SPECIFIC UPTAKE OF OESTROGENS BY THE MOUSE UTERUS IN VITRO

ABSTRACT The uterus as well as slices from the diaphragm of immature mice were incubated in vitro with tritium-labelled oestrogens. The active oestrogens, 17β-oestradiol and meso-hexoestrol, were preferentially accumulated by the uterus. The racemic isomer of hexoestrol which is less oestrogenic than the meso-isomer was not preferentially accumulated by the uterus. The addition of non-radioactive 17α- or 17β-oestradiol, meso- or racemic hexoestrol inhibited the uptake of 17β-oestradiol-3H by the uterus but not by the diaphragm. The most oestrogenic isomer found was the one most effective in inhibiting uptake. Prior injection of 17β-oestradiol in vivo inhibited the uptake in vitro of 17β-oestradiol-3H. It is concluded that the uptake of oestrogens by the mouse uterus in vitro is stereospecific in the same way as the uptake in vivo.