that the iodide concentrating mechanism and the TSH-receptor adenyl cyclase complex are localized on the basolateral domain of the thyroid cell plasma membrane. We also demonstrated the existence on the apical surface of an amiloride sensitive sodium uptake. Finally we observed that about 10% of newly synthesized thyroglobulin appears to be secreted directly into the basal compartment, 90% being secreted in the apical compartment.