scholarly journals The distribution of the components of mixed-function oxidase between the rough and the smooth endoplasmic reticulum of liver cells

1968 ◽  
Vol 110 (3) ◽  
pp. 407-412 ◽  
Author(s):  
J. L. Holtzman ◽  
T. E. Gram ◽  
P. L. Gigon ◽  
J. R. Gillette
Keyword(s):  
Endoplasmic Reticulum ◽  
Smooth Endoplasmic Reticulum ◽  
Reductase Activity ◽  
Mixed Function Oxidase ◽  
Protein Ratio ◽  
Nadph Cytochrome ◽  
Rate Limiting Step ◽  
Significant Difference ◽  
The Difference ◽  
Cytochrome P 450

Mixed-function oxidase activity, when measured by the N-demethylation of ethylmorphine or the hydroxylation of aniline, is significantly higher in the smooth hepatic endoplasmic reticulum than in the rough. In the rabbit the smooth membrane/rough membrane activity ratios are significantly greater than 1 whether the activities are expressed per g. of liver (ratio 5), per mg. of protein (ratio 3–5), per μg. of phospholipid phosphorus (ratio 2), per unit of cytochrome P-450 (ratio 1·7) or per unit of NADPH–cytochrome c reductase activity (ratio 2). On the other hand, if the activities are normalized to the NADPH–cytochrome P-450 reductase, there is no significant difference between the rough and smooth membranes. These results suggest that, in the rabbit, the rate-limiting step is the reduction of cytochrome P-450. In contrast, in the rat the difference in activities can be explained by differences in the concentration of cytochrome P-450.

scholarly journals Asymmetric distribution of cytochrome P-450 and NADPH–cytochrome P-450 (cytochrome c) reductase in vesicles from smooth endoplasmic reticulum of rat liver

1980 ◽  
Vol 190 (3) ◽  
pp. 737-746 ◽  
Author(s):  
Michael B. Cooper ◽  
John A. Craft ◽  
Margaret R. Estall ◽  
Brian R. Rabin
Keyword(s):  
Endoplasmic Reticulum ◽  
Cytochrome C ◽  
Rat Liver ◽  
Smooth Endoplasmic Reticulum ◽  
Reductase Activity ◽  
Asymmetric Distribution ◽  
Trypsin Treatment ◽  
Cytochrome C Reductase ◽  
Nadph Cytochrome ◽  
Cytochrome P 450

1. The topography of cytochrome P-450 in vesicles from smooth endoplasmic reticulum of rat liver has been examined. Approx. 50% of the cytochrome is directly accessible to the action of trypsin in intact vesicles whereas the remainder is inaccessible and partitioned between luminal-facing or phospholipid-embedded loci. Analysis by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis reveals three major species of the cytochrome. Of these, the variant with a mol.wt. of 52000 is induced by phenobarbitone and this species is susceptible to trypsin. 2. After trypsin treatment of smooth membrane, some NADPH–cytochrome P-450 (cytochrome c) reductase activity remains and this remaining activity is enhanced by treatment with 0.05% deoxycholate, which renders the membranes permeable to macromolecules. In non-trypsin-treated control membranes the reductase activity is increased to a similar extent. These observations suggest an asymmetric distribution of NADPH–cytochrome P-450 (cytochrome c) reductase in the membrane. 3. As compared with dithionite, NADPH reduces only 44% of the cytochrome P-450 present in intact membranes. After tryptic digestion, none of the remaining cytochrome P-450 is reducible by NADPH. 4. In the presence of both a superoxide-generating system (xanthine plus xanthine oxidase) and NADPH, all the cytochrome P-450 in intact membrane (as judged by dithionite reducibility) is reduced. The cytochrome P-450 remaining after trypsin treatment of smooth vesicles cannot be reduced by this method. 5. The superoxide-dependent reduction of cytochrome P-450 is prevented by treatment of the membranes with mersalyl, which inhibits NADPH–cytochrome P-450 (cytochrome c) reductase. Thus the effect of superoxide may involve NADPH–cytochrome P-450 reductase and cytosolically orientated membrane factor(s).

Ultrastructure and Drug Metabolism in the Developing Guinea Pig

1973 ◽  
Vol 31 ◽  
pp. 538-539
Author(s):  
W. Kuenzig ◽  
M. Boublik ◽  
J.J. Kamm ◽  
J.J. Burns
Keyword(s):  
Guinea Pig ◽  
Metabolic Activity ◽  
Animal Species ◽  
Adult Animal ◽  
Smooth Endoplasmic Reticulum ◽  
Fetal Life ◽  
Mixed Function Oxidase ◽  
Cytochrome P 450 ◽  
Microsomal Mixed Function Oxidase ◽  
Mixed Function Oxidase Activity

