Follicle formation and iodide metabolism in cultures of human thyroid cells.

Primary cultures were initiated using thyroid tissue obtained at operation from patients with Graves's disease. The in-vitro conditions which permitted the formation of functional follicular structures in both primary cultures and derived sub-cultures were examined. In both situations, culture without the addition of calf serum to the medium resulted in the formation of follicles in response to thyrotrophin. In primary cultures the response to stimulation by exogenous thyrotrophin was variable. However, cells derived from long-term primary monolayers responded to thyrotrophin stimulation in a more predictable manner. In sub-cultures, the ability of cells to concentrate and organify iodide was augmented in a dose-dependent fashion in response to thyrotrophin (0 to 0.2 mu./ml); maximal values of 20 to 80 times those of control cultures being obtained. While follicular structure was maintained at higher hormone concentrations iodide-trapping capacity declined. Similar effects were produced by both low and high purity thyrotrophin and by dibutyryl cyclic AMP. Thyroid cells from two patients with a genetic defect of iodide organification exhibited the same lesion in vitro.