Cold acclimation-recruited nonshivering thermogenesis: the Syrian hamster is not an exception

1995 ◽  
Vol 269 (4) ◽  
pp. R767-R774 ◽  
Author(s):  
A. Dicker ◽  
B. Cannon ◽  
J. Nedergaard
Keyword(s):  
Metabolic Rate ◽  
Cold Acclimation ◽  
Resting Metabolic Rate ◽  
High Rate ◽  
In Vivo Studies ◽  
Nonshivering Thermogenesis ◽  
Brown Adipose ◽  
Thermogenic Response

Biochemical evidence from in vitro studies of brown adipose tissue in Syrian hamsters indicates a significant degree of recruitment of the tissue as an effect of cold acclimation. However, earlier in vivo studies indicate a lack of recruitment of nonshivering thermogenesis in the intact animal as a result of cold acclimation. Because of this apparent discrepancy, the occurrence of cold acclimation-recruited nonshivering thermogenesis in hamsters was investigated. Hamsters were cold acclimated to 6 degrees C or remained at 24 degrees C (controls), and their thermogenic response was investigated in an open-circuit system at 24 degrees C. Cold acclimation resulted in a small increase in resting metabolic rate and a major increase in the thermogenic response to norepinephrine (61% increase over resting metabolic rate in controls and 156% increase in cold-acclimated animals). The absolute beta 3-specific adrenergic agonist CGP-12177 also induced a high rate of nonshivering thermogenesis, which was similarly recruited. It was concluded that, concerning the relative effect of recruitment on the capacity for nonshivering thermogenesis, the intact hamsters responded as would be predicted from in vitro experiments. Thus the hamster does not seem to constitute an exception to the general patterns described for other rodents concerning recruitment of nonshivering thermogenesis due to cold acclimation.

Blood flow to brown fat in lean and obese adrenalectomized Zucker rats

1986 ◽  
Vol 251 (5) ◽  
pp. R851-R858
Author(s):  
S. J. Wickler ◽  
B. A. Horwitz ◽  
J. S. Stern
Keyword(s):  
Blood Flow ◽  
Weight Gain ◽  
Brown Fat ◽  
Zucker Rats ◽  
Zucker Rat ◽  
Nonshivering Thermogenesis ◽  
Brown Adipose ◽  
Obese Rats

The Zucker obese rat is characterized by decreased capacity for diet-induced and for nonshivering thermogenesis. This decrease is due, in large part, to reduced thermogenesis in depots of brown adipose tissue, a major source of heat production in rats. Adrenalectomy retards the weight gain observed in the obese rats and also normalizes brown fat guanosine 5'-diphosphate (GDP) binding, an in vitro measure of brown fat thermogenic capacity. This study examined the effect of adrenalectomy on brown fat blood flow, an in vivo measure of the tissue's function, and on norepinephrine-induced O2 consumption (NST) of 11-wk-old obese (fa/fa) and lean (Fa/?) rats. Adrenalectomy had little effect on weight gain, NST, or norepinephrine-stimulated blood flow to brown fat in lean rats. However, adrenalectomy produced profound changes in the obese animals, preventing the weight gain normally occurring in the obese rats and normalizing both NST capacity and norepinephrine-stimulated blood flow to brown fat. These findings provide further support for the importance of brown fat thermogenesis and glucocorticoids in modulating the obesity of the Zucker rat.

