[Apolipoprotein E immunoreactivity in normal and abnormal adrenal tissues].

Immunohistochemical study on localization of apo E in normal and abnormal adrenal tissues was performed using polyclonal anti-human apo E antibodies. In normal adrenal glands, the cortex showed intense staining, in particular, in the zona fasciculata and the zona reticularis, while the medulla showed weak staining. In a case of adrenal hyperplasia, apo E immunoreactivity was equivalent to that in the normal cortex. In adenomas (primary aldosteronism, n = 7; Cushing's syndrome, n = 2; others, n = 2), apo E was stained normally or to some extent weakly in comparison with the normal cortex. Adrenocortical carcinoma showed only faint staining. The results indicate that apo E may relate to the functional activity of adrenal cortex, and suggest that immunohistochemical study for apo E may help to distinguish the malignancy from benign adrenal neoplasms.