THE EFFECT OF OESTRIN INJECTIONS UPON THE DEVELOPING OVA OF MICE AND RABBITS

Publisher Website
Google Scholar
Abstract
Daily injections of estrin begun on the day of mating ordinarily cause the retention of ova in the fallopian tubes (probably by closure of the tubo-ovarian junction, possibly by inhibition of the normal ciliary mechanism) in either mice (5 rat units per day) or rabbits (100-150 r.u. per day). All ova, whether they descend into the uterus or remain in the tubes, show definite signs of degeneration by the 4th day after copulation. Hence, the prevention of pregnancy resulting from estrin injections during the early preimplantation period is due (a), to the degeneration of the ova long before they are capable of implantation, and (b) secondarily to the prevention of uterine entry of the blastocysts.