Ultrastructural morphology and evidence of iodide uptake and protein synthesis in normal human thyroid transplants in nude mice.

Normal human thyroid tissue was xenotransplanted to athymic mice. Well preserved structural properties of the transplants were observed at both light and electron microscopical level. Analysis of the soluble proteins in the transplants by polyacrylamide gel electrophoresis showed that the major fractions were the 19S thyroglobulin, the 27S iodoprotein and a larger protein fraction. Protein synthesizing capacity of the transplants, as measured by in vivo 3H-leucine incorporation into the soluble transplants proteins was demonstrated. The observed 3H-leucine incorporation was in the same magnitude as that found in the original donor tissue at the time of transplantation. Four weeks after transplantation a significant 125I-iodide uptake (2.0%) was observed in the transplants. Corresponding value for the host thyroids was 6.6%. The biological half-time of the accumulated 125I-iodide in the transplants was reduced from 97 days to 38 days between 2 and 4 weeks after transplantation. The biological half-time in the host thyroid increased from 27 days to 32 days during the same period. This investigation shows that normal human thyroid tissue can be transplanted to nude mice with preserved tissue organisation and maintained cellular function.