Influence of age on duodenal brush border membrane and specific activities of brush border membrane enzymes in Wistar rats.

To examine age-related changes in the morphology of intestinal brush border membrane (BBM; microvilli) and specific activities of intestinal BBM enzymes including alkaline phosphatase (ALP), gamma-glutamyl transpeptidase (gamma-GT), and disacchridase, four groups of Wistar rats were sacrificed at 2.5 wk, 5 wk, 5 mon and 23 mon. In an electron microscopic examination, morphologically a less dense BBM structure in the duodenum of rats aged 23 mon was observed than that of rats aged 5 mon. Specific activity of ALP in the duodenum from 5-mon-old rats was significantly higher than from rats aged 2.5 wk and 23 mon. The mucosal tissues from 5-wk-old rats had significantly higher specific activity of gamma-GT than did tissues from the other ages. In sucrase and maltase specific activities, 5-mon-old rats had higher activities of these enzymes than other age groups, especially 2.5-wk- and 23-mon-old rats. There was also a significant effect of site on intestinal BBM enzyme activities in post-weanling rats. Regional gradients of ALP and gamma-GT along the entire small intestine (duodenum > jejunum > ileum) were remarkable. Disaccharidase activities peaked in the jejunum and declined toward both the duodenum and ileum. Taken together the result obtained here suggested that 5-mon-old rats had the most elevated intestinal function. This result also strongly indicated that the structure of the intestinal BBM and development of intestinal BBM enzymes in Wistar rate were markedly influenced by age during the postnatal period.     

Effect of envenomation on enzymes of brain of albino rats

Effects of high doses of cobra venom, (150 micrograms/120 +/- 20 g body wt) and viper venom (300 micrograms/120 +/- 20 g body wt) on aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), acetylcholinesterase (ACh) and alkaline phosphatase (ALP) of brain of albino rats were studied. While AST, LDH, ACh and ALP activities increased in both viper and cobra venom treated rats, ALT decreased in both groups compared to control.     

Effect of graded doses of nicotine on ovarian and uterine activities in albino rats

Nicotine (2 and 4 mg/kg body weight, i.p.) administered to albino rats for 20 days decreased the number of healthy follicles and increased the number of regressing follicles in the ovary. Uterine weight, its diameter, thickness of myometrium and endometrium and height of epithelium were reduced. Increase in the ovarian cholesterol level and decrease in glycogen content in nicotine treated rats indicate the inhibition brought in the steroidogenesis which is dependent on pituitary gonadotrophins. Decreased protein content of the ovary and uterus may be due to their retarded growth. Reduced number of estrous cycle with prolonged metaestrus and diestrus also supports the decreased estrogen synthesis responsible for cornification of vaginal smear in nicotine treated rats.     

Effect of static magnetic field on some enzymes activities in rats

The magnetic field of 0.008 T and 0.15 T inductions influence lasting 7 weeks (7 days a week), 1 h daily determines the increase of the activity of cytoplasmatic enzymes (glutamic pyruvic transaminase, glutamic oxalacetic transaminase, lactic dehydrogenase), the decrease of cholinesterase activity and the growth of alkaline phosphatase activity in the plasma of the examined animals. The observed changes were reversible. 2 months after the exposure had been stopped, the tested parameters were back to normal.     

Effects of adding some dietary fibers to a cystine diet on the activities of liver antioxidant enzymes and serum enzymes in rats

This study investigates whether some dietary fibers can the toxicity due to cystine added to the diet. Wistar rats were investigated for the effects of adding pectin, sugar beet fiber or konjac mannan to a cystine diet on the growth rate and on the activities of liver antioxidant enzymes and serum enzymes. The addition of pectin, sugar beet fiber or konjac mannan to the cystine diet resulted in a significant increase in both the food intake and body weight gain. Feeding the cystine diet caused lower activities of total and Cu,Zn-superoxide dismutase, and of catalase in the liver. The addition of pectin to the cystine diet counteracted the activities of the total and Cu,Zn-superoxide dismutase, and of catalase in liver. Of the dietary fibers tested, konjac mannan prevented the elevation of the two enzyme activities in the serum induced by feeding the cystine diet, indicating that this fiber might have the ability to alleviate hepatic damage due to dietary cystine.     

Toxic effects of different concentrations of dimethoate on lysosomal enzymes of female albino rats.

The effect of three different concentrations of dimethoate on the activity of certain lysosomal enzymes, viz. beta-glucuronidase, beta-N-acetylglucosaminidase, cathepsin B and cathepsin D in serum, skin, liver, kidney and spleen and the stability of liver and kidney lysosomes was studied in female albino rats. The activity of beta-glucuronidase, beta-N-acetylglucosaminidase, cathepsin D was found to increase in serum and tissues in higher concentration (2.25 mg/100 g body weight) of dimethoate treated rats. A significant increase in the rate of release of beta-glucuronidase was found in the liver and kidney of higher concentration of dimethoate treated rats compared to controls. The results demonstrate that the activity of lysosomal enzymes increased in higher concentration of dimethoate treated rats than the lower concentration (0.56 mg/100 g body weight) of dimethoate treated rats.     

