scholarly journals Kinetic Behaviour of Glucose 6-Phosphate Dehydrogenase and 6-Phosphogluconate Dehydrogenase in Different Tissues of Rainbow Trout (Oncorhynchus mykiss) Exposed to Non-Lethal Concentrations of Cadmium

2009 ◽  
Vol 78 (1) ◽  
pp. 179-185 ◽  
Author(s):  
Olcay Hisar ◽  
Adem Yavuz Sönmez ◽  
Şükrü Beydemir ◽  
Şükriye Aras Hisar ◽  
Telat Yanik ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Dose Response ◽  
Enzyme Activities ◽  
Response Pattern ◽  
Base Line ◽  
Phosphogluconate Dehydrogenase ◽  
Liver And Kidney ◽  
Glucose 6 Phosphate Dehydrogenase

The effects of cadmium (Cd) on the enzymatic activities of glucose 6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD) were investigated in the gill, liver and kidney tissues of rainbow trout (Oncorhynchus mykiss). Three test groups of fish were subjected to increasing concentrations (1, 3 and 5 mg/l) of cadmium (Cd) in vivo, respectively. The G6PD and 6PGD activities in the gill, liver, and kidney tissues of each group of fish were measured on days 1, 3, 5 and 7. G6PD and 6PGD enzyme activities, measured in gill, liver and kidney homogenates, were stimulated by various concentrations (1, 3, and 5 mg/l) of cadmium. Although the dose-response pattern of G6PD enzyme activities in liver and kidney tissue was very similar, that in gill was different from both other tissues. The enzyme activity of G6PD enzyme was significantly stimulated after three days (Day 3) in liver and kidney tissues at a dose of 1 mg/l Cd (p < 0.05), whereas it was stimulated on the first day of experiment (Day 1) in gill, liver and kidney tissues at doses of 3 and 5 mg/l Cd (p < 0.05). However, the activity of 6PGD was stimulated after three days (Day 3) in the liver at a dose of 1 mg/l Cd (p < 0.05) and on the first day in gill, liver and kidney tissues at doses of 3 and 5 mg/l Cd (p < 0.05). The stimulation effect of the 5 mg/l dose of Cd on G6PD and 6PGD enzyme activities was significantly diminished after seven days (Day 7) in all tissues (p < 0.05). In contrast to the dose-response pattern at the dose of 5 mg/l Cd, G6PD and 6PGD enzyme activities were stimulated significantly (p < 0.05) in liver and kidney tissues at the doses of 3 and 1 mg/l Cd. The stimulation effect of cadmium on the three tissues studied was also calculated; for both of the enzymes (G6PD and 6PGD), the enzyme activity levels were stimulated by approximately 60% and 38% in gills, 68% and 44% in liver, and 67% and 41% in kidneys, respectively, over the base-line enzyme activity of the control groups during the sevenday experimental period. These findings indicate that tissue G6PD and 6PGD enzymes function to protect against cadmium toxicity.

The induction by exogenous hormones of enzymes metabolising glucose 6-phosphate in the mammary gland of the pseudopregnant rabbit

1969 ◽  
Vol 36 (1) ◽  
pp. 47-52 ◽  
Author(s):  
R. J. Heitzman
Keyword(s):  
Enzyme Activity ◽  
Mammary Gland ◽  
Enzyme Activities ◽  
Synergistic Action ◽  
Phosphate Metabolism ◽  
Exogenous Hormones ◽  
Phosphogluconate Dehydrogenase ◽  
Intraductal Injection ◽  
Glucose 6 Phosphate Dehydrogenase

SummaryA study was made of the effects of the hormones, prolactin and cortisol acetate, on the activities in the mammary gland of the pseudopregnant rabbit of the enzymes concerned with lactose biosynthesis and glucose 6-phosphate metabolism, namely: UDP-glucose pyrophosphorylase, UDP-glucose-4'-epimerase, phosphofructokinase, phosphoglucomutase, glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase. Significant increases in enzyme activities were observed in rabbits examined 3 or 4 days after receiving a mammary intraductal injection of prolactin. The activities were not significantly increased at examination 2 days after injection of prolactin. Rabbits receiving cortisol acetate each day for 3 days also showed no significant increases in mammary enzyme activity. However, when prolactin and cortisol acetate were given simultaneously over a period of 3 days, increased enzyme activities were found suggesting synergistic action of the hormones.

