The absence of desensitization in the beta adrenergic receptors of turkey reticulocytes and erythrocytes and its possible origin

β-adrenergic receptors on turkey erythrocytes and on turkey reticulocytes do not undergo desensitization subsequent to the exposure of the cells to the β-agonist, l-isoproterenol. The increase in the membrane fluidity of the turkey reticulocytes by depleting it of cholesterol does not modify this property of the cells. However, exposure of intact turkey reticulocytes, but not of mature erythrocytes, to dl-propranolol induced a 100% increase in the number of β-adrenergic receptors on the cell surface. This increase is not inhibited by the protein biosynthesis inhibitor cycloheximide. The possible origin of the lack of desensitization in turkey red cells to β-agonists and of the propranolol induced exposure of cryptic receptors is discussed.