Demonstration of membrane-bound receptors by means of autoradiography

The binding sites of membrane-bound receptors such as insulin, acetyl choline, concanavaline A (Con A) are clearly demonstrated with a radioactive isotope (hot RI) incubation after light fixation. This type of autoradiography (ARG) visualizes the correct binding sites with good morphological characteristics. For steroid hormones such as estrogen including vitamine D₃, the genomic receptor sites cannot be demonstrated with such samples except the essential specific strong binding affinity in the special granules of eosinophilic leucocytes. We demonstrated the binding sites of ¹²⁵I-insulin in liver, red blood cells, and heart muscle; of ¹²⁵I-α-bungarotoxin (bungarotoxin) in rat intercostal muscle motor end-plate, cerebellum, and cerebrum; of ¹²⁵I- or ³H-Con A receptors on the surface of human red blood cells; and of ³H-estradiol or ³H-moxestrol in the special granules of eosinophilic leucocytes in the rat uterus.