Detection of norepinephrine distribution in rats with adrenal medulla autotransplants using 125I-meta-iodobenzyl guanidine.

The viability of autologous adrenal medullary transplants was evaluated using 125I-meta-iodobenzyl guanidine (MIBG), an adrenal medullary scanning agent. Bilateral cavities in the caudate nuclei were made stereotaxically in Wistar rats. One week later, the left adrenal medulla was resected by microsurgery, followed by reoperation of the cranium and implantation of a 0.5-1.0 mm diameter fragment of the adrenal medulla into the right caudate nucleus. Six weeks after the second operation, MIBG was administered intravenously. Specimens from both cerebral hemispheres, from the right adrenal medulla and blood were analysed by radioactivity counting. The radioactivity present in the blood of the transplanted group of 11.40 +/- 2.35 cpm mg-1 (mean +/- S.E.M.) was significantly higher than in the control group of 4.97 +/- 1.16 cpm mg-1 (P < 0.05). Radioactivity present in the right hemisphere of the transplanted group was 0.66 +/- 0.03 cpm mg-1, also significantly higher than in the control group which was 0.47 +/- 0.04 cpm mg-1 (P < 0.01). Autoradiography revealed increased radioactivity in the area of the transplants, which was also confirmed histologically.