The effects of different types of porto-systemic shunts were judged on vitamin D 25-hydroxylation and proaccelerin synthesis, in 65% hepatectomized dogs. Three types of shunts were performed: termino-lateral porto-caval shunt, mesenterico-caval shunt and spleno-pancreatico-caval shunt. The mesenterico-caval shunt provided better results than the other shunts, probably because of a better preservation of pancreatic hormone supplies to the liver.