OESTROGEN BINDING SITES IN THE CHICKEN OVIDUCT SIMILAR TO THOSE OF THE MOUSE UTERUS

ABSTRACT Surviving oviducts and slices of the gizzard of 7–10 day old chickens were incubated at 37° C in a saline medium which contained tritium-labelled 17β-oestradiol. The oviducts took up more 17β-oestradiol than the slices of the gizzard. After washing the oviducts retained 10–20 times more 17β-oestradiol than the gizzard on a wet weight basis. The preferential uptake of 17β-oestradiol in the oviduct was reduced by dilution with unlabelled 17β-oestradiol and by several non-steroidal oestrogens. The optical isomers of the free phenol corresponding to Fenocyclin® and the stereoisomers of hexoestrol produced a quantitatively different inhibition of the uptake of 17β-oestradiol in the oviduct: the more oviductotrophic the isomer, the more potent was the inhibition of the uptake. Progesterone or testosterone did not inhibit the uptake in the oviduct. No hormone tested affected the residual concentration of 17β-oestradiol in the gizzard. A sulphydryl inhibitor, N-ethylmaleimide, inhibited the uptake and retention of 17β-oestradiol in the oviduct but not in the gizzard. These findings show that in vitro the oviduct takes up oestrogens in a very specific way. This was previously found to be the case with the mammalian uterus. A comparison between the present data on the chicken oviduct with those of the mammalian uterus reveals many similarities.