scholarly journals In vivo effect of aflatoxin B1 , on protein synthesis in rat liver

FEBS Letters ◽  
1973 ◽  
Vol 29 (3) ◽  
pp. 329-332 ◽  
Author(s):  
A. Sarasin ◽  
Y. Moulé ◽  
N. Darracq
1968 ◽  
Vol 109 (1) ◽  
pp. 87-91 ◽  
Author(s):  
S. Villa-Treviño ◽  
D. D. Leaver

1. Aflatoxin and the pyrrolizidine alkaloid retrorsine inhibited the incorporation of labelled amino acids into rat liver and plasma proteins in vivo. Inhibition was greater and detected earlier with retrorsine (1hr.) than with aflatoxin (3hr.). 2. Both toxins affected the liver ribosomal aggregates, causing increases in the proportion of monomers plus dimers. The effect of retrorsine was greater than that of aflatoxin. 3. Incorporation of labelled amino acids into proteins of cell-free preparations of liver from rats treated with aflatoxin was lower than in control preparations. The main site of inhibition appeared to be the ribosomes. 4. Both toxins inhibited the incorporation of orotate into liver nuclear RNA 1hr. after administration.


1970 ◽  
Vol 16 (10) ◽  
pp. 959-963 ◽  
Author(s):  
R. W. Detroy ◽  
C. W. Hesseltine

The effect of two inhibitors on the formation of aflatoxin B1 synthetase activity in strain NRRL 2999 Aspergillus parasiticus has been studied. Aflatoxin B1 synthesizing activity was measured in vivo by incorporation of the 14C-methionine methyl group into aflatoxin B1. Cycloheximide at a concentration of 150 μg/ml blocks protein synthesis completely. If addition of cycloheximide is made before B1 synthetase appears, no activity accumulates; if added during accumulation, activity is frozen at the level reached at the time of addition. The cycloheximide effect is reversible since morphogenesis, total protein synthesis, and aflatoxin B1 synthetase activity all resume after removal of the inhibitor.DL-p-Fluorophenylalanine partially inhibits aflatoxin B1 synthesis in vivo; however, its effect upon macromolecular synthesis is incomplete even at high concentration levels. Once formed, the aflatoxin synthetase appears to maintain B1 synthesis when further protein synthesis is blocked; i.e., it is not rapidly degraded.


1978 ◽  
Vol 75 (4) ◽  
pp. 1745-1749 ◽  
Author(s):  
R. G. Croy ◽  
J. M. Essigmann ◽  
V. N. Reinhold ◽  
G. N. Wogan
Keyword(s):  

1974 ◽  
Vol 140 (3) ◽  
pp. 549-556 ◽  
Author(s):  
R. L. Boeckx ◽  
K. Dakshinamurti

The effect of administration of biotin to biotin-deficient rats on protein biosynthesis was studied. Biotin treatment resulted in stimulation by more than twofold of amino acid incorporation into protein, both in vivo and in vitro in rat liver, pancreas, intestinal mucosa and skin. Analysis of the products of amino acid incorporation into liver proteins in vivo and in vitro indicated that the synthesis of some proteins was stimulated more than twofold, but others were not stimulated at all. This indicates a specificity in the stimulation of protein synthesis mediated by biotin.


1980 ◽  
Vol 186 (1) ◽  
pp. 35-45 ◽  
Author(s):  
A J Dickson ◽  
C I Pogson

Methods have been derived which permit the isolation of undergraded polyribosomes from isolated rat liver cells. Under the conditions used the polyribosome profile of hepatocytes immediately after isolation was essentially identical with that from intact liver. However, during incubation of cells in complex physiological media there was a progressive dissociation of polyribosomes. The addition of a variety of factors that produce reaggregation of polyribosomes in rat liver in vivo did not prevent dissociation during cell incubations. Although large polyribosomes were lost most rapidly, the albumin-synthesizing capacity of isolated cells was not selectively lost when compared with total protein synthesis. The significance of these results for the use of isolated hepatocytes in the study of liver protein synthesis is discussed.


1992 ◽  
Vol 13 (5) ◽  
pp. 831-835 ◽  
Author(s):  
Gary S. Jennings ◽  
Franz Oesch ◽  
Pablo Steinberg

1979 ◽  
Vol 178 (3) ◽  
pp. 725-731 ◽  
Author(s):  
R D Conde

The effect of hypophysectomy on the protein metabolism of the liver in vivo was studied. Fractional rates of protein synthesis and degradation were determined in the livers of normal and hypophysectomized rats. Synthesis was measured after the injection of massive amounts of radioactive leucine. Degradation was estimated either as the balance between synthesis and accumulation of stable liver proteins or from the disappearance of radioactivity from the proteins previously labelled by the injection of NaH14CO3. The results indicate that: (1) hypophysectomy diminishes the capacity of the liver to synthesize proteins in vivo, mainly of those that are exported as plasma proteins; (2) livers of both normal and hypophysectomized rats show identical protein-degradation rates, whereas plasma proteins are degraded slowly after hypophysectomy.


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