Unlike a variety of other animal species, such as the rabbit, mouse or rat, the guinea pig has a relatively long gestation period and is a more fully developed animal at birth. Kuenzig et al. reported that drug metabolic activity which increases very slowly during fetal life, increases rapidly after birth. Hepatocytes of a 3-day old neonate metabolize drugs and reduce cytochrome P-450 at a rate comparable to that observed in the adult animal. Moreover the administration of drugs like phenobarbital to pregnant guinea pigs increases the microsomal mixed function oxidase activity already in the fetus.Drug metabolic activity is, generally, localized within the smooth endoplasmic reticulum (SER) of the hepatocyte.

scholarly journals Oocytes with smooth endoplasmic reticulum aggregates do not impact blastocyst euploidy rate

2021 ◽  
Author(s):  
Jian Xu ◽  
Li Yang ◽  
Zhi-Heng Chen ◽  
Min-Na Yin ◽  
Juan Chen ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Smooth Endoplasmic Reticulum ◽  
Formation Rate ◽  
Tertiary Hospital ◽  
Fertilization Rate ◽  
Blastocyst Formation ◽  
Preimplantation Genetic Testing ◽  
Significant Difference ◽  
Normal Fertilization ◽  
Euploidy Rate

Abstract Objective: To investigate whether the euploidy rate of blastocysts derived from smooth endoplasmic reticulum (SERa) positive cycles and oocytes are impacted.Design: Retrospective cohort study.Setting: A tertiary hospital-based reproductive medicine center.Patient(s): A total of 601 preimplantation genetic testing (PGT) cycles with obtained oocytes in our center between April 2017 and May 2021 were included in the study. Intervention(s): Women＞35 years and PGT cycles with chromosomal structural rearrangements (PGT-SR) were excluded. Embryological and blastocyst ploidy outcomes were compared between SERa+ oocyte, sibling SERa- oocytes and oocytes in SERa- cycles.Main Outcome Measure(s): Embryological outcomes and blastocyst euploidy rate.Results: No significant difference was observed in the normal fertilization rate (82.1 % vs. 77.8 % vs. 83.1 %, respectively, P=0.061), blastocyst formation rate (71.0 % vs. 72.5 % vs. 68.4 %, respectively, P=0.393), good quality blastocyst formation rate (46.4 % vs. 48.3 % vs. 42.6 %, respectively, P=0.198) between the SERa+ oocyte group, sibling SERa- oocyte group and SERa- oocyte group. No significant difference was observed in the euploidy rate (50.0 % vs. 62.5 % vs. 63.3 %, respectively, P=0.324), mosaic rate (12.5 % vs. 9.7 % vs. 13.4 %, respectively, P=0.506) and aneuploidy rate (37.5 % vs. 27.8% vs. 23.2 %, respectively, P=0.137) between the three groups.Conclusion: Our results suggest that the euploidy rate of blastocysts derived from SERa+ cycles and oocytes are not impacted.

scholarly journals Significance of serum-pleural effusion albumin gradient in differentiating transudative and exudative pleural effusions in comparison to light’s criteria

2017 ◽  
Vol 4 (2) ◽  
pp. 457
Author(s):  
Sujatha G. ◽  
Vindhya P. ◽  
Kalyan Kumar K.
Keyword(s):  
Pleural Effusion ◽  
Clinical Outcome ◽  
Pleural Fluid ◽  
Venous Blood ◽  
P Value ◽  
Protein Ratio ◽  
Clinical Disorder ◽  
Significant Difference ◽  
The Difference ◽  
Sensitivity Specificity

Background: Approximately one million patients develop pleural effusion every year. It is a common clinical disorder and is either a manifestation or a complication of one or other respiratory or non-respiratory disorders. It leads to serious prognosis, if not diagnosed and treated properly. To calculate SEAG and Light’s criteria and to compare SEAG with Light’s criteria in analyzing pleural effusions.Methods: A total of hundred patients were selected for the study. Pleural fluid of patients who met the inclusion and exclusion criteria were collected, when pleural fluid is being tapped for diagnostic thoracocentesis. Venous blood sample was collected along with diagnostic thoracocentesis or within 24 hours of thoracocentesis.  Written informed consent was obtained from them for thoracocentesis.Results: In our study we compared the clinical outcome with outcome as per Pleural fluid/Serum protein ratio (p value of <0.0001), pleural fluid/serum LDH (p value of <0.0001) and pleural fluid LDH (p value of <0.0001) separately and the p values were statistically significant. The sensitivity, specificity, PPV and NPV of Light’s criteria were 77.2%, 100%, 100%, 93.9% respectively. We compared Light’s criteria outcome with clinical outcome and the difference was statistically significant (p value of <0.0001). SEAG showed 100% sensitivity, 97.43% specificity, 91.6% PPV and is 91.66% and NPV is 100%. We compared the clinical outcome with SEAG and there was statistically significant difference (p value of <0.0001). We compared SEAG with Light’s criteria and the difference was statistically significant (p <0.0001). We compared Light’s plus pleural fluid protein gradient with SEAG and the difference is statistically significant (p value of <0.0001).Conclusions: SEAG is more sensitive for classifying transudates and more specific for exudates than Light’s criteria.

