Endothelin Receptor Density in Human Hypertrophic and Non-Hypertrophic Prostate Tissue

Abstract

KONDO, S., MORITA, T. and TASHIMA, Y. Endothelin Receptor Density in Human Hypertrophic and Non-Hypertrophic Prostate Tissue. Tohoku J. Exp. Med., 1994, 172 (4), 381-384-The amount of endothelin receptors in human prostate tissue was measured by radioligand binding techniques using ¹²⁵I-Endothelin -1 and -3 (¹²⁵I-ET-1, -3). Specimens of the non-hypertrophy group were obtained from 6 patients who underwent total cystectomy under the diagnosis of bladder cancer and those of the hypertrophy group from 6 prostatic hypertrophy patients who underwent open prostatectomy. ¹²⁵I-ET-1 bound to the prostate tissue with the KD value of 0.033±0.012nM in the non-hypertrophy group and with the KD value of 0.035±0.012nM in the hypertrophy group. ¹²⁵I-ET-3 bound to the prostate tissue with the KD value of 0.023±0.011nM in the non-hypertrophy group and with the KD value of 0.029±0.016nM in the hypertrophy group. The RD values were not significantly different between the hypertrophy and non-hypertrophy groups. The KD values of ¹²⁵I-ET-1 and ¹²⁵I-ET-3 were similar. The Bmax values (fmol/mg protein) of ¹²⁵I-ET-1 binding to the prostate tissue were 32.18±3.69 to the non-hypertrophy group and 85.66±20.65 to the hypertrophy group. The Bmax values (fmol/mg protein) of ¹²⁵I-ET-3 binding to the prostate tissue were 27.48±5.25 to the non-hypertrophy group and 75.90±13.46 to the hypertrophy group. The Bmax values of both ¹²⁵I-ET-1 and ¹²⁵I-ET-3 were significantly higher in the hypertrophy group than in the non-hypertrophy group. Benign prostatic hypertrophy was found to increase the density of endothelin receptors in human prostate tissue, suggesting that endothelins modulate the pathophysiology of benign prostatic hypertrophy.