scholarly journals Hemin attenuates response of primary rat adipocytes to adrenergic stimulation

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12092
Author(s):  
Tomasz Szkudelski ◽  
Karina Frąckowiak ◽  
Katarzyna Szkudelska
Keyword(s):  
Inhibitory Effect ◽  
Heme Oxygenase 1 ◽  
Adrenergic Stimulation ◽  
Inhibitory Effects ◽  
Short Term ◽  
Isolated Cells ◽  
Lactate Release ◽  
Rat Adipocytes ◽  
Beneficial Effects ◽  
Short Term Exposure

Hemin is an activator of heme oxygenase-1 (HO-1), an enzyme catalyzing heme degradation. Up-regulation of HO-1 is observed in response to various pathological conditions. Moreover, pharmacological activation of HO-1 is associated with numerous beneficial effects in the organism. Hemin was shown to exert, among other, anti-diabetic and anti-obesity properties. These effects are strongly linked with adipose tissue. However, the direct influence of hemin on metabolism of the fat cells have not been explored. The present study aimed to determine the short-term effects of hemin on metabolism of the primary rat adipocytes. We focused on processes directly related to lipid accumulation, such as lipogenesis and lipolysis. For this purpose, the isolated cells were subjected for 2 h to 40 µM hemin, and effects of this compound on insulin-stimulated glucose conversion to lipids, lactate release, lipolysis induced by various stimuli, and also on the antilipolytic action of insulin were determined. It was shown that hemin did not affect insulin-induced lipogenesis and lactate release. However, hemin significantly decreased lipolysis stimulated by epinephrine. The inhibitory effect of hemin on epinephrine-induced lipolysis was not abolished in the presence of SnMP, an inhibitor of HO-1, which suggests hemin action irrespective of this enzyme. Similar inhibitory effects on epinephrine-induced lipolysis were observed in the presence of 3 and 12 mM glucose. Moreover, hemin was shown to reduce epinephrine-induced lipolysis also when glucose was replaced by alanine or by succinate. Apart from changes in epinephrine action, it was found that the lipolytic response of the adipocytes to isoproterenol was also diminished by hemin. However, hemin failed to affect lipolysis stimulated by dibutyryl-cAMP (a direct activator of protein kinase A), forskolin (an activator of adenylate cyclase), and also by DPCPX (an adenosine A1 receptor antagonist). Additionally, epinephrine-induced lipolysis was shown to be decreased by insulin, and this effect was deepened in the presence of hemin. These results indicate that short-term exposure of the adipocytes to hemin does not affect processes related to glucose metabolism, such as lipogenesis and lactate release. However, hemin was found to decrease the lipolytic response to adrenergic stimulation, which is associated with reduced lipid release from adipocytes. Moreover, our results indicate that hemin is also capable of diminishing the exaggerated lipolysis, which occurs in the presence of supraphysiological concentrations of glucose.

The Effect of High Concentrations of Ethylene on Seed Germination of Douglas Fir (Pseudotsugamenziesii (Mirb.) Franco)

1975 ◽  
Vol 5 (3) ◽  
pp. 419-423 ◽  
Author(s):  
Carey Borno ◽  
Iain E. P. Taylor
Keyword(s):  
Seed Germination ◽  
Germination Rate ◽  
Inhibitory Effect ◽  
Germination Percentage ◽  
Douglas Fir ◽  
Control Treatment ◽  
Continuous Exposure ◽  
Short Term ◽  
Short Term Exposure ◽  
High Concentrations

Stratified, imbibed Douglas fir (Pseudotsugamenziesii (Mirb.) Franco) seeds were exposed to 100% ethylene for times between 0 and 366 h. Germination rate and germination percentage were increased by treatments up to 48 h. The 12-h treatment gave largest stimulation; 30% enhancement of final germination percentage over control. Treatment for 96 h caused increased germination rate for the first 5 days but reduced the germination percentage. Germinants were subject to continuous exposure to atmospheres containing 0.1 – 200 000 ppm ethylene in air, but it did not stimulate growth, and the gas was inhibitory above 100 ppm. Although some effects of high concentrations of ethylene may have been due to the lowering of oxygen supplies, this alone was insufficient to account for the full inhibitory effect. The mechanism of stimulation by short-term exposure to ethylene is discussed.

