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, 17[beta]-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 17[alpha]-or 17[beta]-oestradlol, meso- or racemic hexoestrol inhibited the uptake of 17[beta]-oestradiol-H3 by the uterus but not by the diaphragm. The most oestrogenic isomer found was the one most effective in inhibiting uptake. Prior injection of 17[beta]-oestradiol in vivo inhibited the uptake in vitro of 17[beta]-oestradiol-H3. It is concluded that the uptake of oestro?gens by the mouse uterus in vitro is stereospeclfic in the same way as the uptake in vivo.