Steroid receptors in nonmalignant and malignant kidney tissue of patients with endemic (Balkan) nephropathy.

The presence, affinity, binding capacity, structure and function of receptors for estrogen (ER), progesterone (PR) and glucocorticoid (GR) were investigated in 24 autologous pairs of control and neoplastic kidney tissues of patients with endemic (Balkan) nephropathy. In control tissue, all the three steroid receptors were absent in 20.8% and present in 25.0% of samples, whereas in malignant tissues the percentage of negative samples increased to 37.5% and that of positive ones decreased to 20.8%. Ten patients had identical receptors in both, control and cancer tissues. Due to malignant transformation nine patients lost one or more receptors, while five patients acquired them. Wide ranges of values were obtained when evaluating receptor affinity (Kd) and binding capacity (N). The structure and function of steroid receptors were investigated by determining the sedimentation coefficients (S) of steroid-receptor complexes before and after the activation. The unactivated GR-complex (8 S) was detected in two of control samples only, whereas in the remaining control tissues, as well as in malignant tissues only the activated form (4 S) was found regardless of the activation. PR and ER complexes were detected at 4 S region only. These results show that in endemic nephropathy the structure of steroid receptors may be altered often in both, non malignant and malignant kidney tissue, suggesting that the analysis of receptor structure may be worthwhile for the prediction of the success of eventual hormone therapy.