INACTIVATION AND DEGRADATION OF PORCINE CALCITONIN BY RAT LIVER, AND RELATIVE STABILITY OF SALMON CALCITONIN

1970 ◽  
Vol 48 (2) ◽  
pp. 181-188 ◽  
Author(s):  
M. de LUISE ◽  
T. J. MARTIN ◽  
R. A. MELICK
Keyword(s):  
Biological Activity ◽  
Rat Liver ◽  
Salmon Calcitonin ◽  
Trichloroacetic Acid ◽  
Maximal Activity ◽  
Active Principle ◽  
Rat Tissues ◽  
Prolonged Action ◽  
High Potency ◽  
Dose Dependent

SUMMARY Slices and homogenates of a number of rat tissues inactivated porcine calcitonin labelled with 125I; the most active tissue was the liver. Maximal activity was found in rat liver supernatant. The reaction was pH- and dose-dependent, the active principle was non-diffusible, inhibited by p-chloromercuribenzoate and EDTA, and destroyed by heat. Biological activity of calcitonin was lost parallel with the breakdown of the labelled calcitonin (as measured by loss of trichloroacetic acid precipitability). Salmon ultimobranchial calcitonin was much less susceptible to inactivation by rat liver supernatant than the porcine hormone, which may explain the high potency and prolonged action of the salmon hormone in the rat.

scholarly journals Citrulline synthesis in rat tissues and liver content of carbamoyl phosphate and ornithine

1974 ◽  
Vol 138 (2) ◽  
pp. 225-232 ◽  
Author(s):  
Luisa Raijman
Keyword(s):  
Rat Liver ◽  
Soluble Fraction ◽  
Maximal Activity ◽  
Rat Tissues ◽  
Ornithine Carbamoyltransferase ◽  
Carbamoyl Phosphate Synthetase ◽  
Carbamoyl Phosphate ◽  
Citrulline Synthesis

Rat liver ornithine carbamoyltransferase appears to be located exclusively in the mitochondria; the activity that is found in the soluble fraction is indistinguishable from mitochondrial ornithine carbamoyltransferase by simple kinetic criteria, and seems to result from breakage of mitochondria during homogenization. Of several rat tissues studied, only the liver and the mucosa of small intestine contain significant amounts of ornithine carbamoyltransferase; the activity in intestinal mucosa is less than one thousandth of that in liver. Qualitatively, this distribution coincides with that of carbamoyl phosphate synthetase I and its cofactor, acetylglutamate. The rat liver contents of carbamoyl phosphate and ornithine were 0.1 and 0.15μmol/g wet wt. of tissue respectively. On the basis of these values, it is proposed that in vivo the ornithine carbamoyltransferase activity of liver may be much lower than its maximal activity in vitro might suggest.

Melatonin actions in the heart; more than a hormone

2018 ◽  
Vol 1 (1) ◽  
pp. 21-26 ◽  
Author(s):  
Darío Acuña-Castroviejo ◽  
Maria T Noguiera-Navarro ◽  
Russel J Reiter ◽  
Germaine Escames
Keyword(s):  
Cell Membranes ◽  
Myocardial Cell ◽  
Rat Tissues ◽  
Dependent Manner ◽  
Broad Distribution ◽  
Multiple Organs ◽  
High Doses ◽  
Extrapineal Melatonin ◽  
Dose Dependent ◽  
Different Doses

Due to the broad distribution of extrapineal melatonin in multiple organs and tissues, we analyzed the presence and subcellular distribution of the indoleamine in the heart of rats. Groups of sham-operated and pinealectomized rats were sacrificed at different times along the day, and the melatonin content in myocardial cell membranes, cytosol, nuclei and mitochondria, were measured. Other groups of control animals were treated with different doses of melatonin to monitor its intracellular distribution. The results show that melatonin levels in the cell membrane, cytosol, nucleus, and mitochondria vary along the day, without showing a circadian rhythm. Pinealectomized animals trend to show higher values than sham-operated rats. Exogenous administration of melatonin yields its accumulation in a dose-dependent manner in all subcellular compartments analyzed, with maximal concentrations found in cell membranes at doses of 200 mg/kg bw melatonin. Interestingly, at dose of 40 mg/kg b.w, maximal concentration of melatonin was reached in the nucleus and mitochondrion. The results confirm previous data in other rat tissues including liver and brain, and support that melatonin is not uniformly distributed in the cell, whereas high doses of melatonin may be required for therapeutic purposes.

