Activities of digestive enzymes in rats kept on standard or excessive breast feeding and on low-protein diet at once after weaning

Activities of digestive enzymes (maltase, alkaline phosphatase, aminopeptidase M, and glycyl-L-leucine dipeptidase) in small and large intestine, liver, and kidney were studied in rats of different ages kept at the period of lactation under conditions of the standard (8 individuals per litter) and low (3 individuals) number of pups per litter. The low-protein diet for 10 days at once after weaning was found to change the mass of organs and their digestive enzyme activities in all studied rat groups. The revealed changes were more prominent in rats kept under conditions of excessive breast feeding. In adult animals of this group, distribution of the alkaline phosphatase activity along the small intestine differed from that in control rats. The obtained results seem to confirm that any disturbance of the nutrition quality in early ontogenesis leads to disturbance of the «metabolic programming of enzyme systems» of digestive organs.     

东北虎幼体消化系统蛋白水解酶的初步研究

蛋白水解酶在许多生命活动中是必需的物质(Vassalli and Pepper,1994)。蛋白质的酶解修饰(Xuet al.,1999)、细胞迁移、组织再生与修复、消化系统对蛋白质的消化等均与蛋白水解酶有关(Baimbridgeet al.,1992),且蛋白水解酶功能失调会导致许多疾病(Teichertet al.,1989)。东北虎(     

Developmental changes in the activities of prostaglandin synthesizing enzymes in the digestive and immune systems of rat

The developmental changes of prostaglandin (PG) synthesizing enzymes in the digestive system (stomach and small intestine) and the immune system (spleen and thymus) of rats were investigated. In all the digestive organs, the predominant PG produced from PGH2 changed at around 2 weeks after birth to another PG. Further, the predominant activities of PG synthesizing enzymes were different organ by organ in the digestive system. In the case of the immune system, only the activity of PGD2 synthesizing enzyme displayed a significant increase during development and the activities of other PG synthesizing enzymes remained insignificant throughout the development. These results suggest that PGs may play important roles during the development of each organ.     

大鵟消化系统蛋白水解酶种类和活性分析

采用蛋白水解酶复性电泳(G-PAGE)技术对大(Buteo hemilasius)消化系统5种器官腺胃、胰脏、十二指肠、空肠、大肠蛋白水解酶的种类和性质进行了研究,以期为研究野生鸟类的分类地位、系统演化提供基础资料,结果表明,①受pH值的影响和制约,大消化系统蛋白水解酶的活性在碱性、中性与酸性条件下递减;②在酸性条件下,45 ku蛋白水解酶存在于除腺胃外的各受检器官;③pH 7.0时,腺胃、胰脏酶谱相似,均含有683、5、342、0 ku的蛋白水解酶;④pH 8.0时,空肠和十二指肠的蛋白水解酶种类最多、活性最强,分别检出8种和7种蛋白水解酶。总之,pH值对蛋白水解酶的活性有明显的制约作用,46、41ku蛋白水解酶随着pH值的增高而失去活性,为酸性蛋白水解酶,250、2064、5 ku蛋白水解酶随着pH值的增高活性逐渐增强,为碱性蛋白水解酶。十二指肠和空肠的蛋白水解酶种类多、活性强,可能为蛋白质消化的主要场所。     

