Effects of nitrofurans on adrenal cortical tissue in chickens

In chicken adrenal glands, aspartate transaminase (AST) activity is concentrated in the adrenal cortical cells. Administration of a bolus dose of furazolidone (200 mg/kg) to the birds produced a decrease in AST activity in the adrenal glands and a general disorganization in the ultrastructure of the adrenal cortical cells. Many adrenal cortical mitochondria appeared to be moribund, being swollen, without cristae or apparently empty. These effects preceded atrophy of the adrenal cortical tissue, which was most marked in the central part of the adrenal glands. The atrophy was still present after 12 weeks, and it is therefore suggested that nitrofurans may be useful in the treatment of Cushing's disease in other animal species. When furazolidone or furaltadone was given in the diet at therapeutic levels, blebs of an electron-dense substance developed in adrenal cortical mitochondria and AST activity in the adrenal glands was reduced. These effects were found to be reversible, and the treatments did not produce atrophy of the adrenal cortical tissue.