[Evidence for and assay of a chorionic gonadotropin in the rat (rCG)].

A sensitive radioreceptorassay for human and animal gonadotropins made it possible to demonstrate and quantitate a Rat chorionic gonadotropin (rCG) in placental extracts and amniotic fluid. rCG appears as soon as day 8 and concentration is maximum at day 13 of gestation. This hormone might be the major ovarian stimulatory factor during mid gestation period.