丽斗蟋翅二型雄虫食物消化能力及消化酶活性比较

【目的】丽斗蟋Velarifictorus ornatus具明显的翅二型现象,为探讨翅型分化对丽斗蟋翅二型雄虫消化能力及中肠内消化酶活性产生的影响,对长翅型与短翅型雄虫食物消化能力及中肠内消化酶活性进行了检测比较。【方法】我们采取重量营养指数测定了羽化后12 d内丽斗蟋两型雄成虫增长量、相对增长率、取食量、食物利用率、近似消化率和食物转化率。为进一步明确丽斗蟋翅二型成虫食物消化能力与中肠内消化酶活性的关系,我们采用4种专用底物测定了中肠内用于分解蛋白质、脂肪和碳水化合物的总蛋白酶、胰蛋白酶、脂肪酶和淀粉酶的活性。【结果】结果表明,丽斗蟋两型雄虫取食量、食物转化率、食物利用率与增长量均无统计差异,但中肠内消化酶活性变化规律不同。成虫羽化后4 d时,长翅型雄虫中肠内总蛋白酶与胰蛋白酶活性显著高于短翅型雄虫,相反,羽化后0 d时,短翅型雄虫中肠内总蛋白酶与胰蛋白酶活性则显著高于长翅型雄虫,而羽化后12 d时,虽然短翅型雄虫总蛋白酶活性高于长翅型雄虫,但胰蛋白酶活性在两型雄虫间并无差异。成虫羽化后0 d时,两型雄虫脂肪酶活性无差异,但无论是羽化后4 或 12 d,长翅型雄虫中肠内脂肪酶活性皆显著大于短翅型雄虫。成虫羽化后4 d时,短翅型雄虫中肠内淀粉酶活性显著高于长翅型雄虫,而羽化后0与12 d时,两型雄虫间无显著差异。【结论】丽斗蟋翅二型雄虫食物消化能力无显著差异,但羽化后不同时间,中肠内消化酶活性存在差异,该差异可能与成虫羽化后不同时期,翅二型雄虫在飞行与繁殖投资中对不同能源物质的需求有关。     

Comparative studies on lipogenic enzyme activities in brown adipose tissue and liver of the rat during starvation-refeeding transition and cold exposure

1. The effect of starvation-refeeding transition and cold exposure on the activity of lipogenic enzymes in brown adipose tissue (BAT) and liver from rats was compared. 2. Starvation caused a decrease of lipogenic enzyme activities in BAT and liver. 3. Refeeding of the animals with a high carbohydrate diet caused an increase of lipogenic enzymes in these tissues. 4. Cold exposure (4 degrees C for 30 days) led to the increase of BAT enzyme activities to the values observed in rats fed a high carbohydrate diet. 5. Under the same conditions the activity of hepatic lipogenic enzymes also increased but never reached the values observed in the liver of rats fed with a high carbohydrate diet. 6. Therefore BAT and liver lipogenic enzymes showed, in general, a similar pattern of variation under identical nutritional conditions, but substantial differences between these two organs occurred as far as the response to cold exposure was concerned. 7. The experiments also revealed that in the control animals BAT displayed a higher lipogenic potential than the liver.     

红螯螯虾胚胎发育期主要消化酶和同工酶的活性变化

采用生物化学方法测定了红螯螯虾(Cherax quadricarinatus)胚胎发育各期主要消化酶(胃蛋白酶、胰蛋白酶、淀粉酶、纤维素酶和脂肪酶)的比活力及主要同工酶(乳酸脱氢酶、苹果酸脱氢酶、葡萄糖-6-磷酸脱氢酶和酯酶)的活力。结果显示,5种消化酶各自表现出不同的变化模式,胃蛋白酶和胰蛋白酶的比活力早期均逐渐上升,到发育后期胃蛋白酶出现快速下降,而胰蛋白酶却仍保持较高水平;淀粉酶比活力呈“V”字型变化趋势,晚期活性较高;纤维素酶和脂肪酶的比活力则均较低。4种同工酶酶谱随胚胎的发育渐趋复杂,酶活性也随之增强。结果表明,消化酶和同工酶活力的高低均受其基因的调控,并随胚胎发育适时表达,为胚胎组织、器官和系统的形成以及未来仔虾的开口摄食提供物质保证。     

Localization of lysosomal and digestive enzymes in cytoplasmic vacuoles in caerulein-pancreatitis

