Islet graft-induced changes of beta-hydroxybutyrate dehydrogenase and glucose-6-phosphatase activity in liver cells of diabetic recipient rats

It is known that the liver is a favourable site for implantation of pancrea tic islets since the grafted islets remain metabolically intact and provide long-term normoglycemia in diabetic animals. However, the long-term effect s exerted by the grafted tissue on the host organ are not well defined. We therefore investigated by light and electron microscopy the effects of syng eneic islets on the host organ after intraportal transplantation into the l iver of streptozotocin (STZ)-induced diabetic LEW.1W rats. In addition, tis sue sections of graft-bearing liver were stained by enzyme histochemical me thods for P-hydroxybutyrate dehydrogenase (HBDH) and glucose-6-phosphatase (G6Pase). At 12 weeks after transplantation, the changes seen in the hepato cytes surrounding the grafted islets were hyperproliferation and accumulati on of glycogen. Hepatocytes adjacent to the implanted islets displayed incr eased HBDH activity, whereas G6Pase activity was variable, either decreased or increased. Increased HBDH activity was also observed in the periportal region and in liver cells extending to the central veins. The results demon strate that intraportal islet grafts, in addition to normalizing glucose ho meostasis, exert remarkable effects on the liver parenchyma of experimental ly diabetic recipient rats.