Abstract
The stability of glandular epithelial cells has been investigated utilizing the techniques of cell culture. Embryonic chick thyroid was chosen as a representative cell type and methods were developed for the successful clonal culture of thyroid follicular cells.Thyroid cells were found to be morphologically and functionally stable while undergoing rapid division in both dense (monolayer) and dilute (clonal) cell culture. Differentiated features were retained for a minimum of 32 days of primary clonal culture (approximately 17 generations under clonal conditions). During the culture period, the cells retained their epithelial morphology, retained their cytoplasmic rough endoplasmic reticulum, and continued to produce chromatographically detectable thyroid hormones. Hormone production in culture was a specific thyroid characteristic since control cultures of embryonic heart and liver did not contain the hormones.