Summary Intracellular localization and enzymatic activities of lysosomal enzymes (cathepsin B,N-acetyl-β-glucosaminidase, and β-glucuronidase) were studied in control rats and after induction of caerulein pancreatitis. In control rats high enzymatic activities were found in the postnuclear 1000g fraction (purified zymogen granules). The corresponding subcellular fraction in pancreatitis animals additionally contained larger secretory vacuoles and autophagosomes and revealed a marked increase in lysosomal enzyme activities. Immunolabelling studies at the ultrastructural level for trypsinogen and cathepsin B demonstrated a colocalization of lysosomal and digestive enzymes in zymogen granules in healthy controls. After induction of pancreatitis immunolabelling still demonstrated a colocalisation of cathepsin B and trypsinogen in secretory granules and newly formed Golgi-derived secretory vacuoles. Concomitantly appearing autophagosomes were, however, only labelled for cathepsin B. It is concluded that segregation of lysosomal and digestive enzymes is incomplete in normal acinar cells resulting in a colocalization in zymogen granules. In pancreatitis colocalization in secretory granules is maintained, whereas only lysosomal enzymes were sufficiently transferred into autophagic vacuoles. No indication for impaired mechanisms of molecular sorting of lysosomal and digestive enzymes in caerulein-induced pancreatitis was found.     

Modulation of gamma-glutamyltranspeptidase activity in rat liver plasma membranes by thyroid hormone

1. In adult male and female rats, liver plasma membrane gamma-glutamyltranspeptidase activities were 16-fold higher in the propylthiouracil (PTU)-induced hypothyroid state than in the control euthyroid state; thyroxine (T4)-replacement resulted in an 80% restoration to control levels. 2. Liver plasma membrane gamma-glutamyltranspeptidase activities were 6.7-fold higher in PTU-induced congenitally hypothyroid rats than in control euthyroid rats; T4-replacement reduced enzyme activities to 37% of control levels. 3. In adult rats, in response to the development and recovery from tri-iodothyronine (T3) excess, liver plasma membrane gamma-glutamyltranspeptidase activities were inversely related to, and out of phase by 12 hr, to the earlier changes in T3. 4. Liver gamma-glutamyltranspeptidase is a thyroid hormone-dependent enzyme.     

Effect of weaning terms and protein deficit in the rat pup nutrition on activities of digestive enzymes

Restriction of protein in nutrition of rat pups weaned at different terms has been found to produce changes in activities of digestive enzymes (maltase, alkaline phosphatase, aminopeptidase M, and glycyl-L-leucine dipeptidase) in the small and large intestine both at once after cessation of nutrition with low-protein diet for 10 days and 4 months later. In adult animals after the earlier or later weaning there are observed not only a decrease or increase of the enzyme activities, but also a different type of distribution of the alkaline phosphatase activity along the small intestine, which is more pronounced in the lately weaned rats. Thus, disturbance of metabolic programming of enzyme systems of the small and large intestine due to a change of quality of nutrition in early ontogenesis depends on terms of weaning of animals.     

Stability of enzymatic indicators of metabolic and neuronal activity in post-ganglionic neurons supplying the urinary tract of aged rats

Aged post-ganglionic neurons supplying the urinary tract exhibit stability in their metabolic and functional status, as demonstrated by quantification of enzyme histochemical reaction products. The major pelvic and thirteenth thoracic (T13) ganglia from 4- and 24-month-old male Wistar rats were incubated under standardized conditions to demonstrate succinate dehydrogenase, NADH-tetrazolium reductase and cytochrome oxidase activities. The amount of reaction product for each enzyme, localized in neuronal perikarya throughout the ganglia, was quantified by microdensitometry. Comparison of mean totals demonstrated stability of all three enzymes with age in both the major pelvic and T13 ganglia and in target organs. Also, the distribution and range of reaction product densities were similar. In both ganglia, the number of NADH-tetrazolium reductase-stained neurons per unit area was reduced in the aged animals. Additionally, nicotinic (DMPP) and muscarinic (McN-A-343) agonists were used to mimic the effects of preganglionic stimulation in the major pelvic ganglia before performing enzyme histochemical reaction. Quantification of these activities demonstrated that the response of aged neurons to preganglionic stimulation was unchanged. These results indicate an overall metabolic stability in post-ganglionic autonomic neurons innervating the urinary tract and in their targets in aged rats. © 1998 Chapman & Hall     

