INCREASE OF SERUM FREE THYROXINE FOLLOWING THE ADMINISTRATION OF THIOCYANATE AND OTHER ANIONS IN VIVO AND IN VITRO

1974 ◽  
Vol 75 (4) ◽  
pp. 707-716 ◽  
Author(s):  
N. Michajlovskij ◽  
P. Langer
Keyword(s):  
Time Course ◽  
Linear Increase ◽  
Free Thyroxine ◽  
Peroral Administration ◽  
Rat Serum ◽  
Serum Free ◽  
Serum Free Thyroxine

ABSTRACT Following the addition of thiocyanate (SCN−) to human and rat serum of 80 mg SCN−/ 100 ml (initial concentration before dialysis) a marked increase in serum free thyroxine (FT4) was found. The addition of equivalent doses of other antihyroid anions or permanganate showed a similar increase of FT4 in the order: BF4− < CIO4− = SCN− < MnO4−. The increase in the rat serum was greater than that in human serum. After peroral administration of these anions to the rats in amounts equal to 30 mg SCN−/rat the increase of FT4 was still higher. The addition of increased doses of SCN− to the human and rat sera (5-80 and up to 1600 mg SCN−/100 ml) caused a linear increase of FT4. Similarly, after the administration of various doses of SCN− to rats (5-30 mg SCN−/rat) a linear dose-response of the FT4 level in serum was observed. The time-course of the increase of % FT4 and absolute FT4 (AFT4) level after a single administration of SCN− to rats coincided with the increase of the serum SCN− level. However, after the disappearance of SCN− from the serum the % FT4 returned to the initial value, while the AFT4 was decreased. The effect of these anions probably consists in the competitive displacement of thyroxine from serum thyroxine-binding proteins. These and previous results suggested that thiocynate influences the plasma protein-thyroxine equilibrium and the possible role of an increased free thyroxine level on the action of thyroxine on various tissues and the hypothalamo-pituitary-thyroid feed-back is discussed.

scholarly journals Enhanced phosphorylation of Na+–Cl− co-transporter in experimental metabolic syndrome: role of insulin

2012 ◽  
Vol 123 (11) ◽  
pp. 635-647 ◽  
Author(s):  
Radko Komers ◽  
Shaunessy Rogers ◽  
Terry T. Oyama ◽  
Bei Xu ◽  
Chao-Ling Yang ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Time Course ◽  
Kinase Inhibitor ◽  
Endogenous Expression ◽  
The Metabolic Syndrome ◽  
Mammalian Cell Lines ◽  
Phosphoinositide 3 Kinase

In the present study, we investigated the activity of the thiazide-sensitive NCC (Na+–Cl− co-transporter) in experimental metabolic syndrome and the role of insulin in NCC activation. Renal responses to the NCC inhibitor HCTZ (hydrochlorothiazide), as a measure of NCC activity in vivo, were studied in 12-week-old ZO (Zucker obese) rats, a model of the metabolic syndrome, and in ZL (Zucker lean) control animals, together with renal NCC expression and molecular markers of NCC activity, such as localization and phosphorylation. Effects of insulin were studied further in mammalian cell lines with inducible and endogenous expression of this molecule. ZO rats displayed marked hyperinsulinaemia, but no differences in plasma aldosterone, compared with ZL rats. In ZO rats, natriuretic and diuretic responses to NCC inhibition with HCTZ were enhanced compared with ZL rats, and were associated with a decrease in BP (blood pressure). ZO rats displayed enhanced Thr53 NCC phosphorylation and predominant membrane localization of both total and phosphorylated NCC, together with a different profile in expression of SPAK (Ste20-related proline/alanine-rich kinase) isoforms, and lower expression of WNK4. In vitro, insulin induced NCC phosphorylation, which was blocked by a PI3K (phosphoinositide 3-kinase) inhibitor. Insulin-induced reduction in WNK4 expression was also observed, but delayed compared with the time course of NCC phosphorylation. In summary, we report increased NCC activity in hyperinsulinaemic rodents in conjunction with the SPAK expression profile consistent with NCC activation and reduced WNK4, as well as an ability of insulin to induce NCC stimulatory phosphorylation in vitro. Together, these findings indicate that hyperinsulinaemia is an important driving force of NCC activity in the metabolic syndrome with possible consequences for BP regulation.

