Primary culture of rat mammary epithelial cells. II. Cytotoxic effect and metabolism of 7,12-dimethyl- Cancer and Speciation 107 benz[a]anthracene and N-nitroso-N- methylurea. J Natl Cancer Inst 61:773–777

ABSTRACT-Methods for the primary culture of rat mammary epithelial cells and the response of these cells to various hormones and culture parameters are described. In addition, the techniques for subsequent retransplantatlon of cultured cells Into cleared fat pads of Isogenic hosts as a test for normalcy 01 cultured tissue are detailed. A characteristic and reproducible course of the culture was followed for 2 weeks, after which rat mammary epithelial cells ceased to proliferate and were eventu-ally overgrown by flbroblast-lIke cells. During the initial 2 weeks in culture, mammary cells and contaminating flbroblast-like cells were responsive to polypeptide and steroid hormones and the percentage of prOliferating mammary cells could be enhanced with insulin, prolactin, estradiol, progesterone, and hydrocorti-sone.-J Natl Cancer Inst 61: 765-771, 1978. Most current cell culture systems used to stud