Factors involved in changes in hepatic lipogenesis during development of the rat

1. Changes in the activities of acetyl-CoA carboxylase (EC 6.4.1.2), phosphofructokinase (EC 2.7.1.11), aldolase (EC 4.1.2.13), extramitochondrial aconitate hydratase (EC 4.2.1.3) and NADP-dependent isocitrate dehydrogenase (EC 1.1.1.42) have been measured in the livers of developing rats from late foetal life to maturity. 2. The effect of altering the weaning time on some enzymes associated with lipogenesis has been studied. Weaning rats at 15 days of age instead of 21 days results in an immediate increase in the activity of ;malic' enzyme (EC 1.1.1.40) whereas the activities of glucose 6-phosphate dehydrogenase (EC 1.1.1.49) and ATP citrate lyase (EC 4.1.3.8) did not increase until 4-5 days and acetyl-CoA carboxylase 2-3 days after early weaning. Weaning rats on to an artificial-milk diet led to complete repression of the rise in activity of hepatic enzymes associated with lipogenesis normally found on weaning, except for ;malic' enzyme, which increased in activity after 20 days of age. 3. The effect of intraperitoneal injections of glucagon, cortisol, growth hormone and thyroxine on the same hepatic enzymes has been investigated. Only thyroxine had any effect on enzyme activities and caused a 20-fold increase in ;malic' enzyme activity and a twofold increase in ATP citrate lyase activity. 4. The activities of hepatic glucose 6-phosphate dehydrogenase and ;malic' enzyme are higher in adult female than in adult male rats and it has been shown that this sex difference in enzyme activities is due to both male and female sex hormones. 5. Hepatic malate, citrate, pyruvate, glucose 6-phosphate and phosphoenolpyruvate concentrations have been measured throughout development. 6. The results are discussed in relation to the dietary and hormonal control of hepatic enzyme activities during development.     

Effect of Cestodal Infestation on the Distribution Pattern of Digestive Enzyme Activities along the Small Intestine of the Kittiwake (<Emphasis Type="Italic">Rissa tridactyla</Emphasis>)

Activities of digestive enzymes in the intestine of adult and nestling kittiwakes (Rissa tridactyla) were studied. Glycosidase and protease activities in the three parts of the small intestine (proximal, medial and distal) as well as their total activity were determined, and the glycosidase/protease activity ratio (G/P coefficient) was calculated. Enzyme activities were found to be distributed unevenly along the intestine. In a proximal to distal direction, glycosidase and protease activities decrease in nestlings and increase in adult kittiwakes. In nestlings, protease activity values are several times higher than in adults. G/P coefficient values vary within the range of 0.33–0.92 in adult animals and 0.22–0.41 in nestlings. Infestation with tapeworms Alcataenia larina (Cestoda, Dilepididae) and Tetrabothrius erostris (Cestoda, Tetrabothriidae) leads to reduced digestive enzyme activities in the small intestine of kittiwake nestlings. In adult animals, infestation with T. erostris leads to a reduced and with A. larina to an increased protease activity.     

Effect of thyroxine on some digestive enzymes of the adult male toad,Bufo melanostictus

Thyroxine is known to play an important role during the developmental process of amphibians. The present work is designed on the hypothesis that a functional relationship exists between the thyroid gland and digestive physiology in the adult toad. Three doses of thyroxine (25 microg/100 g; 50 microg/100 g; 100 microg/100 microg body weight) were orally administered daily to the adult male toad, Bufo melanostictus and changes in -amylase, pepsin, trypsin, and esterase activities of the different zones of the digestive tract, pancreas and liver were observed. The observations were made on 7, 15, and 30 days of thyroxine treatment. The result shows that the dose of 25 microg increases the enzyme activities in the gastrointestinal tract, liver and pancreas of 7 days treatment. However, prolonged treatment with all the doses shows little effect on these enzymes. The pattern of changes in the enzymatic activities in the digestive tract of the adult male toads show more advanced compartmentalization than that of fishes. It is also found that site-specific enzyme production is not pronounced in this amphibious vertebrate. It is proposed that a positive functional relationship between thyroxine and digestive enzymes exists in the adult male toad.     