scholarly journals Short-Term and Long-Term Inhibitory Effects of Copper on Anammox Process

Proceedings ◽  
2018 ◽  
Vol 2 (11) ◽  
pp. 657 ◽  
Author(s):  
Cigdem Kalkan Aktan ◽  
Ayse Ekin Uzunhasanoglu ◽  
Kozet Yapsakli ◽  
Bulent Mertoglu
Keyword(s):  
Competitive Inhibition ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Anammox Bacteria ◽  
Inhibitory Effects ◽  
Short Term ◽  
Inhibition Model ◽  
Short Term Exposure ◽  
Anammox Process

The main goal of this study is to evaluate the short-term and long-term inhibitory effects of Cu (II) on Anammox process. To investigate the short-term inhibition level, four different concentrations (1, 2.5, 5 and 10 mg L−1 as Cu2+) were tested in batch reactors. IC50 levels for short-term exposure deduced as 4.57mg L−1 (R2: 0.97) from the modified non-competitive inhibition model. Lab-scale continuous flow up-flow fixed bed reactor with Kaldness biofilm carriers was operated 240 days with gradually increased Cu concentrations (from 0.2 to 8 mg L−1). To identify the IC50 levels in case of prolonged exposure of Cu(II), experimental data were fitted with a modified non-competitive inhibition model, and calculated as 6.77 mg L−1 (R2: 0.95). The results show that the IC50 level for copper in long-term exposure was higher than in short-term exposure and the possible reason for that is the self-adaptation of Anammox bacteria.

scholarly journals The effects of 3-amino-1,2,4-triazole on the growth of sporelings of marine red Algae

1963 ◽  
Vol 43 (3) ◽  
pp. 643-652 ◽  
Author(s):  
A. D. Boney
Keyword(s):  
Red Algae ◽  
Culture Medium ◽  
Inhibitory Effect ◽  
Inhibitory Effects ◽  
Growth Inhibitory Effect ◽  
Short Term ◽  
Cell Production ◽  
Lasting Effect ◽  
Growth Inhibitory

The cell production of sporelings of five species of marine red algae is inhibited by 3-amino-i,2,4-triazole (3AT).Results show that short-term immersions in culture medium containing 3AT have a lasting effect on the growth of sporelingsThis growth inhibitory effect is reversed by addition of adenine.Protracted contact with 3AT results in some chlorosis of the sporelingThe growth inhibitory effects of 3AT are more marked with sporelings of intertidal red algae than with sublittoral species.

scholarly journals Bisphenol A disturbs metabolism of primary rat adipocytes without affecting adipokine secretion

2021 ◽  
Author(s):  
Katarzyna Szkudelska ◽  
Monika Okulicz ◽  
Tomasz Szkudelski
Keyword(s):  
Bisphenol A ◽  
Glucose Oxidation ◽  
Low Doses ◽  
Dibutyryl Camp ◽  
Short Term ◽  
Rat Adipocytes ◽  
Short Term Exposure ◽  
Kinase A ◽  
Isolated Rat ◽  
Direct Activator

