scholarly journals Independent regulation of 3-hydroxy-3-methylglutaryl-coenzyme A reductase and chylomicron remnant receptor activities in rat liver

1984 ◽  
Vol 218 (1) ◽  
pp. 203-211 ◽  
Author(s):  
D P Wade ◽  
A K Soutar ◽  
G F Gibbons

Treatment of rats with pharmacological doses of oestrogen resulted in a 3-fold decrease in the activity of hepatic 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA reductase) and a 4-fold increase in saturable binding of 125I-labelled chylomicron remnants to liver membranes in vitro. Intragastric administration of mevalonolactone to rats did not affect the capacity of the liver membranes to bind to labelled chylomicron remnants even though there was a substantial decrease in the activity of HMG-CoA reductase. Similar results were obtained after cholesterol feeding. Simultaneous treatment of rats with cholestyramine and compactin increased hepatic HMG-CoA reductase activity 6-fold. However, liver membranes derived from these animals showed no change in their capacity to bind to labelled chylomicron remnants in vitro. Administration of mevalonolactone to the cholestyramine/compactin-treated animals also failed to produce a change in remnant-binding capacity. Although administration of mevalonolactone alone produced a significant 3-fold decrease in the activity of hepatic HMG-CoA reductase it was unable to suppress significantly the increase in enzyme activity caused by treatment with cholestyramine and compactin.

1978 ◽  
Vol 56 (10) ◽  
pp. 958-962 ◽  
Author(s):  
B. Preiss ◽  
L. Tan ◽  
J.-G. Lehoux

3-Hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase) activity (mevalonate:NADP+ oxidoreductase (CoA-acylating) EC 1.1.1.34) was demonstrated in beef adrenal cortex. Most of the HMG-CoA reductase activity is in the microsomal fraction while a small percentage of the activity is associated with the mitochondria, Mitochondria purified on a linear sucrose gradient are enriched in HMG-CoA reductase and cytochrome c oxidase activities. The reductase present in microsomal preparations from the whole adrenal cortex has an apparent Km of 5.6 × 10−5 M for (R,S)-HMG-CoA. Reductase activities found in the microsomal fractions from the zona glomerulosa, the zona fasciculata, and the zona reticularis were 1.32, 7.37, and 9.74 nmol mevalonate formed per milligram protein in 30 min respectively.


1977 ◽  
Vol 164 (3) ◽  
pp. 501-508 ◽  
Author(s):  
Y A Baqir ◽  
R Booth

A new method suitable for measuring rat liver 3-hydroxy-3-methylglutaryl-CoA reductase activity is described and its advantages over methods previously available are discussed. An accurate time course was measured for the inhibition of liver microsomal 3-hydroxy-3-methylglutaryl-CoA reductase activity by dietary cholesterol; this enzyme was affected 1 1/4 h after the rats began to consume a cholesterol-rich diet. In this experiment there was no correlation between concentrations of microsomal cholesterol ester and the activity of 3-hydroxy-3-methylglutary-CoA reductase.


2017 ◽  
Vol 5 (14) ◽  
Author(s):  
Hiroya Itoh ◽  
Makoto Matsui ◽  
Toshitaka Kumagai ◽  
Masanori Arita ◽  
Masayuki Machida ◽  
...  

ABSTRACT Fungal strain 14919 was originally isolated from a soil sample collected at Mt. Kiyosumi, Chiba Prefecture, Japan. It produces FR901512, a potent and strong 3-hydroxy-3-methylglutaryl–coenzyme A (HMG-CoA) reductase inhibitor. The genome sequence of fungal strain 14919 was determined and annotated to improve the productivity of FR901512.


2021 ◽  
Vol 5 ◽  
Author(s):  
H. P. Mohankumari ◽  
K. Akhilender Naidu ◽  
K. Narasimhamurthy ◽  
G. Vijayalakshmi

