Accumulation of alprenolol in some polypeptide hormone producing cells and in melanin-containing tissues

The distribution of the beta-adrenergic-receptor blocking drug alprenolol labelled with 3H was studied in mice by whole body autoradiography. The most characteristic feature in the distribution pattern was the accumulation in endocrine cells within the pancreatic islets, the adrnal medulla, the pituitary gland and some cells of the thyroid, presumably representing the parafollicular cells. A hgih accumulation was also observed in melanin-containing tissues.