Endothelin receptors in rat adrenal gland visualized by quantitative autoradiography

1. The radioligand [125I]-endothelin was used to map receptors for endothelin in rat adrenal gland using in vitro autoradiography and computerized densitometry. 2. In the adrenal, a high density of binding was found in the adrenal medulla (binding affinity constant 0.18 +/- 0.11 X 10(9)M-1) and zona glomerulosa (binding affinity constant 0.18 +/- 0.07 X 10(9)M-1). Binding was low to undetectable in the zona fasciculata and zona reticularis. Unrelated peptides did not displace endothelin. 3. These results provide evidence of endothelin receptor distribution in adrenal gland and suggest that endothelin might exert multiple actions in the adrenal gland on catecholamine and aldosterone biosynthesis and secretion.