UCLA

An epithelial cell line from pig kidney (LLC-PK1) with properties of proximal tubular cells can be maintained indefinitely in hormone-supplemented serum-free medium. Continuous growth requires the presence of seven factors: transferrin, insulin, selenium, hydrocortisone, triiodothyronine, vasopressin, and cholesterol. The hormone-defined medium (a) supports growth of LLC-PK1 cells at a rate of approaching that observed in serum-supplemented medium; (b) allows vectorial transepithelial salt and fluid transport as measured by hemicyst formation; and (c) influences cell morphology. The vasopressin dependency for growth and morphology can be partially replaced by isobutylmethylxanthine or dibutyryl cyclic AMP. The medium has been used to isolate rabbit proximal tubular kidney epithelial cells free of fibroblasts.