Cell Proliferation Accelerating and Inhibiting Substances in Blood Serum During Pregnancy.

Abstract

Summary1. Two types of factors which affect cell proliferation have been observed in blood serum, one of which accelerates the rate of normal cell proliferation, and the other inhibits the proliferation of normal cells. Normal blood serum contains a predominance of factcrs which accelerate the rate of normal cell proliferation. During pregnancy there is a progressive change in the balance of factors which affect cell proliferation such that the factors which inhibit proliferation of normal cells become predominant.2. The rate of cell proliferation of a cell suspension in vitro of cells obtained from rat embryos and fetuses, at least up to the 15th day of pregnancy, is accelerated by 2-amino-4-hydroxy-7-methyl pteridine and cancer blood serum and inhibited by xanthopterin and normal human blood serum.3. The rate of cell proliferation of a cell suspension in vitro, of cells obtained from rat young at the time of birth, is accelerated by xanthopterin and normal human blood serum and inhibited by 2-amino-4-hy...