A total of 272 serial autopsy cases of the aged was examined for the histological studies of the adrenal cortex and measurement of the cortical volume. Focal hyperplasia of the adrenal cortex was classified into 4 groups; nodular hyperplasia, adenomatous hyperplasia, combined hyperplasia and adenoma. The findings were compared to blood pressure level (normotension, labile hypertension and steady hypertension), atherosclerosis of the aorta, medium to small-sized arteries and arterioles of 5 visceral organs (adrenal, kidney, heart, liver and brain). The results obtained were as follows:
1) Focal hyperplasia in adrenal cortex was found in only 23.6% in cases with normotension and in 98.7% in cases with hypertension. Labile hypertension was closely related to nodular hyperplasia (p<0.001) and steady hypertension to adenomatous hyperplasia (p<0.001).
2) Adrenocortical volume was enlarged in group of labile hypertension (3.8cm.3), and in cases with nodular hyperplasia (4.1cm.3), if compared to control group (2.8cm.3).
3) Arterial lesions progressed in parallel with the degree of blood pressure level and its duration, and also became severer as progressing from nodular to adenomatous hyperplasia. Arterial lesions were more closely related with focal hyperplasia than with the blood pressure.
4) Aortic lesions also showed the similar relations with blood pressure and adrenal changes.