Chromatographic studies on a chorionic gonadotropic activity in the placenta of the rat, mouse and hamster

Acetone-ether extracts of rat, mouse and hamster placentae were fractionated by molecular sieve chromatography on Sephadex G-200. The fractions were tested for immunoreactivity in human chorionic gonadotropin (hCG), hCG-beta-subunit and alpha-subunit radio-immunoassay systems. The elution profiles were compared with those of similar chromatographic studies of a human placental extract and of purified preparations of hCG and its subunits. The results indicate that rodent placentae have a chorionic gonadotropin and that this hormone in the rat, mouse and hamster is structurally similar to hCG with its alpha- and beta-subunits. Extracts of rat and hamster placentae had a gonadotropic activity similar in concentration to that found in normal human placentae at term. Until now, it has been difficult to find an animal model for studying how the production of chorionic gonadotropin is regulated. Our results suggest that rodents may be suitable for such an investigation.