Lipids and Δ6-desaturase activity alterations in rat liver microsomal membranes induced by fumonisin B1

Lipids ◽  
2002 ◽  
Vol 37 (9) ◽  
pp. 869-877 ◽  
Author(s):  
W. C. A. Gelderblom ◽  
W. Moritz ◽  
S. Swanevelder ◽  
C. M. Smuts ◽  
S. Abel
Keyword(s):  
Rat Liver ◽  
Desaturase Activity ◽  
Fumonisin B1 ◽  
Microsomal Membranes ◽  
Δ6 Desaturase

Isolation and expression of cDNA clones for a rat liver asialoglycoprotein receptor

1986 ◽  
Vol 6 (6) ◽  
pp. 527-534
Author(s):  
Colin Watts
Keyword(s):  
Rat Liver ◽  
Protein Sequence ◽  
Wheat Germ ◽  
Asialoglycoprotein Receptor ◽  
Cdna Clones ◽  
Oligonucleotide Probes ◽  
Synthetic Oligonucleotide ◽  
Microsomal Membranes ◽  
Synthetic Oligonucleotides

cDNA clones for the major rat liver asialoglycoprotein (ASGP) receptor were isolated from a phage λgtl 1 library using synthetic oligonucleotide probes corresponding to two regions of the protein sequence. The longest clone obtained encoded all but the first 11 codons of the receptor. The cDNA was completed with synthetic oligonucleotides and was used to direct the synthesis of mRNA for the receptor in vitro. Subsequent translation in a wheat germ lysate produced authentic ASGP receptor which assembled correctly into microsomal membranes.

Sex Specific Binding of Steroid Hormones to Microsomal Membranes of Rat Liver

1971 ◽  
Vol 230 (13) ◽  
pp. 137-139 ◽  
Author(s):  
CAROL A. BLYTH ◽  
R. B. FREEDMAN ◽  
B. R. RABIN
Keyword(s):  
Steroid Hormones ◽  
Rat Liver ◽  
Specific Binding ◽  
Microsomal Membranes

scholarly journals Subcellular distribution and characteristics of trihydroxycoprostanoyl-CoA synthetase in rat liver

1989 ◽  
Vol 257 (1) ◽  
pp. 221-229 ◽  
Author(s):  
L Schepers ◽  
M Casteels ◽  
K Verheyden ◽  
G Parmentier ◽  
S Asselberghs ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Cholic Acid ◽  
Rat Liver ◽  
Subcellular Distribution ◽  
The Other ◽  
Acid Activation ◽  
Long Chain Fatty Acids ◽  
Microsomal Membranes ◽  
Triton X ◽  
Long Chain

The subcellular distribution and characteristics of trihydroxycoprostanoyl-CoA synthetase were studied in rat liver and were compared with those of palmitoyl-CoA synthetase and choloyl-CoA synthetase. Trihydroxycoprostanoyl-CoA synthetase and choloyl-CoA synthetase were localized almost completely in the endoplasmic reticulum. A quantitatively insignificant part of trihydroxycoprostanoyl-CoA synthetase was perhaps present in mitochondria. Peroxisomes, which convert trihydroxycoprostanoyl-CoA into choloyl-CoA, were devoid of trihydroxycoprostanoyl-CoA synthetase. As already known, palmitoyl-CoA synthetase was distributed among mitochondria, peroxisomes and endoplasmic reticulum. Substrate- and cofactor- (ATP, CoASH) dependence of the three synthesis activities were also studied. Cholic acid and trihydroxycoprostanic acid did not inhibit palmitoyl-CoA synthetase; palmitate inhibited the other synthetases non-competitively. Likewise, cholic acid inhibited trihydroxycoprostanic acid activation non-competitively and vice versa. The pH curves of the synthetases did not coincide. Triton X-100 affected the activity of each of the synthetases differently. Trihydroxycoprostanoyl-CoA synthetase was less sensitive towards inhibition by pyrophosphate than choloyl-CoA synthetase. The synthetases could not be solubilized from microsomal membranes by treatment with 1 M-NaCl, but could be solubilized with Triton X-100 or Triton X-100 plus NaCl. The detergent-solubilized trihydroxycoprostanoyl-CoA synthetase could be separated from the solubilized choloyl-CoA synthetase and palmitoyl-CoA synthetase by affinity chromatograpy on Sepharose to which trihydroxycoprostanic acid was bound. Choloyl-CoA synthetase and trihydroxycoprostanoyl-CoA synthetase could not be detected in homogenates from kidney or intestinal mucosa. The results indicate that long-chain fatty acids, cholic acid and trihydroxycoprostanic acid are activated by three separate enzymes.

