Inhibitory effect of curcumin on fatty acid desaturation inMortierella alpina 1S-4 and rat liver microsomes

Lipids ◽  
1992 ◽  
Vol 27 (7) ◽  
pp. 509-512 ◽  
Author(s):  
Sakayu Shimizu ◽  
Saeree Jareonkitmongkol ◽  
Hiroshi Kawashima ◽  
Kengo Akimoto ◽  
Hideaki Yamada
Keyword(s):  
Fatty Acid ◽  
Rat Liver ◽  
Liver Microsomes ◽  
Inhibitory Effect ◽  
Fatty Acid Desaturation ◽  
Rat Liver Microsomes

Autoregulation of 3, 3′,5′-triiodothyronine production by rat liver microsomes

1981 ◽  
Vol 98 (2) ◽  
pp. 240-245 ◽  
Author(s):  
T. Kaminski ◽  
J. Köhrle ◽  
R. Ködding ◽  
R.-D. Hesch
Keyword(s):  
Rat Liver ◽  
Incubation Medium ◽  
Liver Microsomes ◽  
Inhibitory Effect ◽  
Incubation Mixture ◽  
Rat Liver Microsomes ◽  
Experimental Conditions ◽  
Physiological Concentration ◽  
Enzyme Binding ◽  
Ph Dependent

Abstract. Conversion of thyroxine (T4) to 3,3′,5′-triiodothyronine (rT3) was studied in rat liver microsomes. Addition of rT3 at a physiological concentration to the incubation medium inhibited the deiodination of thyroxine to rT3. With a concentration of rT3 greater than 37.6 nM no net rT3 production at pH 8.0 was observed. Further increases in rT3 concentration resulted only in degradation of added rT3 and no net synthesis of rT3 from T4 could be detected. The inhibitory effect of rT3 upon its own production from T4 was pH dependent, 5 fold lower amounts of hormone being required to inhibit completely rT3 production at pH 7.4 than at pH 8.0. With the same experimental conditions no significant effect of rT3 on the conversion of T4 to 3,5,3′-triiodothyronine (T3) could be observed at pH 8.0 with all concentrations of added iodothyronine. A linear production of 3,3′-T2 from added rT3 was determined over the whole range of rT3 concentration, suggesting a lack of saturation of deiodinating enzyme. Binding of rT3 by anti-rT3 antibody added to the incubation mixture enhanced rT3 production from T4 by protecting rT3 from being degraded and/or diminishing the inhibitory effect of this iodothyronine on its own production. It was concluded that rT3 influenced its own production and that this effect may represent an important autoregulatory process in the iodothyronine metabolism.

Inhibitory Effect of Resveratrol on the Pharmacokinetics of Ticagrelor in Vivo and Vitro

2021 ◽  
Author(s):  
Peng Wang ◽  
Xiao-Xia Hu ◽  
Ying-hui Li ◽  
Nan-Yong Gao ◽  
Guo-quan Chen ◽  
...  
Keyword(s):  
Rat Liver ◽  
Liver Microsomes ◽  
In Vitro Study ◽  
Inhibitory Effect ◽  
Control Group ◽  
Rat Liver Microsomes ◽  
Sprague Dawley ◽  
Group B

This study was to evaluate the effect of resveratrol on the pharmacokinetics of ticagrelor in rats and the metabolism of ticagrelor in human CYP3A4 and liver microsomes. Eighteen Sprague-Dawley rats were randomly divided into three groups: group A (control group), group B (50mg/kg resveratrol), and group C (150mg/kg resveratrol ). After 30 minutes administration of resveratrol, a single dose of ticagrelor (18mg/kg) was administered orally. The vitro experiment was performed to examine the influence of resveratrol on ticagrelor metabolism in CYP3A4*1, human, and rat liver microsomes. Serial biological samples were assayed by validated UHPLC-MS/MS methods. In vivo study, the AUC and Cmax of ticagrelor in group B and C appeared to be significantly higher than the control group, while Vz/F and CLz/F of ticagrelor in group B and C were significantly decreased. In vitro study, resveratrol exhibited an inhibitory effect on CYP3A4*1, human and rat liver microsomes. The IC50 values of resveratrol were 56.75μM，69.07μM and 14.22μM, respectively. Our results indicated that resveratrol had a inhibitory effect on the metabolism of ticagrelor in vitro and vivo. It should be paid more attention to the clinical combination of resveratrol with ticagrelor and ticagrelor plasma concentration should be monitored to avoid the occurrence of adverse reaction.

Fluorescence polarization studies of rat liver microsomes with altered phospholipid desaturase activities

1980 ◽  
Vol 58 (10) ◽  
pp. 952-958 ◽  
Author(s):  
E. L. Pugh ◽  
M. Kates ◽  
A. G. Szabo
Keyword(s):  
Fatty Acid ◽  
Rat Liver ◽  
Fluorescence Polarization ◽  
Desaturase Activity ◽  
Liver Microsomes ◽  
Rat Liver Microsomes ◽  
Polarization Ratio ◽  
Parinaric Acid ◽  
Cis And Trans ◽  
Normal Controls

Phospholipid desaturase activity of rat liver microsomes can be varied by dietary manipulation: rats starved and refed a "fat-free" diet have two to three times the activity of normal controls whereas starved rats have no detectable activity. These changes were accompanied by changes in fatty acid composition of the microsomal phospholipids, resulting in a double bond:saturated fatty acid mole ratio (moles double bonds per mole saturated fatty acid) of 5.7 in control and starved rats and 4.7 in starved–refed rats. Fluorescence polarization ratio [Formula: see text] of cis- and trans-parinaric acid (PnA) showed no significant differences in physical state of the three microsomal preparations. However, the isolated microsomal phospholipids with trans-PnA as probe showed differences in the temperature at which onset of a change in polarization ratio occurred (starved–refed > normal > starved rats). With the cis-PnA as probe, the polarization ratio showed no change in the range 10–40 °C but was significantly higher (1.8) in starved–refed rats than in normal and starved rats (1.6 in both cases). These data indicate that the microsomal phospholipids of starved–refed animals were in a less fluid state than those from control and starved rats and that this decrease in fluidity was correlated with an increase in phospholipid desaturase activity.

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