Growth of kidney epithelial cells in hormone-supplemented, serum-free medium

Madin Darby canine kidney cells can grow in synthetic medium supplemented with 5 factors - insulin, transferrin, prostaglandin E₁, hydrocortisone and triiodothyronine - as a serum substitute. These 5 factors permit growth for one month in the absence of serum, and a growth rate equivalent to that observed in serum-supplemented medium. Dibutyryl cAMP substitutes for prostaglandin E₁ in the medium, suggesting that increased growth of Maden Darby canine kidney cells results from increased intracellular cAMP. Potential applications of the serum-free medium are discussed. The medium permits the selective growth of primary epithelial cell cultures in the absence of fibroblast overgrowth, and a defined analysis of the mechanisms by which hormones regulate hemicyst formation.