Hepatocytes isolated from F344 rats were transplanted into the spleens of congenic Nagase analbuminemic rats (NARs). The morphology and function of the transplanted hepatocytes were investigated after 18 months. The hepatocytes had formed nodules that occupied approximately 35% of the area of the splenic parenchyma on microscopic examination. Ultrastructural examination demonstrated that the organelles of the transplanted cells were indistinguishable from those of normal hepatocytes. The serum albumin level in NARs at 18 months after intrasplenic transplantation (HCTx) was about 3.6% of that in normal rats. We confirmed that the hepatocytes in the spleen produced albumin and increased the serum albumin level in NARs with HCTx. The NAR model demonstrates the effect of HCTx and prolonged changes in the morphology of the hepatized spleen.