Location of renal ornithine decarboxylase activity

Renal ornithine decarboxylase (ODC) activity was found to be more prevalent in the medulla of the normal rat kidney than in the cortex. When renal ODC activity was stimulated by ethanol, growth hormone, ACTH, or corticosterone, proportional increases were observed in both medulla and cortex. After hypophysectomy, ODC activities fell equally in both areas of the kidney. The administration of cycloheximide, which is known to cause a rebound increase after six hours in overall renal ODC activity, was followed by an increase of medullary ODC activity while cortical activity remained suppressed.