insulin therapy had no effect on the survival of rats with D-The effect of high-dose alanine on survival and liver galactosamine (D-gal)-induced acute liver failure. 6 Liver refunction in rats with acute liver failure caused by a legeneration has been found to be controlled and stimulated thal dose of D-galactosamine (D-gal) was studied. Greater by some growth-promoting substances. 7 Hepatocyte growth than 90% of control animals died within 5 days after D- factor has a powerful stimulatory effect on DNA synthesis in gal injection, but alanine significantly decreased mortalprimary cultured hepatocytes and also promotes it in hepaity, even when treatment was started at 12 hours after tectomized rats. 8-10 A significant improvement of survival D-gal injection. Alanyl-glutamine had a slight effect, but after administration of a hepatic stimulatory substance preglucose produced no improvement. There was marked pared from liver homogenates was reported in rats with D- elevation of the plasma aspartate transaminase (AST)
gal-induced fulminant hepatic failure, 11 but some further level, prolongation of the prothrombin time, and a destudies have suggested that these growth factors are present crease of the arterial ketone body ratio (AKBR) and heat high levels as part of the normal response to liver injury patic adenosine triphosphate (ATP) content within 12 and that exogenous supplementation may be clinically usehours after D-gal injection. The AKBR decreased in parless. 12-14 Accordingly, other therapeutic agents or methods allel with the decrease of the hepatic ATP content. These that have the potential to improve liver function and promote parameters were significantly improved in alanineregeneration are required. treated rats at 48 hours after the induction of liver dam-It is well known that clinical and experimental liver disage, which was just before control rats began to die.
eases are accompanied by the alteration of carbohydrate and The hepatic ATP content was significantly greater in amino acid metabolism for energy production and that healanine-treated rats than in the other rats (including patic gluconeogenesis from amino acids is markedly denormal controls), but glucose pretreatment had no efpressed. 15,16 We recently found that administration of high fect. It was also found that the liver labeling index of doses of alanine (Ala) and glutamine (Gln) prevented severe partially hepatectomized rats was significantly elevated fatty deposition in experimental fatty liver caused by ethanol by alanine administration at 3 hours before measureand hydrazine sulfate. 17 We also found that a high concentrament. In conclusion, alanine is effective for the treattion of Ala had a significantly greater cytoprotective effect ment of experimental acute liver failure, probably than other amino acids or glucose and improved the viability caused by promotion of ATP synthesis. Ala may be a of both damaged and normal primary cultured hepatocytes. 18 good candidate for clinical application because of its
In the present study, we examined whether Ala was effective preventive effect on hepatocyte necrosis and its promoin an animal model of severe hepatic damage and found that tive effect on liver regeneration. (HEPATOLOGY 1996; high-dose Ala improved the survival of rats with acute liver 24:1211-1216.) failure induced by a lethal dose of D-gal. We also found that Ala stimulated liver regeneration and increased hepatic The development of an effective treatment for fulminant adenosine triphosphate (ATP) production in rats. acute hepatic failure, a condition with an extremely poor
Methods
prognosis and a high mortality rate, is a major current objective of clinical hepatology. The most appropriate treatment Animals. Male Fischer rats, weighing 170-190 g, and Spragueapart from liver transplantation 1 is to prevent progressive Dawley rats, weighing 120-140 g, (Charles River Japan Co., Atsugi, Japan) were used. All animals received humane care in accordance hepatocyte necrosis and encourage liver regeneration. Adwith the Japanese guidelines for animal experimentation (Japanese ministration of glucagon and insulin therapy was reported Association for Laboratory Animal Science, 1987). The rats were to promote hepatic recovery in patients with alcoholic or fulprovided with a commercial diet (CRF-1; Oriental Yeast Co., Tokyo, minant hepatitis in association with the acceleration of DNA Japan) and water ad libitum and were maintained in an air-condisynthesis. [2][3][4] However, the clinical effect of glucagon and insutioned room (23ะC { 2ะC) with a 12-hour light-dark cycle. Animals lin therapy is not satisfactory, perhaps because the glucagon were acclimatized for a minimum of 1 week before use. receptors on hepatocytes are destroyed in severe hepatic Preparation of Rats With Acute Liver Failure. D-Gal (Sigma damage. 5 Nishiguchi et al. also showed that glucagon and Chemical Co., St. Louis, MO) was dissolved in physiological saline and adjusted to pH 6.8 with 1N NaOH. After fasting for 12 hours, male Fischer rats were administered D-gal intraperitoneally at a dose of 1.4 g/kg. The rats were fasted for 12 hours after D-gal injection Abbreviations: D-gal, D-galactosamine; ATP, adenosine triphosphate; AKBR, arterial but were provided with water containing 10% glucose to maintain ketone body ratio; AST, aspartate transaminase; PCNA, proliferating cell nuclear antigen.
the blood glucose level.