Effects of passive immunization against oestradiol on mouse ovum transport

The ability of anti-oestradiol immunoglobulin to withhold oestradiol-17 beta from its target tissue was examined. The total oestradiol-17 beta binding capacity present in in-vitro incubations or injected into mice intravenously was related to the amount of [3H]oestradiol present in the media or intravenously injected into the animals respectively. When the ratio of binding capacity to [3H]oestradiol was above 74:1, [3H]oestradiol was successfully withheld from uterine tissue in vitro and in vivo. Injecting anti-oestradiol immunoglobulin into mice before administration of a tube-locking dose of oestradiol-17 beta ensured normal passage of ova through the oviduct. Daily administration of anti-oestradiol immunoglobulin to PMSG-hCG stimulated mice (starting 72 h before hCG injection) induced retention of ova for at least 2 days beyond the time when all ova had left the oviducts of control animals. The binding capacity: oestradiol-17 beta concentration ratios of sera from these animals were greater than 250:1 throughout the experimental period. Non-specific immunoglobulin had no such effects, indicating the specificity of the anti-oestradiol immunoglobulin response.