Specific binding of estrogen to nuclei from Japanese quail kidney cells

The binding properties of estrogen to Japanese quail kidney cell nuclei were evaluated by 3H-17 beta-estradiol exchange. Kidney cell nuclei from estrogenized male, as well as laying female quail, had a single class of saturable (0.1-0.2 pmol/mg DNA), high affinity (Kd = 1-2 x 10-10M) nuclear binding sites for 17 beta-estradiol. High affinity estrogen binding sites were not found in kidney cell nuclei from untreated males. Various non-radioactive estrogens (17 beta-estradiol, estrone, estriol and diethylstilbestrol) competed effectively with 3H-17 beta-estradiol for the high affinity binding sites, whereas nonestrogens (testosterone and progesterone) did not complete. It is concluded that the 3H-estradiol binding characteristics of kidney cell nuclei provides strong evidence for a nuclear estrogen receptor in the avian kidney.