scholarly journals Two Quenchers Formed During Photodamage of Phostosystem II and The Role of One Quencher in Preemptive Photoprotection

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Alonso Zavafer ◽  
Ievgeniia Iermak ◽  
Mun Hon Cheah ◽  
Wah Soon Chow
Keyword(s):  
Chlorophyll Fluorescence ◽  
Photosystem Ii ◽  
Time Course ◽  
Physiological Role ◽  
Reaction Centre ◽  
Time Resolved ◽  
Fluorescence Quencher

AbstractThe quenching of chlorophyll fluorescence caused by photodamage of Photosystem II (qI) is a well recognized phenomenon, where the nature and physiological role of which are still debatable. Paradoxically, photodamage to the reaction centre of Photosystem II is supposed to be alleviated by excitation quenching mechanisms which manifest as fluorescence quenchers. Here we investigated the time course of PSII photodamage in vivo and in vitro and that of picosecond time-resolved chlorophyll fluorescence (quencher formation). Two long-lived fluorescence quenching processes during photodamage were observed and were formed at different speeds. The slow-developing quenching process exhibited a time course similar to that of the accumulation of photodamaged PSII, while the fast-developing process took place faster than the light-induced PSII damage. We attribute the slow process to the accumulation of photodamaged PSII and the fast process to an independent quenching mechanism that precedes PSII photodamage and that alleviates the inactivation of the PSII reaction centre.

Serum interspecies differences in metabolic pathways of bradykinin and [des-Arg9]BK: influence of enalaprilat

1996 ◽  
Vol 271 (4) ◽  
pp. H1340-H1347 ◽  
Author(s):  
A. Decarie ◽  
P. Raymond ◽  
N. Gervais ◽  
R. Couture ◽  
A. Adam
Keyword(s):  
Metabolic Pathways ◽  
Neutral Endopeptidase ◽  
Thrombin Inhibitor ◽  
Rat Serum ◽  
Highly Sensitive ◽  
Significant Difference ◽  
Hydrolysis Of

Among the different enzymes responsible for the metabolism of bradykinin (BK), three peptidases look relevant in vivo: kininase I (KI), which transforms BK into its active metabolite, [des-Arg9]BK; kininase II (KII); and neutral endopeptidase, which inactivate BK and [des-Arg9]BK. The in vitro incubation of BK and [des-Arg9]BK in the serum of four species with or without enalaprilat and the quantification of the immunoreactivity of both peptides at different time intervals allowed the measurement of the kinetic parameters characterizing their metabolic pathways. Highly sensitive chemiluminescent enzyme immunoassays were used to measure the residual concentrations of BK and [des-Arg9]BK. Half-life (t1/2) of BK showed significant difference among species: rats (10 +/- 1 s) = dogs (13 +/- 1 s) < rabbits (31 +/- 1 s) < humans (49 +/- 2 s). t1/2 values of [des-Arg9]BK were also species dependent: rats (96 +/- 6 s) < < rabbits (314 +/- 6 s) = dogs (323 +/- 11 s) = humans (325 +/- 12 s). Enalaprilat significantly prevented the rapid BK and [des-Arg9]BK degradation in all species except that of [des-Arg9]BK in rat serum. Relative amount of BK hydrolyzed by serum KII was given as follows: rabbits (93.7 +/- 14.8%) = rats (83.6 +/- 6.7%) = humans (76.0 +/- 7.5%) > dogs (50.0 +/- 3.9%). Its importance in the hydrolysis of [des-Arg9]BK was 5.2 +/- 0.5% in rats < < 33.9 +/- 1.5% in humans < 52.0 +/- 1.1% in rabbits < 65.1 +/- 3.4% in dogs. The participation of serum KI in the transformation of BK into [des-Arg9]BK was dogs (67.2 +/- 5.3%) > > humans (3.4 +/- 1.2%) = rabbits (1.8 +/- 0.2%) = rats (1.4 +/- 0.3%). Finally, no significant difference on t1/2 values for BK and [des-Arg9]BK could be demonstrated between serum and plasma treated with either sodium citrate or a thrombin inhibitor. These results revealed striking species differences in the serum metabolism of kinins that could address at least partially some of the controversial data related to the cardioprotective role of kinins.