METABOLISM OF 17α-HYDROXYPROGESTERONE-4-14C-17α-CAPROATE BY HOMOGENATES OF RAT LIVER AND HUMAN PLACENTA

1961 ◽  
Vol 36 (4) ◽  
pp. 511-519 ◽  
Author(s):  
Margaret Wiener ◽  
Charles I. Lupa ◽  
E. Jürgen Plotz
Keyword(s):  
Rat Liver ◽  
Human Placenta ◽  
Steric Hindrance ◽  
Placental Tissue ◽  
Caproic Acid ◽  
Major Product ◽  
Side Chain ◽  
Anaerobic Conditions ◽  
Prolonged Action ◽  
Long Acting

ABSTRACT 17α-hydroxyprogesterone-4-14C-17α-caproate (HPC), a long-acting progestational agent, was incubated with homogenates of rat liver and human placenta. The rat liver was found to reduce Ring A of HPC under anaerobic conditions to form allopregnane-3β,17α-diol-20-one-17α-caproate and pregnane-3β,17α-diol-20-one-17α-caproate, the allopregnane isomer being the major product. The caproic acid ester was neither removed nor altered during the incubation. Placental tissue did not attack HPC under conditions where the 20-ketone of progesterone was reduced. It is postulated that this absence of attack on the side chain is due to steric hindrance from the caproate ester, and that this may account for the prolonged action of HPC.

BIOSYNTHESE DE LA TRANSCORTINE

1969 ◽  
Vol 62 (3) ◽  
pp. 468-476 ◽  
Author(s):  
Jeanine Guidollet ◽  
Pierre Louisot
Keyword(s):  
Biological Activity ◽  
Rat Liver ◽  
Liver Cell ◽  
Binding Activity ◽  
Subcellular Level

ABSTRACT Corticosteroid-binding activity (transcortin) was investigated at the subcellular level of the rat liver cell: it was located exclusively in the cell sap, and not on the ribosomes or membranes. Oestrogens were found to increase the biological activity of this glycoprotein (corticosterone binding) in the plasma and in the cell sap. The isotopic activity of the glucidic fragments of glycoprotein (after incorporation of 14C-D-glucosamine), however, remained constant or decreased in the specific subcellular sites at which they were incorporated (membranes and cell sap). This absence of correlation between these two results is not in agreement with an induction of transcortin synthesis by oestrogens, but in favour of an activation of normally masked molecular sites.

Hepatic uptake of intact glutathione S-conjugate, inhibition by organic anions, and sinusoidal catabolism

1993 ◽  
Vol 265 (3) ◽  
pp. G547-G554
Author(s):  
C. A. Hinchman ◽  
A. T. Truong ◽  
N. Ballatori
Keyword(s):  
Guinea Pig ◽  
Rat Liver ◽  
Marked Decrease ◽  
Hepatic Uptake ◽  
Half Time ◽  
High Concentrations ◽  
Rat Livers ◽  
Dose Dependent ◽  
Uptake And Metabolism ◽  
Guinea Pig Liver

