The hemodynamic effects of zymosan in the perfused rat liver

Derbocio, Alice M.; Kelmer-Bracht, Ana Maria; Bracht, Lívia; Bracht, Adelar; Ishii–Iwamoto, Emy Luiza

doi:10.1016/j.vph.2005.05.001

Cited by 6 publications

(13 citation statements)

References 35 publications

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“…This calculation yields a reduction of 37.5% in the rate of metabolic transformation in the presence of zymosan. This is in agreement with our previous observation that zymosan reduces the accessible cellular space [16].…”

Section: Effects Of Zymosan On the Outflow Profiles Of [1-14 C]octanosupporting

confidence: 94%

“…It was suggested that this rapidly exchanging pool represents the plasma membranes and their adjacencies, including the glycocalix and even portions of the endoplasmic reticulum near the cell membrane [21]. The accentuated reduction of this space could be consequence of the zymosaninduced changes in the membrane properties as was also suggested in a previous study in which the action of zymosan on the distribution of tritiated water, urea, and bicarbonate was investigated [16].…”

Section: Discussionmentioning

confidence: 69%

“…Preliminary estimates of , k 3 , k 4 , and k 5 were introduced as well as values of t o and θ , and iteration was continued until minimization of the standard error of the estimate. [16].…”

Section: Data Analysis and Calculationmentioning

confidence: 99%

“…We have further examined the hepatic vascular changes caused by zymosan using the multiple-indicator dilution technique [16]. The data revealed that the vasoconstrictive effect of zymosan results from a constriction of sinusoids of the perivenous zone, producing a distention of the sinusoids of the periportal zone as indicated by the increase in extracellular space of the indicator sucrose.…”

Section: Introductionmentioning

confidence: 99%

“…We have earlier demonstrated that a substantial fraction of exogenously added octanoate is metabolized during a single passage through liver [21], allowing the evaluation of the relationships between parameters of distribution, transport, and intracellular metabolic sequestration in the intact perfused rat liver [17,21]. For this reason, in the present work, we have used the medium chain fatty acid octanoate with the purpose of examining how the liver vascular changes caused by zymosan [16] can affect the hepatic metabolism of exogenous fatty acids. Analysis of the experiments was performed in accordance with the space-distributed variable transit time model proposed by Goresky [17] and Ferraresi-Filho et al [21].…”

Section: Introductionmentioning

confidence: 99%

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The action of zymosan on octanoate transport and metabolism in the isolated perfused rat liver

Derbocio

López

Bracht

et al. 2009

J Biochem & Molecular Tox

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The effects of zymosan on transport, distribution, and metabolism of octanoate in the perfused rat liver were investigated using the multiple-indicator dilution technique. Livers were perfused with 300 microM octanoate in the absence or in the presence of 100 microg/mL zymosan. Tracer amounts of [1-14C]octanoate, [3H] water, and [131I]albumin were injected into the portal vein, and the effluent perfusate was fractionated. The normalized dilution curves were analyzed by means of a space-distributed variable transit time model. Zymosan decreased the space into which octanoate undergoes flow-limited distribution, possibly the first cellular exchanging pool represented by plasma membranes and their adjacencies. However, the rate of transfer of octanoate from the plasma membrane into the rest of the cell was not modified as indicated by the similar values of the influx rates and also the net uptake of octanoate per unit of accessible cellular volume. However, when referred to the wet weight of the liver, the net uptake of octanoate was 37.5% reduced, a value corresponding to the diminution of the cellular accessible space. It can be concluded that an exclusion of a fraction of the liver parenchyma from the microcirculation is the main mechanism by which zymosan reduces the metabolism of exogenous octanoate.

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Section: Effects Of Zymosan On the Outflow Profiles Of [1-14 C]octanosupporting

confidence: 94%

Section: Discussionmentioning

confidence: 69%

Section: Data Analysis and Calculationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The action of zymosan on octanoate transport and metabolism in the isolated perfused rat liver

Derbocio

López

Bracht

et al. 2009

J Biochem & Molecular Tox

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Transformation products of extracellular NAD+ in the rat liver: kinetics of formation and metabolic action

Broetto-Biazon

Bracht²,

Sá‐Nakanishi³

et al. 2007

Mol Cell Biochem

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The perfused rat liver responds in several ways to NAD(+) infusion (20-100 microM). Increases in portal perfusion pressure and glycogenolysis and transient inhibition of oxygen consumption and gluconeogenesis are some of the effects that were observed. Extracellular NAD(+) is also extensively transformed in the liver. The purpose of the present work was to determine the main products of extracellular NAD(+) transformation under various conditions and to investigate the possible contribution of these products for the metabolic effects of the parent compound. The experiments were done with the isolated perfused rat liver. The NAD(+) transformation was monitored by HPLC. Confirming previous findings, the single-pass transformation of 100 microM NAD(+) ranged between 75% at 1.5 min after starting infusion to 95% at 8 min. The most important products of single-pass NAD(+) transformation appearing in the outflowing perfusate were nicotinamide, ADP-ribose, uric acid, and inosine. The relative proportions of these products presented some variations with the time after initiation of NAD(+) infusion and the perfusion conditions, but ADP-ribose was always more abundant than uric acid and inosine. Cyclic ADP-ribose (cADP-ribose) as well as adenosine were not detected in the outflowing perfusate. The metabolic effects of ADP-ribose were essentially those already described for NAD(+). These effects were sensitive to suramin (P2(XY) purinergic receptor antagonist) and insensitive to 3,7-dimethyl-1-(2-propargyl)-xanthine (A2 purinergic receptor antagonist). Inosine, a known purinergic A3 agonist, was also active on metabolism, but uric acid and nicotinamide were inactive. It was concluded that the metabolic and hemodynamic effects of extracellular NAD(+) are caused mainly by interactions with purinergic receptors with a highly significant participation of its main transformation product ADP-ribose.

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Kupffer cell activation in normal and fibrotic livers increases portal pressure via thromboxane A2

Steib

Gerbes

Bystron

et al. 2007

Journal of Hepatology

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The hemodynamic effects of zymosan in the perfused rat liver

Cited by 6 publications

References 35 publications

The action of zymosan on octanoate transport and metabolism in the isolated perfused rat liver

The action of zymosan on octanoate transport and metabolism in the isolated perfused rat liver

Transformation products of extracellular NAD+ in the rat liver: kinetics of formation and metabolic action

Kupffer cell activation in normal and fibrotic livers increases portal pressure via thromboxane A2

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