Effect of norepinephrine and uncoupling agents on brown adipose tissue

1968 ◽  
Vol 46 (6) ◽  
pp. 897-902 ◽  
Author(s):  
Barbara A. Horwitz ◽  
Paul A. Herd ◽  
Robert Emrie Smith
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Brown Fat ◽  
Brown Adipose ◽  
In Vitro Response ◽  
Stimulation Of ◽  
Thermogenic Response

Examination of the in vivo effect of 2,4-dinitrophenol (DNP) on the brown adipose tissue of cold-exposed rats, as well as the in vitro response of this tissue to DNP and dicumarol, indicates that brown fat does possess a functional electron transport coupled phosphorylating system. Moreover, the fact that a norepinephrine-induced thermogenic response (in vivo) can be elicited from the brown fat after DNP administration implies that the effect of norepinephrine (NE) is not primarily due either to a physiological uncoupling by fatty acids, the level of which is increased by NE, or to stimulation of an ATP-ase system. Alternatively, our data suggest that under basal conditions (i.e. when the animal is not stimulated by cold stress or NE), the heat production (oxygen consumption) of the brown fat is limited by the availability of substrate rather than ADP. It is thus proposed that the thermogenic effect of NE results from the stimulation of lipolysis and an attendant increase of substrate available for oxidation.

scholarly journals Anti-Obesity Effects of Microalgae

2019 ◽  
Vol 21 (1) ◽  
pp. 41 ◽  
Author(s):  
Saioa Gómez-Zorita ◽  
Jenifer Trepiana ◽  
Maitane González-Arceo ◽  
Leixuri Aguirre ◽  
Iñaki Milton-Laskibar ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
De Novo ◽  
De Novo Lipogenesis ◽  
In Vivo Studies ◽  
Acid Oxidation ◽  
Low Grade ◽  
Food Ingredients ◽  
Brown Adipose

In recent years, microalgae have attracted great interest for their potential applications in nutraceutical and pharmaceutical industry as an interesting source of bioactive medicinal products and food ingredients with anti-oxidant, anti-inflammatory, anti-cancer, and anti-microbial properties. One potential application for bioactive microalgae compounds is obesity treatment. This review gathers together in vitro and in vivo studies which address the anti-obesity effects of microalgae extracts. The scientific literature supplies evidence supporting an anti-obesity effect of several microalgae: Euglena gracilis, Phaeodactylum tricornutum, Spirulina maxima, Spirulina platensis, or Nitzschia laevis. Regarding the mechanisms of action, microalgae can inhibit pre-adipocyte differentiation and reduce de novo lipogenesis and triglyceride (TG) assembly, thus limiting TG accumulation. Increased lipolysis and fatty acid oxidation can also be observed. Finally, microalgae can induce increased energy expenditure via thermogenesis activation in brown adipose tissue, and browning in white adipose tissue. Along with the reduction in body fat accumulation, other hallmarks of individuals with obesity, such as enhanced plasma lipid levels, insulin resistance, diabetes, or systemic low-grade inflammation are also improved by microalgae treatment. Not only the anti-obesity effect of microalgae but also the improvement of several comorbidities, previously observed in preclinical studies, has been confirmed in clinical trials.

scholarly journals Development of a High-Throughput Biochemical Assay to Screen for Inhibitors of Aerobactin Synthetase IucA

2018 ◽  
Vol 23 (10) ◽  
pp. 1070-1082 ◽  
Author(s):  
Daniel C. Bailey ◽  
Brian P. Buckley ◽  
Mikhail V. Chernov ◽  
Andrew M. Gulick
Keyword(s):  
High Throughput ◽  
Pathogenic Bacteria ◽  
Enzyme Concentration ◽  
High Rate ◽  
Biochemical Assay ◽  
In Vivo Studies ◽  
Nutritional Immunity ◽  
Small Molecule Libraries

Acquiring sufficient quantities of iron to support survival is often a critical limitation for pathogenic bacteria. To meet this demand, bacteria have evolved unique strategies to scavenge iron and circumvent the nutritional immunity exerted by their hosts. One common strategy, which is often a key virulence factor for bacterial pathogens, involves the synthesis, secretion, and reuptake of iron chelators known as siderophores. In vitro and in vivo studies have demonstrated that the siderophore aerobactin is critical for virulence in the hypervirulent pathotype of Klebsiella pneumoniae (hvKP). Given the high rate of multidrug resistance in K. pneumoniae, and in light of the ever-increasing demand for novel Gram-negative therapeutic targets, we identified aerobactin production as a promising antivirulence target in hvKP. Herein, we describe the development of a high-throughput biochemical assay for identifying inhibitors of the aerobactin synthetase IucA. The assay was employed to screen ~110,000 compounds across several commercially available small-molecule libraries. IucA inhibitors with activity at micromolar concentrations were identified in our screening campaigns and confirmed using secondary orthogonal assays. However, the most potent compounds also exhibited some properties commonly observed with promiscuous/nonspecific inhibitors, including incubation time and target enzyme concentration dependence, as well as the potential to antagonize unrelated enzymes.