Effects of different photoperiods on digestive enzyme activities in rainbow trout (Oncorhynchus mykiss) alevin and fry

2016 ◽  
Vol 94 (6) ◽  
pp. 435-442 ◽  
Author(s):  
Fereshteh Ramzanzadeh ◽  
Sakineh Yeganeh ◽  
Khosro JaniKhalili ◽  
Seyedeh Sedigheh Babaei
Keyword(s):  
Enzyme Activity ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Enzyme Activities ◽  
Digestive Enzyme ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
First Feeding ◽  
Significant Difference ◽  
Digestive Enzyme Activities ◽  
L 14

The aim of this study was to investigate the ontogeny of digestive enzymes and effects of photoperiod on pancreatic enzyme activity in rainbow trout (Oncorhynchus mykiss (Walbaum, 1792)) alevin and fry. After hatching, 3600 individuals of first-feeding alevin with a mean (±SD) mass of 119 ± 0.01 mg were reared in plastic tanks at four photoperiod levels (llight (L) : dark (D) cycle) for 6 weeks. Each replicate contained 300 alevin. Photoperiod treatments consisted of 14 h L : 10 h D, 10 h L : 14 h D, 4 h L : 20 h D, and 24 h L : 0 h D. During the rearing period, environmental variables including water temperature, oxygen, and pH were checked. Random sampling of alevin and fry was done at 0, 1, 3, 5, 8, 10, 15, 20, 25, 30, 39, and 44 days after the beginning of the first feeding (equal to 18, 19, 23, 25, 28, 30, 35, 40, 45, 50, 58, 63 days post hatching (dph)). The digestive enzyme activities in alevin and fry had a similar variation trend with age at all photoperiod levels. The specific activities of trypsin, chymotrypsin, and α-amylase at 24 h L : 0 h D were significantly higher than other treatments, but there was no significant difference in specific activity of lipase among treatments. The results demonstrated that growth, feeding efficiency, and digestive enzyme activity improved with longer exposure to photoperiod in rearing conditions.

Intrastrain and interstrain variability in biotransformation enzyme activities of rainbow trout (Oncorhynchus mykiss)

1997 ◽  
Vol 54 (12) ◽  
pp. 2901-2906 ◽  
Author(s):  
Kari Koponen ◽  
Ossi Ritola ◽  
Sirpa Huuskonen ◽  
Dan Linder ◽  
Katalin Monostory ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Enzyme Activities ◽  
Experimental Studies ◽  
Type Model ◽  
Cytochrome P450 Enzyme ◽  
Biotransformation Enzyme ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
P450 Enzyme ◽  
Liver And Kidney

We assessed the intrastrain and interstrain variability of cytochrome P450 enzyme activities and conjugation reactions of different rainbow trout (Oncorhynchus mykiss) strains. The study protocol was divided into two parts: in two separate experiments, monooxygenase (7-ethoxyresorufin O-deethylase, EROD) and conjugation (glutathione S-transferase, GST; UDP-glucuronosyl transferase, UDPGT) enzyme activities were measured from liver and kidney samples of commonly used rainbow trout breeds. In the preliminary study, the differences in the basal biotransformation enzyme activities were detected in two separately cultivated rainbow trout strains. Results indicated significant intrastrain (UDPGT, GST) and interstrain (EROD) differences in biotransformation enzyme activities. In the experimental study, corresponding enzyme activities were measured from three different rainbow trout strains exposed to beta -naphthoflavone (BNF), a polycyclic aromatic hydrocarbon (PAH) type model compound.The results revealed significant interstrain differences, especially in hepatic EROD and GST\b activities. However, UDPGT activities in the liver, as well as the measured monooxygenase and conjugation activities in the kidney, showed no notable variance between strains.The present work addresses intrastrain differences between hatcheries and highlights the need for intercalibration of rainbow trout strains used in experimental studies in aquatic toxicology.

