Changes in numbers of α1‐ and α2‐adrenergic receptors in the plasma membranes of hepatocytes from female Donryu rats given feed containing 0.06% of the carcinogen 3′‐methyl‐4‐dimethylamino‐azobenzene (3′‐MeDAB), were examined. α1‐Adrenergic receptors, measured in terms of [3H]‐prazosin binding, decreased to half of the control 2 weeks after the start of this diet, then gradually decreased for the next 22 weeks. α2‐Adrenergic receptors, measured in terms of [3H]clonidine binding, transiently increased 3‐fold over the control at 2 weeks. These changes in the early period of the 3′‐MeDAB diet intake may be related to hepatocarcinogenesis. Copyright © 1990, Wiley Blackwell. All rights reserved