Use of radioactive microspheres for studies of tubal ovum transport

Experiments were designed to ascertain the fidelity with which radioactive plastic ovum models imitated the time-course of transport of natural ova through the rabbit oviduct. After location of the radioactive microspheres within the intact oviducts, the genital tracts were removed and cleared in benzyl benzoate. Natural ova and ovum surrogates were then visualized in situ. The radioactive microspheres were reasonably good models of transport of natural ova and their sojourn in the oviduct was shortened by progesterone and prolonged by estrogen. Thus they should be useful tools for future studies of own transport under various conditions.