Time-course of enzyme adaptation. I. Effects of substituting dietary glucose and fructose at constant concentrations of dietary protein

1968 ◽  
Vol 46 (12) ◽  
pp. 1459-1470 ◽  
Author(s):  
B. Szepesi ◽  
R. A. Freedland
Keyword(s):  
Enzyme Activity ◽  
Pyruvate Kinase ◽  
Dietary Protein ◽  
Malic Enzyme ◽  
Dietary Change ◽  
Phosphogluconate Dehydrogenase ◽  
Dietary Fructose ◽  
Liver And Kidney ◽  
Malic Enzyme Activity ◽  
Glucose 6 Phosphate Dehydrogenase

The effect of dietary fructose on liver, kidney, and adrenal enzymes was studied in male Sprague–Dawley rats. Dietary fructose increased relative liver and kidney sizes, liver glycogen, and liver protein. The percentage increases in relative liver and kidney sizes were independent of dietary protein, but relative liver sizes were smaller in the absence of protein.The activities of all the liver enzymes studied, except glucokinase, were increased by a 65% fructose diet containing 25% casein. The rates of increases differed between enzymes; the activities of L-α-glycerophosphate dehydrogenase and phosphoenolpyruvate carboxykinase (PEP-carboxykinase) reached almost maximum in 1 day, glucose 6-phosphatase, 6-phosphogluconate dehydrogenase, and pyruvate kinase activities reached maximum in about 2 days, and glucose 6-phosphate dehydrogenase, malic enzyme, dihydroxyacetone kinase, phosphofructose kinase, and phosphohexose isomerase required at least 3 days to reach maximum activity after the dietary change. The increases in the activities of liver fructose 1,6-diphosphatase, glucose 6-phosphate dehydrogenase, pyruvate kinase, and phosphohexose isomerase did not occur in the absence of dietary protein. The activities of liver phosphofructokinase and malic enzyme were increased equally well whether the fructose diet contained protein or not, while the increases in the activities of other enzymes were less in the absence of dietary protein.The half-life of liver malic enzyme was estimated as 3 days in the glucose to fructose dietary change and 1 day in the fructose to glucose dietary change. Since malic enzyme activity was increased by fructose feeding about threefold, the data suggest that under the conditions of the experiment fructose increased malic enzyme activity by decreasing the rate of breakdown of the enzyme.In general, kidney enzymes were affected by fructose to a lesser extent than the corresponding enzymes in liver. This was particularly significant in the case of kidney glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, and malic enzyme, the activities of which were only slightly increased in kidney. The activities of these three enzymes in the adrenal glands were not increased by fructose feeding.

scholarly journals Rat uterine microbiochemistry: metabolic enzyme activities stimulated by 17-beta-estradiol are localized in epithelial cells.

1987 ◽  
Vol 35 (6) ◽  
pp. 657-662 ◽  
Author(s):  
J P Holt ◽  
E Rhe
Keyword(s):  
Enzyme Activity ◽  
Smooth Muscle ◽  
Epithelial Cells ◽  
Dose Response ◽  
Enzyme Activities ◽  
Time Course ◽  
Citrate Synthase ◽  
Ovariectomized Rats ◽  
Similar Response ◽  
Estradiol Treatment

