Rat ovarian membrane LH/hCG receptor was solubilized in various detergents and reconstituted into proteoliposomes. Upon removal of sodium cholate by active absorption on Bio-Beads SM-2, the functional interaction between receptor and adenylate cyclas¢ was restored. Adenylate ¢yclas¢ was stimulated by hCG, hCG + GTP or GppNHp and NaF. Reconstituted proteoliposomcs bound more 12SI-hCG (528 fmol/mg protein) than membrane-bound receptors (384 fmol/ mg protein). There was no difference, however, in the relative affinity of reconstituted receptor preparations for hCG.