Monascus purpureus is known to produce pigment molecules. The pigments were extracted from M. purpureus fermented rice. In-vitro antioxidant effects of pigments were observed and presumed to alleviate oxidative stress related atherosclerosis effect in rats fed with high fat diet (HFD) for 14 weeks. The formation of lipid peroxide due to the oxidation of serum lipid was higher in rats fed with HFD. While, the feeding of fermented rice (groups III-V) significantly lowered the formation of lipid peroxide (27.1–51.7%) in serum of rats, indicated antioxidative effect of pigments. In addition, feeding of fermented rice lowered serum cholesterol and triacylglycerol by 44.82 and 45.30%, respectively. Whereas, LDL-cholesterol levels were decreased by 70.12% and HDL-cholesterol increased by 34.58%. The atherogenic indices (LDL/HDL and TC/HDL) were reduced by 77.80 and 61.05%, respectively, in rats fed with fermented rice. These data confirmed the anti-atherosclerotic effect of pigments. Further liver enzyme, 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase activity was significantly inhibited up to 54%. The identification of statins, sterols and fatty acids in fermented rice revealed the HMG-CoA reductase inhibitory activity. This was confirmed by synthesis of lower levels of cholesterol and triacylglycerol in liver of rats fed with fermented rice. Accordingly antioxidant, inhibition of HMG-CoA reductase, anti-atherogenic functions of M. purpureus fermented rice is attributed to the collective effect of bioactive metabolites.


Blood ◽  
1991 ◽  
Vol 77 (5) ◽  
pp. 1064-1070 ◽  
Author(s):  
RJ Hohl ◽  
RA Larson ◽  
V Mannickarottu ◽  
S Yachnin

Abstract The effects of competitive inhibition of hydroxymethylglutaryl coenzyme A (HMG CoA) reductase by compactin on the in vitro proliferation of peripheral blood myeloid leukemia cells were studied using the cells from 45 patients with acute myeloid leukemia or chronic myelogenous leukemia in blast phase. The cells from 58% of these patients showed a dose-related inhibition of DNA synthesis when incubated with compactin. Unexpectedly, cells from 18% of the patients were resistant to the inhibitory effects of compactin on DNA synthesis and responded to the HMG CoA reductase inhibition with an actual increase in the incorporation of 14C-labeled thymidine into DNA. Another 18% of the patients studied displayed both inhibition and stimulation of DNA synthesis in a biphasic response depending on the particular concentration of compactin used. The maximum enhanced rates of cellular DNA synthesis were observed with lower compactin concentrations (5 x 10(-7) mol/L) than were required for maximum inhibition of DNA synthesis (10(-5) mol/L). Leukemia cells displaying a stimulated response to compactin had a significantly lower baseline DNA synthetic rate than did cells that showed an inhibitory response of DNA synthesis to compactin. There was no correlation between these cells' varying DNA synthetic response to compactin and measures of baseline HMG CoA reductase activity or acetate conversion to cholesterol. Whereas the observation of cellular DNA synthesis stimulation by HMG CoA reductase inhibition has not been observed in other mammalian cells and seems paradoxical, explanations may emerge in light of our growing knowledge concerning the importance of isoprenylation for the function of certain cell regulatory proteins.


1976 ◽  
Vol 154 (2) ◽  
pp. 559-560 ◽  
Author(s):  
M M. Sudjic ◽  
R Booth

Rat brain contains 3-hydroxy-3-methylglutaryl-CoA reductase activity, but this enzyme is far more active in 7-day-old brain than in adult brain. This difference may partly explain why cholesterol biosynthesis is more rapid in growing than in adult rat brain.


2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Fei Xu ◽  
Hui Yu ◽  
Cai Lu ◽  
Jun Chen ◽  
Wei Gu

This study measured the impact of alisol B 23-acetate and alisol A 24-acetate, the main active ingredients of the traditional Chinese medicine Alismatis rhizoma, on total cholesterol (TC), triglyceride (TG), high density lipoprotein-cholesterol (HDL-C), and low density lipoprotein-cholesterol (LDL-C) levels of hyperlipidemic mice. The binding of alisol B 23-acetate and alisol A 24-acetate to the key enzyme involved in the metabolism of TC, 3-hydroxy-3-methylglutary-coenzyme A (HMG-CoA) reductase, was studied using the reagent kit method and the western blotting technique combined with a molecular simulation technique. According to the results, alisol acetates significantly lower the TC, TG, and LDL-C concentrations of hyperlipidemic mice, while raising HDL-C concentrations. Alisol acetates lower HMG-CoA reductase activity in a dose-dependent fashion, both in vivo and in vitro. Neither of these alisol acetates significantly lower the protein expression of HMG-CoA. This suggests that alisol acetates lower the TC level via inhibiting the activity of HMG-CoA reductase by its prototype drug, which may exhibit an inhibition effect via directly and competitively binding to HMG-CoA. The side chain of the alisol acetate was the steering group via molecular simulation.


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