EXPRESSION OF PROGESTERONE-BINDING PROTEIN IN NORMAL AND NEOPLASTIC HUMAN ADRENALS
The Japanese Journal of Urology
ヒト正常副腎および副腎腫瘍組織における progesterone 結合蛋白の発現
Specific progesterone-binding protein (P4-BP) is demonstrated in adrenocortical nuclei of the guinea pig, but, not in nuclei of other animals. We tried to demonstrate the progesterone-binding activity in nuclei of human normal adrenals and adrenal tumors. Normal adrenals were obtained from six patients with renal cell carcinomas undergoing radical nephrectomy. Seven adrenocortical adenomas were obtained: five tumors from patients with Cushing's syndrome, one tumor from nonfunctioning adenoma,
... d one from aldosteronoma. Nuclei were purified from the tissues, and progesterone binding assay was performed. We could not demonstrated progesterone-binding activity in nuclei of six normal human adrenals. However, we demonstrated progesterone-binding activity in nuclei purified from human adrenocortical adenomas associated with Cushing's syndrome. Saturation analysis revealed a Kd of 13. 85 + 1. 99 nM (mean + SD, n=5) and a binding capacity of 1. 95 f 0. 37 pmol/mg DNA (mean f SD, n=5). A Kd of progestrerone-binding activity in human adrenocortical adenoma was similar to that of guinea pig P4-BP, and a binding capacity was about one-fifteenth of guinea pig P4-BP. However, nuclei purified from a non-functioning adrenocortical adenoma and an aldosteronoma failed to demonstrate progesterone-binding activity. The binding activity was specific for progesterone. 5a-pregnane-3, 20dione was a modest competitor, while, 17/3-estradiol, testosterone, cortisol, and other related steroids were poor competitors. Thus the progesterone-binding activity in human adrenals was similar to guinea pig P4-BP in the affinity and specificity of binding. Furthermore, we demonstrated [3H] progesterone bound to nuclei from normal human adrenals, as well as, from adrenocortical adenomas associated with Cushing's syndrome by means of thin layer chromatography. It is possible that the progesterone-binding activity is too low to be detected by the classical steroid binding assay.