To identify potential mechanisms for hepatic removal of circulating glutathione (GSH) conjugates, uptake and metabolism of S-2,4-dinitrophenylglutathione (DNP-SG) were examined in isolated perfused livers from rat and guinea pig. Guinea pig livers perfused with 5 mumol of DNP-SG in a recirculating system (50 microM initial concn) rapidly cleared the conjugate from the perfusate (half time 3.7 min), whereas clearance was considerably slower in rat liver (half time 35 min). Disappearance of DNP-SG from the perfusate was accompanied by a simultaneous appearance of DNP-SG and its metabolites in bile. Addition of acivicin, an inhibitor of gamma-glutamyltransferase (gamma-GT), to the perfusate resulted in a marked decrease in DNP-SG clearance by guinea pig liver but had no effect in rat liver, suggesting that in the guinea pig this process is largely dependent on sinusoidal gamma-GT activity. However, even in the presence of acivicin, rat and guinea pig livers removed nearly one-half of the administered DNP-SG from the recirculating perfusate over 30 min. High concentrations of DNP-SG were found in bile (up to 3.7 mM), indicating that the liver is capable of transporting the intact conjugate from the circulation. When rat livers were perfused with higher concentrations of DNP-SG (100 and 250 microM), biliary excretion of DNP-SG increased dose dependently, with concentrations in bile reaching 10 mM at the higher dose. This was accompanied by a dose-dependent choleresis.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Properties of subunits of the multicatalytic proteinase complex revealed by the use of subunit-specific antibodies

1991 ◽  
Vol 278 (1) ◽  
pp. 171-177 ◽  
Author(s):  
A J Rivett ◽  
S T Sweeney
Keyword(s):  
Molecular Mass ◽  
Rat Liver ◽  
Gel Filtration ◽  
Immunoblot Analysis ◽  
Rat Tissues ◽  
Specific Antibodies ◽  
Multicatalytic Proteinase ◽  
Cell Extracts ◽  
Liver And Kidney ◽  
Lysosomal Proteinase

The multicatalytic proteinase (MCP) is a high-molecular-mass non-lysosomal proteinase that gives rise to a characteristic pattern of bands of molecular mass 22-34 kDa on SDS/PAGE gels. Isoelectric-focusing gels of the enzyme purified from rat liver show 16 bands with isoelectric points in the range of pH 5-8.5. Two-dimensional PAGE gels reveal that there are more than the previously reported 13 polypeptides associated with the MCP from rat liver and show a pattern of 15-20 major spots and several minor ones, similar to that of MCP isolated from some other sources. Possible relationships between the different polypeptides were investigated by immunoblot analysis of electrophoretically purified proteinase subunits with affinity-purified subunit-specific antibodies as well as antibodies raised against individual denatured subunits of the complex. The results demonstrate that many of the major polypeptide components of the MCP complex are antigenically distinct. Moreover comparison of immunoreactive material in crude cell extracts with that in purified MCP preparations has shown that the polypeptides are not derived from a smaller number of higher-molecular-mass subunits. Also, individual subunits have the same apparent molecular mass in a variety of rat tissues, suggesting close similarity between MCPs of different tissues. The highest concentrations of MCP subunits occur in liver and kidney. Gel-filtration analysis of crude extracts has demonstrated that MCP polypeptides are also associated with a higher-molecular-mass complex, which may be the 26 S proteinase that has been implicated in the degradation of ubiquitin-protein conjugates.

scholarly journals Complexing of the CD-3 subunit by a monoclonal antibody activates a microtubule-associated protein 2 (MAP-2) serine kinase in Jurkat cells

1989 ◽  
Vol 262 (2) ◽  
pp. 449-456 ◽  
Author(s):  
C Hanekom ◽  
A Nel ◽  
C Gittinger ◽  
A Rheeder ◽  
G Landreth
Keyword(s):  
T Cells ◽  
Time Course ◽  
Gel Filtration ◽  
Maximal Activity ◽  
Jurkat Cells ◽  
Serine Kinase ◽  
Transient Activation ◽  
Normal Human ◽  
Dose Dependent