AbstractBisphenol A (BPA) is an ubiquitous synthetic chemical exerting numerous adverse effects. Results of rodent studies show that BPA negatively affects adipose tissue. However, the short-term influence of this compound addressing adipocyte metabolism and adipokine secretion is unknown. In the present study, isolated rat adipocytes were exposed for 2 h to 1 and 10 nM BPA. Insulin-induced glucose conversion to lipids along with glucose transport was significantly increased in the presence of BPA. However, basal glucose conversion to lipids, glucose oxidation, and formation of lipids from acetate were unchanged in adipocytes incubated with BPA. It was also shown that BPA significantly increases lipolytic response of adipocytes to epinephrine. However, lipolysis stimulated by dibutyryl-cAMP (a direct activator of protein kinase A) and the antilipolytic action of insulin were not affected by BPA. Moreover, BPA did not influence leptin and adiponectin secretion from adipocytes. Our new results show that BPA is capable of disturbing processes related to lipid accumulation in isolated rat adipocytes. This is associated with the potentiation of insulin and epinephrine action. The effects of BPA appear already after short-term exposure to low doses of this compound. However, BPA fails to change adipokine secretion.

In Vitro Effects of Ethanol on Rabbit Platelet Aggregation, Secretion of Granule Contents, and Cyclic AMP Levels in the Presence of Prostacyclin

1989 ◽  
Vol 61 (02) ◽  
pp. 254-258 ◽  
Author(s):  
Margaret L Rand ◽  
Peter L Gross ◽  
Donna M Jakowec ◽  
Marian A Packham ◽  
J Fraser Mustard
Keyword(s):  
Cyclic Amp ◽  
Inhibitory Effect ◽  
Rabbit Platelet ◽  
Inhibitory Effects ◽  
Low Concentrations ◽  
Rabbit Platelets ◽  
High Concentrations ◽  
In Vitro Effects ◽  
Aggregation Of Platelets

SummaryEthanol, at physiologically tolerable concentrations, inhibits platelet responses to low concentrations of collagen or thrombin, but does not inhibit responses of washed rabbit platelets stimulated with high concentrations of ADP, collagen, or thrombin. However, when platelet responses to high concentrations of collagen or thrombin had been partially inhibited by prostacyclin (PGI2), ethanol had additional inhibitory effects on aggregation and secretion. These effects were also observed with aspirin- treated platelets stimulated with thrombin. Ethanol had no further inhibitory effect on aggregation of platelets stimulated with ADP, or the combination of ADP and epinephrine. Thus, the inhibitory effects of ethanol on platelet responses in the presence of PGI2 were very similar to its inhibitory effects in the absence of PGI2, when platelets were stimulated with lower concentrations of collagen or thrombin. Ethanol did not appear to exert its inhibitory effects by increasing cyclic AMP above basal levels and the additional inhibitory effects of ethanol in the presence of PGI2 did not appear to be brought about by further increases in platelet cyclic AMP levels.

The Effect of Dimethyl Sulfoxide on In Vitro Platelet Function

1976 ◽  
Vol 36 (01) ◽  
pp. 221-229 ◽  
Author(s):  
Charles A. Schiffer ◽  
Caroline L. Whitaker ◽  
Morton Schmukler ◽  
Joseph Aisner ◽  
Steven L. Hilbert
Keyword(s):  
Platelet Count ◽  
Platelet Aggregation ◽  
Dimethyl Sulfoxide ◽  
Platelet Function ◽  
Platelet Volume ◽  
Short Term ◽  
Platelet Factor ◽  
Short Term Exposure ◽  
Structural Abnormalities

SummaryAlthough dimethyl sulfoxide (DMSO) has been used extensively as a cryopreservative for platelets there are few studies dealing with the effect of DMSO on platelet function. Using techniques similar to those employed in platelet cryopreservation platelets were incubated with final concentrations of 2-10% DMSO at 25° C. After exposure to 5 and 10% DMSO platelets remained discoid and electron micrographs revealed no structural abnormalities. There was no significant change in platelet count. In terms of injury to platelet membranes, there was no increased availability of platelet factor-3 or leakage of nucleotides, 5 hydroxytryptamine (5HT) or glycosidases with final DMSO concentrations of 2.5, 5 and 10% DMSO. Thrombin stimulated nucleotide and 5HT release was reduced by 10% DMSO. Impairment of thrombin induced glycosidase release was noted at lower DMSO concentrations and was dose related. Similarly, aggregation to ADP was progressively impaired at DMSO concentrations from 1-5% and was dose related. After the platelets exposed to DMSO were washed, however, aggregation and release returned to control values. Platelet aggregation by epinephrine was also inhibited by DMSO and this could not be corrected by washing the platelets. DMSO-plasma solutions are hypertonic but only minimal increases in platelet volume (at 10% DMSO) could be detected. Shrinkage of platelets was seen with hypertonic solutions of sodium chloride or sucrose suggesting that the rapid transmembrane passage of DMSO prevented significant shifts of water. These studies demonstrate that there are minimal irreversible alterations in in vitro platelet function after short-term exposure to DMSO.

