Evaluation of ready-to-use liquid reagents for clinical chemistry in laboratory animals

We evaluated the ready-to-use liquid reagents for clinical chemistry (6 tests), to assess their suitability for use in the toxicology laboratory setting. Hitachi 736 automated analyzer was used for the analyses. The evaluation included the following studies: Precision, Linearity, Effects of interference substances such as hemolytic hemoglobin, bilirubin, turbidity to the analytical values and correlation to the solid reagents, which are prepared each time they are needed. The precision and linearity data were within the reagents' specifications. Results of comparison of the liquid reagents and the solid reagents in analyzing plasma samples of rats, dogs and monkeys were generally good except for a bias in results for GOT and GPT, regardless of the animal species tested. It is concluded that these types of liquid reagents can be used in clinical pathology examinations in animal studies.

Enhanced nephrotoxicity of acetaminophen in fructose-induced hypertriglyceridemic rats: effect of partial hepatectomy

Fructose-induced hypertriglyceridemic rats become resistant to hepatotoxicity and susceptible to nephrotoxicity of acetaminophen (APAP). Enhanced susceptibility to APAP nephrotoxicity in fructose-pretreated rats is due, at least in part, to increased renal APAP concentration at the early phase (15 and 30 min after APAP administration). However, the mechanism of an increase in renal APAP concentration is still obscure. The present study was designed to test the hypothesis that a decrease in capacity of hepatic APAP metabolism is responsible for an increase in renal APAP concentration in fructose-pretreated rats. Non-pretreated rats and fructose-pretreated rats (25% fructose in drinking water for 3 weeks) received 70% or 90% partial hepatectomy (PH) or sham operation at 1 hr before APAP administration (600 or 750 mg/kg, i.p.). PH did not potentiate APAP nephrotoxicity and renal APAP concentration, and fructose-pretreated rats showed server renal lesions and greater renal APAP concentration than non-pretreated rats irrespective of PH. The result indicates that an increase in renal APAP concentration in the fructose-pretreated rats has no relation to an alteration in hepatic metabolic capacity of APAP.

Effects of fructose-induced hypertriglyceridemia on hepatorenal toxicity of acetaminophen in rats: role of pharmacokinetics and metabolism of acetaminophen

Fructose-induced hypertriglyceridemic rats become resistant to hepatotoxicity and susceptible to nephrotoxicity of acetaminophen (APAP), as compared with normal ones. The present study was designed to test the hypothesis that alterations in the distribution of APAP and in the intrinsic susceptibility to toxicants are responsible for the alteration in hepatorenal toxicity of APAP in fructose-induced hypertriglyceridemic rats. Following APAP-administration (750 mg/kg, i.p.), fructose-pretreated rats (25% fructose in drinking water for 5 weeks) showed nephrotoxicity of APAP more promptly and more severely than normal ones. Renal APAP-concentrations at the early phase (15 and 30 min. after APAP-administration) were significantly greater in fructose-pretreated rats than those in normal ones. Plasma and hepatic APAP concentrations in fructose-pretreated rats were greater than those in normal ones only at the later phase (plasma; 6 hr, liver; 6 and 12 hr after APAP-administration). There were no significant differences in the APAP-induced depletion of hepatic and renal glutathione and in the basal hepatic and renal cytochrome P-450 contents between these rats. Fructose-pretreated rats were also more susceptible to p-aminophenol (PAP), a nephrotoxic metabolite of APAP, than normal rats. Therefore, enhanced susceptibility to APAP-nephrotoxicity in fructose-pretreated rats may be due, at least in part, to increased renal APAP concentration and increased intrinsic susceptibility to the metabolic nephrotoxicant.

Effects of fructose-induced hypertriglyceridemia on hepatorenal toxicity of acetaminophen in rats. II. Role of enhancement of fructose metabolism and overproduction of triglyceride in the liver and kidney on hepatorenal toxicity of acetaminophen

Fructose-induced hypertriglyceridemic rats are resistant to hepatoxicity and susceptible to nephrotoxicity of acetaminophen (APAP) as compared with normal ones. The present studied were designed to evaluate how fructose-treatment affects the developmental mode of hepatorenal toxicity of APAP. First, following fructose-pretreatment for various durations (1 day, 1 week or 3 weeks), 1-day-fructose-pretreatment induced hypertriglyceridemia and enhancement of APAP-nephrectoxicity simultaneously. However, it took at least 3 weeks for fructose-pretreatment to reduce APAP-hepatotoxicity. Second, following fructose, sucrose or glucose-pretreatment for 3 weeks, fructose-pretreated rats showed marked hypertriglyceridemia and modification of APAP-hepatorenal toxicity. Sucrose-pretreated rats showed less effects than fructose-pretreated rats. Glucose-pretreated rats showed no changes in plasma triglyceride and APAP-hepatorenal toxicity. Third, rats with hypertriglyceridemia induced by olive oil or Triton WR-1339 which did not produce enhanced metabolism and triglyceride-overproduction in the liver and kidney showed no modification of APAP-hepatorenal toxicity. Pretreatment of glycerol which was metabolized in liver and kidney and induced an overproduction of triglyceride resulted in an enhancement of APAP-nephrotoxicity. These results indicate that an enhancement of fructose metabolism and an overproduction of triglyceride in liver and kidney are responsible for the modification of APAP-hepatorenal toxicity in fructose-induced hypertriglyceridemic rats.

A case of the watery diarrhea-hypokalemia-achlorhydria syndrome: successful preoperative treatment of watery diarrhea with a somatostatin analogue

A 35-year-old man presenting with severe watery diarrhea was diagnosed as having the watery diarrhea, hypokalemia and achlorhydria (WDHA) syndrome with the elevation of plasma vasoactive intestinal peptide (VIP) level. Imaging diagnostic techniques revealed a hypervascular tumor at the tail of the pancreas as well as a solitary liver metastasis. During the patient's stay in hospital, he developed acute renal failure probably due to persistent dehydration and severe hypokalemia. Although these complications improved with artificial dialyses, severe watery diarrhea continued, which made it difficult to achieve surgical resection of the tumor. A new long-acting and potent somatostatin analogue, SMS 201-995 (Sandoz Ltd, Basel, Switzerland), was tested and was shown to be effective; after a few hours of subcutaneous injection of this agent, the watery diarrhea disappeared, which in turn improved the patient's hypokalemia, hypercalcemia and metabolic acidosis. Three weeks later, distal pancreatectomy with splenectomy and hepatic lobectomy were successfully performed, and the patient resumed his normal life. The somatostatin analogue has been reported to be useful in the long-term treatment of patients with inoperable WDHA syndrome. The present case demonstrated that short-term administration of this agent is also useful for improving the condition of WDHA patients at the preoperative stage.