NADPH cytochrome P-450 reductase and its role in the mixed function oxidase reaction

1980 ◽  
Vol 8 (3) ◽  
pp. 525-537 ◽  
Author(s):  
Henry W. Strobel ◽  
John David Dignam ◽  
James R. Gum
Keyword(s):  
Mixed Function Oxidase ◽  
Nadph Cytochrome ◽  
Oxidase Reaction ◽  
Cytochrome P 450

scholarly journals Immunochemical characterization of NADPH-cytochrome P-450 reductase from Jerusalem artichoke and other higher plants

1989 ◽  
Vol 259 (3) ◽  
pp. 847-853 ◽  
Author(s):  
I Benveniste ◽  
A Lesot ◽  
M P Hasenfratz ◽  
F Durst
Keyword(s):  
Cytochrome C ◽  
Rat Liver ◽  
Higher Plants ◽  
Polyclonal Antibodies ◽  
Reductase Activity ◽  
Jerusalem Artichoke ◽  
Cross Reactivity ◽  
Cytochrome C Reductase ◽  
Nadph Cytochrome ◽  
Cytochrome P 450

Polyclonal antibodies were prepared against NADPH-cytochrome P-450 reductase purified from Jerusalem artichoke. These antibodies inhibited efficiently the NADPH-cytochrome c reductase activity of the purified enzyme, as well as of Jerusalem artichoke microsomes. Likewise, microsomal NADPH-dependent cytochrome P-450 mono-oxygenases (cinnamate and laurate hydroxylases) were efficiently inhibited. The antibodies were only slightly inhibitory toward microsomal NADH-cytochrome c reductase activity, but lowered NADH-dependent cytochrome P-450 mono-oxygenase activities. The Jerusalem artichoke NADPH-cytochrome P-450 reductase is characterized by its high Mr (82,000) as compared with the enzyme from animals (76,000-78,000). Western blot analysis revealed cross-reactivity of the Jerusalem artichoke reductase antibodies with microsomes from plants belonging to different families (monocotyledons and dicotyledons). All of the proteins recognized by the antibodies had an Mr of approx. 82,000. No cross-reaction was observed with microsomes from rat liver or Locusta migratoria midgut. The cross-reactivity generally paralleled well the inhibition of reductase activity: the enzyme from most higher plants tested was inhibited by the antibodies; whereas Gingko biloba, Euglena gracilis, yeast, rat liver and insect midgut activities were insensitive to the antibodies. These results point to structural differences, particularly at the active site, between the reductases from higher plants and the enzymes from phylogenetically distant plants and from animals.

scholarly journals Presence of nadph-cytochrome P-450 reductase in rat liver golgi membranes: Evidence obtained by immunoadsorption method

1978 ◽  
Vol 79 (2) ◽  
pp. 590-597 ◽  
Author(s):  
A Ito ◽  
GE Palade
Keyword(s):  
Rat Liver ◽  
Reductase Activity ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Nadph Cytochrome ◽  
Golgi Membranes ◽  
Cyt C ◽  
Bona Fide ◽  
Liver Homogenates ◽  
Cytochrome P 450

Light Golgi fractions (GF(1+2)) prepared from rat liver homogenates by a modification of the Ehrenreich et al. procedure (J. Cell Biol. 59:45) had significant NADPH-cytochrome P(450) reductase (NADPH-cyt c reductase) activity if assayed immediately after their isolation. An antibody raised in rabbits against purified microsomal and Golgi fractions. To find out whether this activity is located in bona fide Golgi elements or in contaminating microsomal vesicles, we used the following 3-step immunoadsorption procedure: (a) antirabbit IgG (raised in goats) was conjugated to small (2-5 μm) polycrylamide (PA) beads; (b) rabbit anti NADPH-cyt c reductase was immunoadsorbed to the antibody-coated beads; and (c) GF(1+2) was reacted with the beads carrying the two successive layers of antibodies. The beads were then recovered by centrifugation, and were washed, fixed, embedded in agarose, and processed for transmission electromicroscopy. Antireductase- coated beads absorbed 60 percent of the NADPH-cyt c reductase (and comparable fractions of NADH-cyt c reductase and glucose-6-phosphatase) but only 20 percent of the galactosyltransferase activity of the input GF(1+2). Differential vesicle counts showed that approximately 72 percent of the immunoadsorbed vesicles were morphologically recognizable Golgi elements (vesicles with very low density lipoprotein [VLDL] clusters or Golgi cisternae); vesicles with single VLDL and smooth surfaced microsome-like vesicles were too few (approximately 25 percent) to account for the activity. It is concluded that NADPH-cytochrome P(450) reductase is a Golgi membrane enzyme of probably uneven distribution among the elements of the Golgi complex.

Sign in / Sign up

Export Citation Format

Share Document