Fractionation of isolated liver cells after disruption with a nitrogen bomb and sonication

1982 ◽  
Vol 57 (1) ◽  
pp. 1-13
Author(s):  
F. Autuori ◽  
U. Brunk ◽  
E. Peterson ◽  
G. Dallner
Keyword(s):  
Rat Liver ◽  
Sucrose Gradient ◽  
Divalent Cations ◽  
Liver Cells ◽  
Cell Disruption ◽  
Isolated Liver Cells ◽  
Discontinuous Sucrose Gradient ◽  
Microsomal Membranes ◽  
Isolated Liver

Hepatocytes from rat liver were prepared by perfusion with collagenase, and rough and smooth microsomes and mitochondria were prepared after cell disruption. By applying 1000 lb/in2 (1 lb/in2 = 6.9 kPa) in a nitrogen bomb followed by decompression, 75% of the cells were disrupted after four consecutive treatments. Intact mitochondria, and rough and smooth microsomes with little contamination were prepared from the homogenate. A more rapid disruption was attained by a short sonication with a low output, thus increasing the efficiency of homogenization. The microsomal subfractions prepared from this homogenate were comparable to those obtained after decompression. Sonication resulted in smooth microsomes, which exhibited a higher contamination with non-microsomal membranes. These, however, were partly removed by additional centrifugation with a discontinuous sucrose gradient containing divalent cations.

Mechanism of Fumonisin Toxicity and Carcinogenesis

1994 ◽  
Vol 57 (7) ◽  
pp. 638-644 ◽  
Author(s):  
RONALD T. RILEY ◽  
KENNETH A. VOSS ◽  
HWAN -SOO YOO ◽  
WENTZEL C.A. GELDERBLOM ◽  
ALFRED H. MERRILL
Keyword(s):  
Rat Liver ◽  
Cell Injury ◽  
Cultured Cells ◽  
Degradation Products ◽  
Fumonisin B1 ◽  
Hepatocyte Proliferation ◽  
Sphingolipid Metabolism ◽  
Sphingoid Base ◽  
Cultured Fibroblasts ◽  
Animal Diseases

What are the molecular events that fumonisin-induced porcine pulmonary edema syndrome and equine leucoencephalomalacia have in common? Do these animal diseases relate mechanistically to fumonisin toxicity in laboratory rats? There is considerable data indicating that disruption of sphingolipid metabolism plays an important early role in all of these diseases. In vitro studies have revealed that fumonisins and structurally related Alternaria alternata f. sp. lycopersici-toxin (AAL-toxin) are potent inhibitors of the enzyme sphinganine (sphingosine) N-acyl transferase (ceramide synthase). Soon after cultured cells or animals are exposed to fumonisins there is a dramatic increase in the free sphingoid base, sphinganine, in tissues, serum and/or urine. Also, free sphingosine concentration increases, complex sphingolipid concentration decreases, and sphingoid base degradation products and other lipid products also increase. It is hypothesized that disruption of sphingolipid metabolism is an early molecular event in the onset and progression of cell injury and the diseases associated with consumption of fumonisins. However, the exact mechanisms responsible for the diseases will not be easily revealed since the role of sphingolipids in cellular regulation is very complex and not yet fully understood. While fumonisin B1 is non-genotoxic it is a complete carcinogen in rat liver. Recent studies indicate that fumonisins inhibit hepatocyte proliferation in rat liver. It has been hypothesized that hepatotoxicity and effects on hepatocyte proliferation are critical determinants for fumonisin B1 cancer initiation and promotion. Alternatively, recent studies have found that fumonisin B1 has mitogenic activity in cultured fibroblasts. It is conceivable that the mitogenic, cytostatic and cytotoxic potential of fumonisin may all contribute to the animal diseases including liver cancer in rats.

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