Inhibition of ADP-Induced Responses in Human Platelets by Agents Elevating the Cyclic AMP Level: Comparison of Aggregation and Shape Change

1984 ◽  
Vol 52 (03) ◽  
pp. 333-335 ◽  
Author(s):  
Vider M Steen ◽  
Holm Holmsen
Keyword(s):  
Inhibitory Action ◽  
Human Platelet ◽  
Platelet Rich Plasma ◽  
Shape Change ◽  
Inhibitory Effect ◽  
Human Platelets ◽  
Inhibitory Effects ◽  
Early Step ◽  
Stimulus Response ◽  
Sequential Relationship

SummaryThe inhibitory effect of cAMP-elevating agents on shape change and aggregation in human platelets was studied to improve the understanding of the sequential relationship between these two responses.Human platelet-rich plasma was preincubated for 2 min at 37° C with prostaglandin E1 or adenosine, agents known to elevate the intracellular level of cAMP. Their inhibitory effects on ADP-induced shape change and aggregation were determined both separately and simultaneously. The dose-inhibition patterns for shape change and aggregation were similar for both PGE1 and adenosine. There was no distinct difference between the inhibitory action of these two inhibitors.These observations suggest that elevation of the intracellular concentration of cAMP interferes with an early step in the stimulus-response coupling that is common for aggregation and shape change.

The Inhibitory Effect of Heparin and Related Glycosaminoglycans on Neutrophil Chemotaxis

1984 ◽  
Vol 52 (02) ◽  
pp. 134-137 ◽  
Author(s):  
Yaacov Matzner ◽  
Gerard Marx ◽  
Ruth Drexler ◽  
Amiram Eldor
Keyword(s):  
Specific Binding ◽  
Anticoagulant Activity ◽  
Neutrophil Migration ◽  
Inhibitory Effect ◽  
Chemotactic Factor ◽  
Human Neutrophils ◽  
Boyden Chamber ◽  
Neutrophil Chemotaxis ◽  
Inhibitory Effects ◽  
Chemotactic Factors

SummaryClinical observations have shown that heparin has antiinflammatory activities. The effect of heparin on neutrophil chemotaxis was evaluated in vitro in the Boyden Chamber. This method enabled differentiation between the direct effects of heparin on neutrophil migration and locomotion, and its effects on chemotactic factors. Heparin inhibited both the random migration and directed locomotion of human neutrophils toward zymosan-activated serum (ZAS) and F-met-leu-phe (FMLP). Inhibition was found to be dependent on the concentrations of the heparin and of the chemotactic factors. No specific binding of heparin to the neutrophils could be demonstrated, and heparin’s inhibitory effects were eliminated by simple washing of the cells. When added directly to the chamber containing chemotactic factor, heparin inhibited the chemotactic activity of ZAS but not that of FMLP, suggesting a direct inhibitory effect against C5a, the principal chemotactic factor in ZAS.Experiments performed with low-molecular-weight heparin, N-desulfated heparin, dextran sulfate, chondroitin sulfate and dextran indicated that the inhibitory effects of heparin on neutrophil chemotaxis are not related to its anticoagulant activity, but probably depend on the degree of sulfation of the heparin molecule.

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