Lactate dehydrogenase (LDH; EC 1.1.1.27), citrate synthase (CS; EC 4.1.3.7), and beta-hydroxyacyl-CoA-dehydrogenase (beta-OH-acyl-CoA-DH; EC 1.1.1.35) activities were determined in each of the three major cell types of rat uterus, i.e., epithelial, stromal, and smooth muscle, using quantitative microanalytical techniques. Adult ovariectomized rats were treated with 17-beta-estradiol to determine the time course and dose response (0.025-50 micrograms/300-g rat) effect of estrogen on enzyme activity of each type of uterine cell. The use of "oil well" and enzyme-cycling microtechniques to determine the time course and the dose responses of enzyme activity changes required microassays involving 1595 microdissected single cell specimens. Estradiol treatment increased epithelial LDH, CS and beta-OH-acyl-CoA-DH activity but had no effect on these enzymes in the stroma or in smooth muscle cells. The estradiol-stimulated peak enzyme activities on Day 4 in the intervention group are compared with those in the ovariectomized rat controls as follows: LDH, 44.5 +/- 3.5 vs 22.3 +/- 3.9; CS, 3.5 +/- 0.2 vs 1.5 +/- 0.6; beta-OH-acyl-CoA-H, 3.5 +/- 0.32 vs 2.2 +/- 0.2 (mean +/- standard deviation; mol/kg/hr). Stromal cell activities (LDH, 7.4 +/- 1.0; CS, 1.2 +/- 0.2; beta-OH-acyl-CoA-DH, 0.9 +/- 0.1) were significantly lower than epithelial cell levels and were similar to smooth muscle levels. Therefore, even in the ovariectomized animal epithelial cells have markedly higher metabolic activity compared with adjacent cells. The enzyme activities are expressed as moles of substrate reacting per kilogram of dry weight per hour. All three enzymes exhibited a 17-beta-estradiol-induced dose response between 0.025-0.15 micrograms/300-g rat. The three enzymes studied all had similar response patterns to estrogen. The effect of estradiol was restricted to epithelial cells, with enzyme activities increasing to maximal levels after approximately 96 hr of hormone treatment. This study therefore not only confirms the specific and differential metabolic responses of uterine cells to estradiol treatment, but clearly demonstrates that marked metabolic differences exist between epithelial cells and stromal or smooth muscle uterine cells.

Inter-tissue differences in mitochondrial enzyme activity, RNA and DNA in rainbow trout (Oncorhynchus mykiss)

1998 ◽  
Vol 201 (24) ◽  
pp. 3377-3384 ◽  
Author(s):  
S. C. Leary ◽  
B. J. Battersby ◽  
C. D. Moyes
Keyword(s):  
Enzyme Activity ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Citrate Synthase ◽  
Mitochondrial Protein ◽  
Molecular Organization ◽  
Mitochondrial Rna ◽  
Mitochondrial Enzyme ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
The Relationship

We examined whether the relationships between mitochondrial enzyme activity, mitochondrial DNA (mtDNA) and mitochondrial RNA (mtRNA) were conserved in rainbow trout (Oncorhynchus mykiss) tissues that differ widely in their metabolic and molecular organization. The activity of citrate synthase (CS), expressed either per gram of tissue or per milligram of total DNA, indicated that these tissues (blood, brain, kidney, liver,cardiac, red and white muscles) varied more than 100-fold in mitochondrial content. Several-fold differences in the levels of CS mRNA per milligram of DNA and CS activity per CS mRNA were also observed, suggesting that fundamental differences exist in the regulation of CS levels across tissues. Although tissues varied 14-fold in RNA g-1, poly(A+) RNA (mRNA)was approximately 2 % of total RNA in all tissues. DNA g-1 also varied 14-fold across tissues, but RNA:DNA ratios varied only 2.5-fold. The relationship between two mitochondrial mRNA species (COX I, ATPase VI) and one mitochondrial rRNA (16S) species was constant across tissues. The ratio of mtRNA to mtDNA was also preserved across most tissues; red and white muscle had 10- to 20-fold lower levels of mtDNA g-1 but 7- to 10-fold higher mtRNA:mtDNA ratios, respectively. Collectively, these data suggest that the relationship between mitochondrial parameters is highly conserved across most tissues, but that skeletal muscles differ in a number of important aspects of respiratory gene expression ('respiratory genes'include genes located on mtDNA and genes located in the nucleus that encode mitochondrial protein) and mtDNA transcriptional regulation.

Sign in / Sign up

Export Citation Format

Share Document