Role of kallikrein-kininogen system in insulin-stimulated glucose transport after muscle contractions

2002 ◽  
Vol 92 (2) ◽  
pp. 657-664 ◽  
Author(s):  
C. L. Dumke ◽  
J. Kim ◽  
E. B. Arias ◽  
G. D. Cartee
Keyword(s):  
Glucose Transport ◽  
Serum Proteins ◽  
Muscle Contractions ◽  
Rat Serum ◽  
Serum Free ◽  
Bradykinin Receptor ◽  
Contraction Effect ◽  
Kallikrein Inhibitors

Serum proteins [molecular weight (MW) > 10,000] are essential for increased insulin-stimulated glucose transport after in vitro muscle contractions. We investigated the role of the kallikrein-kininogen system, including bradykinin, which is derived from kallikrein (MW > 10,000)-catalyzed degradation of serum protein kininogen (MW > 10,000), on this contraction effect. In vitro electrical stimulation of rat epitrochlearis muscles was performed in 1) rat serum ± kallikrein inhibitors; 2) human plasma (normal or kallikrein-deficient); 3) rat serum ± bradykinin receptor-2 inhibitors; or 4) serum-free buffer ± bradykinin. 3- O-methylglucose transport (3-MGT) was measured 3.5 h later. Serum ± kallikrein inhibitors tended ( P = 0.08) to diminish postcontraction insulin-stimulated 3-MGT. Contractions in normal plasma enhanced insulin-stimulated 3-MGT vs. controls, but contractions in kallikrein-deficient plasma did not. Supplementing rat serum with bradykinin receptor antagonist HOE-140 during contraction did not alter insulin-stimulated 3-MGT. Muscles stimulated to contract in serum-free buffer plus bradykinin did not have enhanced insulin-stimulated 3-MGT. Bradykinin was insufficient for postcontraction-enhanced insulin sensitivity. However, results with kallikrein inhibitors and kallikrein-deficient plasma suggest kallikrein plays a role in this improved insulin action.

scholarly journals The mechanism of MinD stability modulation by MinE in Min protein dynamics

2021 ◽  
Author(s):  
William C Carlquist ◽  
Eric N Cytrynbaum
Keyword(s):  
Time Course ◽  
Time Lapse ◽  
Membrane Stability ◽  
The Novel ◽  
Dynamic Interactions ◽  
Asymmetric Activation ◽  
Novel Model

The patterns formed both in vivo and in vitro by the Min protein system have attracted much interest because of the complexity of their dynamic interactions given the apparent simplicity of the component parts. Despite both the experimental and theoretical attention paid to this system, the details of the biochemical interactions of MinD and MinE, the proteins responsible for the patterning, are still unclear. For example, no model consistent with the known biochemistry has yet accounted for the observed dual role of MinE in the membrane stability of MinD. Until now, a statistical comparison of models to the time course of Min protein concentrations on the membrane has not been carried out. Such an approach is a powerful way to test existing and novel models that are difficult to test using a purely experimental approach. Here, we extract time series from previously published fluorescence microscopy time lapse images of in vitro experiments and fit two previously described and one novel mathematical model to the data. We find that the novel model, which we call the Asymmetric Activation with Bridged Stability Model, fits the time-course data best. It is also consistent with known biochemistry and explains the dual MinE role via MinE-dependent membrane stability that transitions under the influence of rising MinE to membrane instability with positive feedback. Our results reveal a more complex network of interactions between MinD and MinE underlying Min-system dynamics than previously considered.

scholarly journals Contribution of progesterone, follicle stimulating hormone and glucocorticoids in survival of serum-free cultured granulosa cell explants

2001 ◽  
Vol 169 (2) ◽  
pp. 321-331 ◽  
Author(s):  
S Mussche ◽  
K D'Herde
Keyword(s):  
Granulosa Cell ◽  
Fold Increase ◽  
Substantial Evidence ◽  
Dapi Staining ◽  
Serum Free ◽  
Survival Factor ◽  
Survival Pathways