Effect of weaning terms and protein deficit in rat pup nutrition on activities of digestive enzymes

Restriction of protein in nutrition of rat pups weaned at different terms has been found to produce changes in activities of digestive enzymes (maltase, alkaline phosphatase, aminopeptidase M, and glycyl-L-leucine dipeptidase) in the small and large intestine both at once after cessation of nutrition with low-protein diet for 10 days and 4 months later. In adult animals after the earlier or later weaning there are observed not only a decrease or increase of the enzyme activities, but also a different type of distribution of the alkaline phosphatase activity along the small intestine, which is more pronounced in the lately weaned rats. Thus, disturbance of metabolic programming of enzyme systems of the small and large intestine due to a change of quality of nutrition in early ontogenesis depends on terms of weaning of animals.     

Effects of a testicotoxic dose of cadmium on the liver and drug metabolism in the rat

1. The effect of an acute testicotoxic dose of cadmium (CdCl2.H2O, 2.0 mg/kg i.p.) on liver morphology and drug-metabolizing enzyme activities were studied in adult male and female rats. 2. Cd treatment to female rats caused a slight and reversible decrease in hepatic microsomal aryl hydrocarbon hydroxylase (AHH) and aminopyrine N-demethylase (APND) activities. 3. No significant changes were noted in the liver morphology, serum alanine aminotransferase activities, enzyme induction by phenobarbital and 3-methylcholanthrene, and glucuronosyl-transferase (GT) and glutathione S-transferase (GST) activities. 4. The same Cd treatment to male rats, however, resulted in a much more pronounced and prolonged reduction in AHH and APND activities, which was attributable to a Cd-induced testicular necrosis and, hence, impairment of androgen secretion. 5. Accordingly, Cd treatment to castrated male rats did not lower the enzyme activities any further, and full recovery of activities was obtained after the administration of testosterone. 6. Both GT and GST, the two sex-independent enzymes, were not significantly affected by either Cd or gonadectomy in the male rat. 7. The present data show that a low acute dose of Cd induces chemical castration without severely altering hepatic function.     

Amelioration of some metabolic effects produced by hyperthyroidism in late pregnant rats and their fetuses. Effects on lipids and proteins.

We have studied the effect of 40-45 days administration of 1 mg/kg thyroxine on protein and lipid metabolism in liver, heart, lungs, kidneys and adrenal glands of virgin and 21-day pregnant rats and their fetuses and placentae. The chronic administration of thyroid hormone produced significant increases in serum T3 and T4 in both groups as well as in organ weights and protein concentrations in virgin rats, but much smaller modifications in pregnant ones. Hyperthyroidism decreased the weight of fetal livers and increased that of placentae; protein content was increased in all fetal organs. Hyperthyroidism induced increases in phospholipid concentrations in all the organs and in total lipids only in liver and heart of adult rats, which were not counteracted by pregnancy. Pregnant rats had increases in total lipids in liver and kidneys and in adrenal phospholipids. In hyperthyroid fetuses there was an increase in hepatic total lipids and no changes in phospholipids. Hepatic lipogenesis (measured by in vivo incorporation of 3H2O into lipids) was increased by hyperthyroidism in virgin and pregnant rats, but the increase was significantly smaller in the pregnant hyperthyroid rats compared with the virgin ones. Fetal lipogenesis in liver and lung was not changed. In addition, an increase was observed in lipogenic enzyme (fatty acid synthetase and glucose-6-phosphate dehydrogenase) activities in hyperthyroid virgin rats which was prevented by pregnancy. In fetuses only pulmonary glucose-6-phosphate dehydrogenase was increased when expressed in terms of tissue weight. Our results indicate that the metabolic effect of hyperthyroidism is attenuated in pregnant rats and their fetuses, when compared with adult virgin rats, in most of the parameters studied.(ABSTRACT TRUNCATED AT 250 WORDS)     

