The Effects of Hypophysectomy on the Uptake and Distribution of 3H-Dopamine in the Mouse Adrenal Medulla: An Autoradiographic Study

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Abstract
Effects of hypophysectomy on the cellular localization of radioactivity in the mouse adrenal medulla 15 min-48 h after an injection of 3H-dopamine (3, 4-dihydroxy (ring-G-3H) phenylethylamine hydrochloride) was examined by light microscope autoradiography using glutaraldehyde-fixed and Epon-embedded semi-thin sections. In the control mice, as described previously, 3H-dopamine-derived radioactivity was remarkably higher in the A [epinephrine] cells than in the NA [norepinephrine] cells. This difference was much less distinct in the hypophysectomized mice. Radioactivity in A and NA cells of the hypophysectomized mice was remarkably lower than that of the control mice. In the control mice chromaffin cells near the cortico-medullary junction, A or NA in type, showed larger amounts of radioactivity than those in the center of the medulla. This characteristic distribution of 3H-dopamine-derived radioactivity in the adrenal medulla was obscure in the hypophysectomized mice. All of these hypophysectomy effects were restored by i.p. administrations of ACTH. Adrenal chromaffin cells possess a special uptake system for dopamine, and this uptake system is at work under the control of pituitary ACTH.