The presence of LHRH-like receptors in Dunning R3327H prostate tumors.

Quantitative analyses of LH-RH-like membrane receptors were performed in five tumors from the transplantable Dunning R3372H rat prostatic adenocarcinoma. The binding of D-Trp6-LH-RH, an agonist of LH-RH, was observed in all 5 tumors. The antagonist [Ac-Dp-Cl-Phe1,2,D-Trp3,D-Lys6, D-Ala10]-LH-RH was bound to 4 tumors. The apparent equilibrium dissociation constant (Kd) for D-Trp6-LH-RH receptor was from 2.6-3.9 x 10(-10) M. The apparent equilibrium Bmax values (maximum number of binding sites) were from 17.2-86.0 fmol/mg membrane protein for D-Trp6-LH-RH receptor. The Kd for the antagonist was from 2.4-2.7 x 10(-10) M and the Bmax values were from 35.5-66.0 fmol/mg membrane protein. Similar binding studies performed in 6 normal rat prostates showed no binding capacities.