Atrophy and hyperplasia in the adrenal medulla.
D000307:Adrenal Gland Diseases / Q000473:pathology; D000313:Adrenal Medulla / Q000166:cytology / Q000473:pathology*; D000367:Age Factors; D000818:Animals; D001284:Atrophy / Q000473:pathology; D002838:Chromaffin System / Q000166:cytology / Q000473:pathology; D006965:Hyperplasia / Q000473:pathology; D008297:Male; D051381:Rats; D013045:Species Specificity