To investigate the role of progesterone (P4) as a survival factor in quail granulosa cell explants, P4 content was determined under various conditions and correlated with apoptotic indexes (AIs) evaluated by 2',6'-diamidino-2-phenylindole (DAPI)-staining. Analysis of serum-free cultures from 24 to 96 h shows decreased P4 levels in the medium paralleled by increasing AI. Inhibiting apoptosis by gonadotropic support (FSH, 100 ng/ml) stimulates a 3-fold increase of the P4 level in the medium (83.49+/-8.69 vs 26.31+/-1.61 ng/ml in serum-free controls) together with a significant decrease in AI from 8.81+/-1.06% in serum-free controls to 3.50+/-0.72%. Substantial evidence for P4 as an autocrine/paracrine survival factor can be inferred from experiments with aminoglutethimide (AG, 1 mM) and RU486 (20 microM). Blocking P4 synthesis by AG causes a 2-fold increase in apoptosis from 6.08+/-0.67% in serum-free controls to 12.53+/-1.60%. Blocking P4 receptors by RU486 causes a similar increase in AI (3.02+/-0.98% in serum-free controls to 17.07+/-3.20%) and about a 50% decrease in P4. The effect of RU486 could be attenuated by exogenous P4 but not by dexamethasone indicating selective binding of P4 to the progesterone receptor. Dexamethasone treatment promotes survival without affecting P4 levels. In further support of an autocrine/paracrine action for P4 in the granulosa cells, both the A and B form of the avian P4 receptor (PR) are identified in vivo and in vitro by Western blotting. Exogenous administration of P4 only affects survival when endogenous P4 synthesis is blocked or after 48 h of serum-free culture when endogenous P4 production is very low. Because FSH also affects survival when its stimulatory effect on P4 synthesis is blocked by AG (AI decrease from 6.08+/-0.67% in serum-free controls to 1.64+/-0.71% in FSH+AG treated) it is proposed that (1) P4 is an autocrine/paracrine survival factor in the preovulatory granulosa and (2) FSH mediates both P4-dependent and P4-independent survival pathways.

scholarly journals WASP-interacting Protein Is Important for Actin Filament Elongation and Prompt Pseudopod Formation in Response to a Dynamic Chemoattractant Gradient

2006 ◽  
Vol 17 (10) ◽  
pp. 4564-4575 ◽  
Author(s):  
Scott A. Myers ◽  
Laura R. Leeper ◽  
Chang Y. Chung
Keyword(s):  
Actin Polymerization ◽  
Time Course ◽  
Leading Edge ◽  
Delayed Response ◽  
Dependent Manner ◽  
Actin Assembly ◽  
Interacting Protein

The role of WASP-interacting protein (WIP) in the process of F-actin assembly during chemotaxis of Dictyostelium was examined. Mutations of the WH1 domain of WASP led to a reduction in binding to WIPa, a newly identified homolog of mammalian WIP, a reduction of F-actin polymerization at the leading edge, and a reduction in chemotactic efficiency. WIPa localizes to sites of new pseudopod protrusion and colocalizes with WASP at the leading edge. WIPa increases F-actin elongation in vivo and in vitro in a WASP-dependent manner. WIPa translocates to the cortical membrane upon uniform cAMP stimulation in a time course that parallels F-actin polymerization. WIPa-overexpressing cells exhibit multiple microspike formation and defects in chemotactic efficiency due to frequent changes of direction. Reduced expression of WIPa by expressing a hairpin WIPa (hp WIPa) construct resulted in more polarized cells that exhibit a delayed response to a new chemoattractant source due to delayed extension of pseudopod toward the new gradient. These results suggest that WIPa is required for new pseudopod protrusion and prompt reorientation of cells toward a new gradient by initiating localized bursts of actin polymerization and/or elongation.

scholarly journals The Respiratory Burst Oxidase Homolog Protein D (GhRbohD) Positively Regulates the Cotton Resistance to Verticillium dahliae

