REINNERVATION OF ALLOGRAFTED PANCREATIC-ISLETS IN THE RAT-LIVER

Rat pancreatic islets were allografted in the liver and were studied m orphologically in order to evaluate possible reinnervation. Islets iso lated from rat pancreas were allotransplanted in the liver of streptoz ocin-induced diabetic rats via the portal vein. Electron microscopy re vealed nerve endings with synaptic vesicles in the transplanted islets 100 days after transplantation, whereas axons in the islets appeared to degenerate several hours after isolation and prior to transplantati on. These findings suggest that the nerve endings observed in the tran splanted islets regenerate from nerves that innervate the recipient's liver. The tissue specimens were also Investigated immunohistochemical ly using antityrosine hydroxylase antibody, and histochemically by the modified Karnovsky and Roots' method for visualizing acetylcholineste rase. Some nerve endings in the transplanted islets reacted positively to antityrosine hydroxylase antibody. Acetylcholinesterase was visual ized in other nerves. These results indicate that norepinephrine- and acetylcholinesterase-containing nerves may reinnervate the transplante d islets.