Phosphoethanolamine as a growth factor of a mammary carcinoma cell line of rat.

Abstract

Phosphoethanolamine was identified as the pituitary-derived growth-promoting material that specifically stimulates the rat mammary carcinoma cell line 64-24. The growth characteristics of the 64-24 cell line, which was isolated from a highly hormone-dependent tumor and which retains in culture many characteristics of the original tumor was studied. Previously, crude bovine pituitary extract was shown to contain a significant amount of growth-stimulating activity for these cells, and a growth factor from this extract was purified to homogeneity. The identification of the growth factor as phosphoethanolamine was described. The biological activity of phosphoethanolamine was virtually identical to that of the purified growth factor. A possible role of phosphoethanolamine in the growth of mammary tumor cells as well as of normal mammary epithelial cells and other tissues is discussed.