RESUMO
Metabolic changes due to chronic renal failure (CRF) were studied in isolated liver cells. In 14 CRF and 14 sham-operated rats, liver cells were isolated by the Berry and Friend method and incubated with various substrates in order to study gluconeogenesis, ureagenesis, ketogenesis, oxygen consumption as well as cytosolic and mitochondrial adenine nucleotide content. CRF rat hepatocytes exhibited a 25% to 45% decrease in gluconeogenesis and ureagenesis (P < 0.05) from all the tested substrates (lactate plus pyruvate, fructose, glycerol, dihydroxyacetone, alanine and glutamine for gluconeogenesis and alanine, glutamine, ammonia and ammonia plus ornithine for ureagenesis), while endogenous rates were unaffected. CRF did not alter ketone body production (acetoacetate and beta-hydroxybutyrate) from oleate or octanoate. In the presence of either oleate, lactate plus pyruvate or ammonia, oxygen uptake as well as cytosolic and mitochondrial total adenine nucleotides were unaffected by CRF, while the mitochondrial ATP/ADP ratio decreased (P < 0.001). Thus, this study of hepatocyte intermediary metabolism during CRF showed an alteration of only gluconeogenesis and ureagenesis pathways. Moreover, the association of normal oxygen uptake together with decreased mitochondrial ATP/ADP ratio suggest a possible increase in hepatocyte ATP demand during uremia.