2021 ◽  
Vol 22 (23) ◽  
pp. 13041
Author(s):  
Wanting Huang ◽  
Yalin Zhang ◽  
Jinglong Zhou ◽  
Feng Wei ◽  
Zili Feng ◽  
...  
Keyword(s):  
Verticillium Wilt ◽  
Verticillium Dahliae ◽  
Time Course ◽  
Ros Production ◽  
Yield And Quality ◽  
Respiratory Burst Oxidase

Verticillium wilt, mainly caused by a soil-inhabiting fungus Verticillium dahliae, can seriously reduce the yield and quality of cotton. The complex mechanism underlying cotton resistance to Verticillium wilt remains largely unknown. In plants, reactive oxygen species (ROS) mediated by Rbohs is one of the earliest responses of plants to biotic and abiotic stresses. In our previous study, we performed a time-course phospho-proteomic analysis of roots of resistant and susceptible cotton varieties in response to V. dahliae, and found early differentially expressed protein burst oxidase homolog protein D (GhRbohD). However, the role of GhRbohD-mediated ROS in cotton defense against V. dahliae needs further investigation. In this study, we analyzed the function of GhRbohD-mediated resistance of cotton against V. dahliae in vitro and in vivo. Bioinformatics analysis showed that GhRbohD possessed the conservative structural attributes of Rbohs family, 12 members of RbohD out of 57 Rbohs in cotton. The expression of GhRbohD was significantly upregulated after V. dahliae inoculation, peaking at 6 hpi, and the phosphorylation level was also increased. A VIGS test demonstrated that ROS production, NO, H2O2 and Ca2+ contents of GhRbohD-silenced cotton plants were significantly reduced, and lignin synthesis and callose accumulation were damaged, important reasons for the impairment of GhRbohD-silenced cotton’s defense against V. dahliae. The expression levels of resistance-related genes were downregulated in GhRbohD-silenced cotton by qRT-PCR, mainly involving the lignin metabolism pathway and the jasmonic acid signaling pathway. However, overexpression of GhRbohD enhanced resistance of transgenic Arabidopsis to V. dahliae challenge. Furthermore, Y2H assays were applied to find that GhPBL9 and GhRPL12C may interact with GhRbohD. These results strongly support that GhRbohD activates ROS production to positively regulate the resistance of plants against V. dahliae.

scholarly journals Biosynthesis of Rat serum albumin

1971 ◽  
Vol 123 (4) ◽  
pp. 649-655 ◽  
Author(s):  
J. D. Judah ◽  
Marion R. Nicholls
Keyword(s):  
Amino Acid ◽  
Serum Albumin ◽  
Time Course ◽  
Time Lag ◽  
Rat Serum ◽  
Albumin Content ◽  
Double Label ◽  
Rat Serum Albumin

1. The labelling of intracellular and extracellular serum albumin was studied in liver slices and in whole rats by using new methods for the purification of the protein. 2. The results suggest that a polypeptide precursor is formed that is converted relatively slowly into serum albumin. 3. The effect of liver cell K+has been examined by a double-label method and it is shown that K+accelerates the rate of conversion of ‘precursor’ into albumin. The rate of transit of albumin across the cell membrane appears to be unrelated to the concentration of K+within the cell. 4. The time-course of incorporation of radioactive amino acid into albumin follows a sigmoidal mode. There is a pronounced time-lag before label starts to appear in intracellular albumin, and a further time-lag before it appears in extracellular albumin. 5. In slices the sum of intra- and extra-cellular label rises steadily from 30min after the start of labelling with a pulse of labelled leucine or valine and continues to rise for at least another 60min. This occurs whether labelling is stopped by addition of excess of carrier amino acid or with cycloheximide (100μm) or both. 6. The intracellular albumin content remains constant whether slices are maintained with low or normal intracellular K+concentrations. 7. Specific radioactivities of intracellular albumin (and fractions thereof) and of extracellular albumin were determined in vitro and in vivo. The results show that the intracellular albumin cannot be a precursor of extracellular albumin, unless a very small compartment is turning over much more rapidly than the bulk of the liver albumin or even of the microsomal albumin.

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