In vitro and in vivo studies of new cationic Zn(II)‐benzonaphthoporphyrazines as photosensitizers for PDT

2001 ◽  
Vol 5 (8) ◽  
pp. 645-651
Author(s):  
M. Peeva ◽  
M. Shopova ◽  
U. Michelsen ◽  
D. Wöhrle ◽  
G. Petrov ◽  
...  
Keyword(s):  
In Vivo Studies

Effect of caffeine on theophyliine on cerebral blood flow response to brain activation: In vitro and in vivo studies

2005 ◽  
Vol 25 (1_suppl) ◽  
pp. S198-S198
Author(s):  
Joseph R Meno ◽  
Thien-son K Nguyen ◽  
Elise M Jensen ◽  
G Alexander West ◽  
Leonid Groysman ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Brain Activation ◽  
In Vivo Studies ◽  
Blood Flow Response ◽  
Flow Response

Effects of Unfractionated and Low Molecular Weight Heparins on Platelet Thromboxane Biosynthesis “In Vivo”

1994 ◽  
Vol 72 (06) ◽  
pp. 942-946 ◽  
Author(s):  
Raffaele Landolfi ◽  
Erica De Candia ◽  
Bianca Rocca ◽  
Giovanni Ciabattoni ◽  
Armando Antinori ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Unfractionated Heparin ◽  
Low Molecular Weight Heparin ◽  
Primary Source ◽  
In Vivo Studies ◽  
Low Molecular Weight ◽  
Heparin Administration ◽  
To Receive

SummarySeveral “in vitro” and “in vivo” studies indicate that heparin administration may affect platelet function. In this study we investigated the effects of prophylactic heparin on thromboxane (Tx)A2 biosynthesis “in vivo”, as assessed by the urinary excretion of major enzymatic metabolites 11-dehydro-TxB2 and 2,3-dinor-TxB2. Twenty-four patients who were candidates for cholecystectomy because of uncomplicated lithiasis were randomly assigned to receive placebo, unfractionated heparin, low molecular weight heparin or unfractionaed heparin plus 100 mg aspirin. Measurements of daily excretion of Tx metabolites were performed before and during the treatment. In the groups assigned to placebo and to low molecular weight heparin there was no statistically significant modification of Tx metabolite excretion while patients receiving unfractionated heparin had a significant increase of both metabolites (11-dehydro-TxB2: 3844 ± 1388 vs 2092 ±777, p <0.05; 2,3-dinor-TxB2: 2737 ± 808 vs 1535 ± 771 pg/mg creatinine, p <0.05). In patients randomized to receive low-dose aspirin plus unfractionated heparin the excretion of the two metabolites was largely suppressed thus suggesting that platelets are the primary source of enhanced thromboxane biosynthesis associated with heparin administration. These data indicate that unfractionated heparin causes platelet activation “in vivo” and suggest that the use of low molecular weight heparin may avoid this complication.

Effectiveness of the integration of quercetin, turmeric, and N-acetylcysteine in reducing inflammation and pain associated with endometriosis. In-vitro and in-vivo studies

2020 ◽  
Vol 72 (5) ◽  
Author(s):  
Mario Fadin ◽  
Maria C. Nicoletti ◽  
Marzia Pellizzato ◽  
Manuela Accardi ◽  
Maria G. Baietti ◽  
...  
Keyword(s):  
In Vivo Studies
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