Biosynthesis of pyrimidine nucleotides and level of cytochrome P-450 in rat liver and kidney after clofibrate administration (an in vivo study)

1988 ◽  
Vol 114 (1) ◽  
pp. 59-63 ◽  
Author(s):  
J. Seifert ◽  
Z. Machkov�
Keyword(s):  
Rat Liver ◽  
In Vivo Study ◽  
Pyrimidine Nucleotides ◽  
Liver And Kidney ◽  
Cytochrome P 450

scholarly journals Phenylhydrazine-mediated induction of haem oxygenase activity in rat liver and kidney and development of hyperbilirubinaemia. Inhibition by zinc-protoporphyrin

1984 ◽  
Vol 217 (2) ◽  
pp. 409-417 ◽  
Author(s):  
M D Maines ◽  
J C Veltman
Keyword(s):  
Rat Liver ◽  
Zinc Protoporphyrin ◽  
Serum Total Bilirubin ◽  
Potent Inducer ◽  
Oxygenase Activity ◽  
Liver And Kidney ◽  
Haem Oxygenase ◽  
Cytochrome P 450

Phenylhydrazine was found to be a potent inducer of microsomal haem oxygenase activity in rat liver and kidney, but not in spleen. The phenylhydrazine-mediated increase in haem oxygenase activity was time-dependent. Maximum activity was attained 12h after treatment in the liver, and 24h after treatment in the kidney. The increases in the activity of haem oxygenase in the liver and the kidney could be inhibited by cycloheximide. Furthermore, the increases could not be elicited by the treatment of microsomal preparations in vitro with phenylhydrazine. In consonance with the increased haem oxygenase activity, a marked increase (16-fold) was observed in the serum total bilirubin concentration in phenylhydrazine-treated rats. The mechanism of haem degradation promoted by phenylhydrazine in vivo appears to differ from that in vitro; only in the former case is bilirubin formed as the end-product of haem degradation. When rats were given zinc-protoporphyrin (40 mumol/kg) 12h before and after phenylhydrazine treatment, the phenylhydrazine-mediated increases in haem oxygenase activity in the liver and the kidney were effectively blocked. Treatment of rats in vivo with the metalloporphyrin also inhibited the activity of splenic haem oxygenase, and promoted a major decrease in the serum bilirubin levels. In phenylhydrazine-treated animals, the microsomal content of cytochrome P-450 was significantly decreased in the absence of a decrease in the microsomal haem concentration. The decrease in cytochrome P-450 content was accompanied by an increased absorption in the 420nm region of the reduced CO-difference spectrum, suggesting the conversion of the cytochrome to an inactive form. The marked depletion of cellular glutathione levels suggests that this conversion may be related to the action of active intermediates and free radicals formed in the course of the interaction of phenylhydrazine with the haem moiety of cytochrome P-450.

Mechanisms of conversion of xanthine dehydrogenase to xanthine oxidase in ischemic rat liver and kidney

1988 ◽  
Vol 254 (5) ◽  
pp. G753-G760 ◽  
Author(s):  
T. G. McKelvey ◽  
M. E. Hollwarth ◽  
D. N. Granger ◽  
T. D. Engerson ◽  
U. Landler ◽  
...  
Keyword(s):  
Xanthine Oxidase ◽  
Rat Liver ◽  
Ischemia Reperfusion ◽  
Xanthine Dehydrogenase ◽  
Serum Glutamic Oxaloacetic Transaminase ◽  
Liver Model ◽  
Damage Process ◽  
Liver And Kidney ◽  
Sulfhydryl Modification

Previous studies have proposed and supported a role for the proteolytic, irreversible conversion of xanthine dehydrogenase to xanthine oxidase (XO) in postischemic injury in a wide variety of organs. A second mechanism of conversion, due to sulfhydryl modification and reversible with dithiothreitol (DTT), is potentially important but has not been well investigated. In this study rat liver and kidney were found to produce significant amounts of DTT-reversible XO during normothermic global ischemia. Formation of reversible XO precedes that of irreversible XO by approximately 0.5 h with a strong correlation (r = 0.92) existing between the rate of irreversible XO formation and the concentration of reversible XO. The formation of reversible XO is preceded by a depletion of glutathione with concentrations of glutathione during ischemia correlating (r = 0.85) with the observed concentration of reversible XO. While a large increase in the extent of liver damage occurs concurrently with conversion in an in vivo liver model of liver ischemia, an ischemia-reperfusion regimen (1 h of ischemia plus 0.5 h of reperfusion) that resulted in no conversion caused significant elevations in serum glutamic pyruvic transaminase and serum glutamic-oxaloacetic transaminase. Rats depleted of XO by tungsten dieting release 65% less enzyme after the same insult, suggesting that endogenous XO may also participate in the damage process independent of any conversion.

The influence of age and barbital treatment on the content of cytochrome P-450 and b5 and on the activity of glucose-6-phosphatase in microsomes of the rat liver and kidney

1973 ◽  
Vol 22 (8) ◽  
pp. 905-910 ◽  
Author(s):  
Dieter Müller ◽  
Dieter Förster ◽  
Holger Dietze ◽  
Ralf Langenberg ◽  
Wolfgang Klinger
Keyword(s):  
Rat Liver ◽  
Liver And Kidney ◽  
Cytochrome P 450

scholarly journals Precocious development of glucuronidating and hydroxylating enzymes in chick embryos treated with pituitary grafts

1975 ◽  
Vol 152 (2) ◽  
pp. 325-331 ◽  
Author(s):  
Graham J. Wishart ◽  
Geoffrey J. Dutton
Keyword(s):  
Chorioallantoic Membrane ◽  
Pars Distalis ◽  
Liver And Kidney ◽  
Embryo Liver ◽  
First Time ◽  
Cytochrome P 450 ◽  
Isolated Liver ◽  
Precocious Development ◽  
Nadph Cytochrome C Reductase

1. Initiation of precocious development of UDP-glucuronyltransferase by an endogenous factor is reported for the first time. 2. This development occurs in chick embryo liver and kidney after grafting of the cephalic lobe of chicken pars-distalis pituitary tissue on to the chorioallantoic membrane, and in liver results in a rise in the enzyme activity from virtually zero to ‘adult’ values. Aniline hydroxylase also precociously develops in the liver of grafted embryos, its activity rising from one-third to the full adult value. Specific activities of glucose 6-phosphatase, cytochrome P-450 and NADPH–cytochrome c reductase did not significantly change. 3. The response of the transferase does not require the presence of host pituitary gland nor, apart from 1 day's necessary initiation, the presence of the graft itself. 4. The host becomes competent to respond on the 14th day of incubation; response continues for at least 3 days after removal of the graft, and for 2 days in the isolated liver. Grafting of embryonic pars distalis younger than 17 days does not evoke a response in the host liver. 5. Secretion of the pituitary factor increases suddenly some 24–48h before the naturally developing surge in liver UDP-glucuronyltransferase activity and may be responsible for initiating this rise in vivo. 6. The factor is probably not a growth or luteinizing hormone; its nature and the likelihood of a secondary hormone acting directly on the liver are discussed.

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