Changes in digestive enzymes through developmental and molt stages in the spiny lobster, Panulirus argus

Changes in major digestive enzymes through developmental and molt stages were studied for the spiny lobster Panulirus argus. There were significant positive relationships between specific activity of trypsin and amylase enzymes and lobster size, whereas esterase and lipase specific activities decreased as lobsters aged. No relationship was found between amylase/trypsin ratio and lobster size. Positive trends were found, however, for trypsin/lipase and amylase/lipase ratios. Results suggest that changes in enzyme activity respond to the lobsters' physiological needs for particular dietary components although multivariate analysis suggested that enzyme activities could be not totally independent of diet. On the other hand, the pattern of changes of major enzyme activities through molt cycle was similar for most enzymes studied. Following molt, trypsin, chymotrypsin, amylase, and lipase activities gradually increased to maximal levels at late intermolt (C4) and premolt (D). There were no variations in the electrophoretic pattern of digestive enzymes through developmental and molt stages and thus, it is demonstrated that regulation is exerted quantitatively rather than qualitatively. Further studies on the effect of other intrinsic and extrinsic factors on digestive enzyme activities are needed to fully understand digestive abilities and regulation mechanisms in spiny lobsters.     

Effect of hyperoxia acclimation on catalase and glutathione peroxidase activities and in vivo peroxidation products in various tissues of the frog Rana ridibunda perezi

Among vertebrates, adult amphibians are known to be especially tolerant to exposure to high environmental oxygen tensions. To clarify the basis for this high O2 tolerance, adult Rana ridibunda perezi frogs were acclimated for 15 days to water-air phases with either 149 mm Hg O2 (normoxia) or 710 mm Hg O2 (hyperoxia). At the end of the acclimation, various morphometric and biochemical parameters related to oxidative stress were measured in seven organs and tissues. Hyperoxia acclimation did not change either the total weight of the animals or the total and relative wet weights of the organs studied, except for the brain, which showed weight increases in the hyperoxic group. In vivo tissue peroxidation increased in the kidney; decreased in the skeletal muscle and skin; and did not change in the liver, lung, brain, and heart after hyperoxic exposures. Whereas liver, lung, and skin showed glutathione peroxidase (GSH-Px) activities with both cumene hydroperoxide (cumene-OOH) and H2O2 as substrates, skeletal muscle only showed H2O2 GSH-Px activity. Hyperoxia acclimation did not change either catalase (CAT) or GSH-Px activities in any organ, except for the liver in which CAT activity was induced by hyperoxia. Thus hyperoxia tolerance in this species does not need the induction of H2O2-detoxifying enzymes in the majority of the organs. It is suggested that the high O2 tolerance of this amphibian species is related to its comparatively high constitutive GSH-Px activities.     

pH值对中国龙虾消化酶活力的影响

采用酶学分析方法研究了pH对中国龙虾胃蛋白酶、类胰蛋白酶、淀粉酶、纤维素酶和脂肪酶活力的影响。结果表明,在设定的pH范围内,中国龙虾各消化酶的活力均随着pH的升高呈现先升后降的变化趋势。其中,胃、肠、肝胰腺内胃蛋白酶最适pH均为2.2,类胰蛋白酶最适pH分别为8.8-9.2、8.4、8.8,淀粉酶最适pH分别为7.0、7.0、7.4,纤维素酶最适pH分别为4.2、4.2-4.6、5.4,脂肪酶最适pH分别为7.2-7.6、7.2、6.8-7.2。同时测得中国龙虾胃、肠、肝胰腺内的生理pH分别为5.33、6.93、6.60。中国龙虾的消化酶活力存在器官特异性。在最适pH下,胃蛋白酶活力顺序为胃>肠>肝胰腺,类胰蛋白酶、纤维素酶、脂肪酶的活力顺序均为肝胰腺>肠>胃,淀粉酶的活力顺序为肠>肝胰腺>胃。