Sensitivity of several serum enzymes in detecting carbon tetrachloride-induced liver damage in rats

Studies on vinblastine-induced autophagocytosis in the mouse liver.I. The relation of lysosomal changes to general injurious effects

Intraperitoneal injection of two doses of vinblastine (10 mg/kg and 50 mg/kg) induced a prominent formation of autophagic vacuoles in mouse liver parenchymal cells in 4 h. Clearly recognizable organelles were seen inside these vacuoles. The amount of autophagy was dependent on doses in that autophagosomes almost disappeared within 12 h with the low dose, whereas with the high dose the -ells were filled with residual bodies. Defecation of lysosomal material was ovserved into the sinusoidal lumen 12 h after injection with high dose. The total activities of lysosomal enzymes acid phosphatase, beta-galactosidase, and beta-acetylglucosaminidase did not change in the liver after vinblastine administration. The soluble activities of beta-galactosidase and beta-glucosaminidase were elevated with the high dose 12 h after injection, indicating labilization of the lysosomal membranes. Simultaneously the activities of the three lysosomal enzymes were elevated in the serum. The injurious effect of VBL appeared in light-and electron microscopic levels indicating diffuse necrosis of the liver lobules with the high gose within 12 h, fat accumulation in the cells, accumulation of secretory vesicles containing very low density lipoprotein particles, partial dilatation, vesiculation of endoplasmic reticulum and dilatation of Golgi cisternae. The serum GOT and CPK levels were also elevated

Serum enzyme activities and hepatic triglyceride levels in acute and subacute acetaminophen-treated rats

The dose- and time-related hepatotoxic effects of acetaminophen were investigated in rats using biochemical parameters as indices of hepatotoxicity supplemented by the histopathological examination of the livers. The acute or subacute (twice daily for 7 days) administration of 0.25 g/kg acetaminophen did not produce any noticeable hepatocellular damage. On the other hand, dose-dependent elevations in serum enzyme glutamic-oxaloacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT) and sorbitol dehydrogenase (SDH) activities and hepatic triglyceride (TG) levels were observed following the administration of single doses of 0.5 and lg/kg acetaminophen. Maximal hepatic damage occurred 12-18 h after acute dosing, while the hepatic function returned to control levels by 48-72 h. In contrast with the acutely treated rats, the serum enzyme activities and the hepatic TG levels remained unchanged following 7-day treatment with 0.5 or 1 g/kg acetaminophen. Also, histopathologically the degree of acetaminophen-induced hepatic necrosis was found to be far less extensive in rats given 0.5 and 1 g/kg acetaminophen twice daily for up to one week, as compared with the animals sacrificed 18 h after administering single equivalent doses of this drug. The results suggest that the liver function is reversibly impaired following acetaminophen overdosage, and that the intensity of acetaminophen-induced hepatotoxicity becomes less severe after repeated exposure to this hepatotoxin.

Short-term inhalation toxicity of halogenated hydrocarbons: effects on fasting rats

Male rats, fasted overnight (18 hours), and exposed to various materials in inhalation were more sensitive to the hepatotoxic effects of carbon tetrachloride, 2-chlorobutadiene, 1,1-dibromoethylene, and 1,1-dichloroethylene (DCE). Vinyl chloride monomer and 1,1-difluoroethylene were not acutely hepatotoxic in fed or fasted rats at any concentration tested. Vinyl chloride monomer when administered simultaneously with DCE prevented the injury associated with DCE inhalation in fasted rats. This prevention of injury may be a result of a competitive interaction since the effect was concentration dependent.