Heat acclimation causes some alterations in serum enzymes activities in streptozotocin-diabetic rats

The present study investigated the effect of long-term heat acclimation and experimental diabetes on serum activity of transaminases (AST, ALT), ALP, LDH and elastase complex, as well as blood glucose and HbA1c level in Wistar rats. The heat acclimation model was established with the artificial heat chamber (35±1 °C and 30-40% humidity) for a period of 28 days, while the control groups were held on 20±2 °C. Experimental diabetes was induced by single streptozotocine (STZ) injection (55 mg/kg bodyweight) The changes caused by insulin treatment (2 IU/100 g body weight, 14 days, twice daily) in both thermal groups were also investigated.STZ-diabetes leads to significant increase in blood glucose and HbA1c level, AST, ALT and ALP activities in both thermal groups (normothermic and heat acclimated), decrease in LDH activity in normothermic animals and increase in heat-acclimated ones. Treatment with insulin restores the blood glucose, HbA1c and enzymes activities regardless of the previous thermal exposure.Prolonged acclimation of control animals to elevated ambient temperature resulted in significant decrease in blood glucose level, AST, ALT, ALP and LDH activities and non-significant changes in HbA1c. Compared to diabetic rats from room temperature, heat-acclimated diabetic ones have significantly higher blood glucose, AST, ALP and LDH activity, lower HbA1c concentration and no significant changes in ALT. Most of the changes observed in heat-acclimated insulin-treated diabetic rats did not significantly differ compared to those from room temperature.The overall two-way ANOVA analyses showed that diabetic state causes significant changes in the blood glucose, HbA1c, AST, ALT and ALP activity, while heat acclimation causes significant changes only in HbA1c level and AST activity. Both of the factors (diabetic state and heat acclimation) have significant common effects on AST, ALP and LDH activity.     

次声暴露对大鼠脾、肝脏某些酶活性的影响

目的:观察8 Hz,130 dB次声暴露不同时间对大鼠脾、肝脏某些酶活性的影响.方法:35只SD大鼠随机分为5组,即对照组,1周,2周,3周,4周组.每天次声暴露1次,每次2 h.实验后,观察大鼠脾、肝脏组织中MAO,GSH-px,SOD活性和MDA含量的变化.结果:大鼠脾脏MAO活性1周,2周时显著增高(P＜0.01),3周下降,4周时又显著增加(P＜0.05).肝脏组织MAO活性变化不明显(P＞0.05).脾脏组织中GSH-px活性在4周时明显增高(P＜0.05),肝脏组织中GSH-px活性在1周时就有显著性增高(P＜0.05).脾脏SOD活性在1周至4周均有显著性增高(P＜0.05).肝脏组织在实验期变化不明显(P＞0.05).脾脏组织中MDA含量在3周至4周时有显著性增高(P＜0.05).肝脏组织在1至2周时有非常显著的增高(P＜0.01),在3周时下降,到4周时又显著高于对照组(P＜0.05).结论:8Hz,130 dB次声暴露,大鼠脾、肝脏组织活性氧自由基、脂质过氧化物增高,抗氧化能力降低,造成对组织的损伤.     

Lactulose-induced diarrhoea in rats: effects on caecal development and activities of microbial enzymes

The intake of large amounts of lactulose and other non-digestible oligosaccharides can cause diarrhoea in rats and humans. The purpose of our study was to estimate tendency and scope of changes in caecum development, amount and composition of caecal digesta and activity of caecal microbial enzymes under the influence of lactulose-rich diet evoking or not evoking diarrhoea. Male Wistar rats were fed on 8%-lactulose diet for 4 weeks. Feeding with lactulose induced enlargement of the caecum (digesta and wall) compared to the control group. However, the hypertrophy of the caecal wall in rats with diarrhoea was less than in these without that ailment. Dry matter of caecal digesta was significantly decreased in rats with diarrhoea. Diarrhoea lowered concentrations of enzymatic protein and short-chain fatty acids in the caecum, and the activity of bacterial beta-glucuronidase, alpha- and beta-galactosidase, alpha- and beta-glucosidase in caecal digesta, compared to rats without diarrhoea. The ammonia concentration in the caecum was enhanced by diarrhoea symptoms. Occurrence of diarrhoea significantly deteriorated functioning of the caecal ecosystem what in turn limited potential benefits of diet supplementation with lactulose.