Endothelin receptors in testosterone-induced prostatic hypertrophy in rats

Endothelin receptors were characterized in rat prostate and potential modification of these receptors was investigated in prostatic hypertrophy induced by testosterone. Both ET(A) and ET(B) endothelin receptor mRNA were detected in rat prostate, whereas binding experiments show the presence of only ET(A) receptors. Testosterone administration produced a 75% increase in prostate weight. Although the density of prostatic endothelin receptors was decreased from 348 +/- 75.0 fmol/mg protein in control rats to 252 +/- 39.9 fmol/mg protein in testosterone-treated animals, the total amount of receptors per prostate was unchanged. The steady-state level of ET(A)- and ET(B)-receptor mRNA was not altered by testosterone treatment. These results suggest that endothelin receptors are not affected in prostatic hypertrophy induced by testosterone.