一种已建系的大鼠子宫内膜细胞系及肿瘤中细胞质和细胞核受体的雌激素结合参数。

Estrogen-binding parameters of cytoplasmic and nuclear receptors in an established rat endometrial cell line and tumor.

作者信息

Farookhi R, Sonnenschein C

出版信息

Endocr Res Commun. 1976;3(1):1-19. doi: 10.3109/07435807609057737.

Abstract

We have consistently found receptors for estradiol in both the cytosol and nuclear extracts of a rat endometrial cell line and in transplantable tumors derived from this cell line. The equilibrium dissociation constants (Kd) and the rate constants for the receptor-estradiol interaction in these cells and tumors did not differ significantly from those of the cytosol receptor in the rat uterus. A mean Kd of 3 x 10(-10) M with a rate of association (Ka) of 3 x 10(5) M-1sec-1 and a rate of dissociation (Kd) of 1.5 x 10(-5) sec-1 were obtained for nuclear and cytosol receptors for both tumors and cells. For uterine cytosol, a Kd of 8 x 10(-10) M, ka = 2.8 x 10(5) M-1sec-1 and kd = 1 x 10(-5) sec-1 were obtained. Although no differences were seen in equilibrium and kinetic parameters for estradiol-17beta binding between the nuclear and cytosol receptors of tumors and cells, an apparent difference in the relative affinities of nuclear and cytosol receptors for estrone was detected. This suggests that the binding site in nuclear receptors may have been modified. Implications of this observation with regard to receptor translocation and the mechanism of action of sex hormones are being considered.

摘要

我们一直发现在大鼠子宫内膜细胞系的胞质溶胶和核提取物中，以及源自该细胞系的可移植肿瘤中都存在雌二醇受体。这些细胞和肿瘤中受体 - 雌二醇相互作用的平衡解离常数（Kd）和速率常数与大鼠子宫胞质溶胶受体的相应常数并无显著差异。肿瘤和细胞的核受体及胞质溶胶受体的平均Kd为3×10⁻¹⁰ M，结合速率（Ka）为3×10⁵ M⁻¹秒⁻¹，解离速率（Kd）为1.5×10⁻⁵ 秒⁻¹。对于子宫胞质溶胶，Kd为8×10⁻¹⁰ M，ka = 2.8×10⁵ M⁻¹秒⁻¹，kd = 1×10⁻⁵ 秒⁻¹。尽管肿瘤和细胞的核受体与胞质溶胶受体在雌二醇 - 17β结合的平衡和动力学参数上没有差异，但检测到核受体与胞质溶胶受体对雌酮的相对亲和力存在明显差异。这表明核受体中的结合位点可能已被修饰。正在考虑这一观察结果对受体转位和性激素作用机制的影响。