Treatment of Jurkat T-cells with anti-CD-3 monoclonal antibodies resulted in the rapid and transient activation of a serine kinase which utilized the microtubule-associated protein, MAP-2, as a substrate in vitro. The kinase was also activated on treatment of Jurkat cells with phytohaemagglutinin, but with a different time course. The activation of the MAP-2 kinase by anti-CD-3 antibodies was dose-dependent, with maximal activity observed at concentrations of greater than 500 ng/ml. Normal human E-rosette-positive T-cells also exhibited induction of MAP-2 kinase activity during anti-CD-3 treatment. The enzyme was optimally active in the presence of 2 mM-Mn2+; lower levels of activity were observed with Mg2+, even at concentrations up to 20 mM. The kinase was partially purified by passage over DE-52 Sephacel with the activity eluting as a single peak at 0.25 M-NaCl. The molecular mass was estimated to be 45 kDa by gel filtration. The activation of the MAP-2 kinase was probably due to phosphorylation of this enzyme as treatment with alkaline phosphatase diminished its activity. These data demonstrate that the stimulation of T-cells through the CD-3 complex results in the activation of a novel serine kinase which may be critically involved in signal transduction in these cells.

scholarly journals Comparison of Different Methods for Extracting the Astaxanthin from Haematococcus pluvialis: Chemical Composition and Biological Activity

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3569
Author(s):  
Yicheng Tan ◽  
Zhang Ye ◽  
Mansheng Wang ◽  
Muhammad Faisal Manzoor ◽  
Rana Muhammad Aadil ◽  
...  
Keyword(s):  
High Pressure ◽  
Biological Activity ◽  
Chemical Composition ◽  
Haematococcus Pluvialis ◽  
Activity Analysis ◽  
Cell Disruption ◽  
Dependent Manner ◽  
Dpph Activity ◽  
The Impact ◽  
Dose Dependent

In this study, the impact of different cell disruption techniques (high-pressure micro fluidization (HPMF), ionic liquids (ILs), multi-enzyme (ME), and hydrochloric acid (HCl)) on the chemical composition and biological activity of astaxanthin (AST) obtained from Haematococcus pluvialis was investigated. Results indicated that all cell disruption techniques had a significant effect on AST composition, which were confirmed by TLC and UPC2 analysis. AST recovery from HCl (HCl-AST) and ILs (ILs-AST) cell disruption techniques was dominant by free and monoesters AST, while AST recovery from HPMF (HPMF-AST) and ME (ME-AST) cell disruption techniques was composed of monoesters, diesters, and free AST. Further biological activity analysis displayed that HCl-AST showed the highest ABTS and DPPH activity, while ILs-AST showed better results against the ORAC assay. Additionally, ILs-AST exhibits a stronger anti-proliferation of HepG2 cells in a dose-dependent manner, which was ascribed to AST-induced ROS in to inhibit the proliferative of cancer cells.

Human MutT Homolog 1 (MTH1) Inhibitor Reduces the Biological Activity of Ovarian Carcinoma Cells

2022 ◽  
Vol 12 (5) ◽  
pp. 907-913
Author(s):  
Liyan Zhong ◽  
Yi Yi ◽  
Qian Liu ◽  
Yan Peng
Keyword(s):  
Biological Activity ◽  
Ovarian Carcinoma ◽  
Biological Activities ◽  
Carcinoma Cells ◽  
Dependent Manner ◽  
Ovarian Carcinoma Cells ◽  
Proliferative Rate ◽  
Skov3 Cells ◽  
Significant Difference ◽  
Dose Dependent

This study intends to discuss the mechanism of MTH1 inhibitor (TH588) in the biological activity of ovarian carcinoma cells. A2780 and SKOV-3 cells were treated with different concentrations of TH588 and assigned into AT group (control), BT group (8 μmol/L TH588), CT group (16 μmol/L), DT group (32 μmol/L), ET group (64 μmol/L) and FT group (128 μmol/L) followed by measuring level of Bcl-2 and Bax by Western blot and PCR, and cell biological activities by MTT, FCM and Transwell chamber assay. The cell proliferative rate was not affected in AT group, but was lower in other groups in a reverse dose-dependent manner. There was significant difference on apoptotic rate and cell invasion among groups with increased apoptosis and reduce invasion after TH588 treatment. FT group showed lowest expression of Bcl-2 and Bax compared to other groups. In conclusion, the biological activity of A2780/SKOV3 cells could be reduced by MTH1 inhibitor which was probably through regulation of Bax and Bcl-2 expression.

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