Search results for "rats"
showing 10 items of 3537 documents
A time course investigation of vitamin A level and lipid composition of the liver endoplasmic reticulum in rats following treatment with congeneric p…
1990
Abstract The drug metabolizing enzyme activities, the vitamin A content and the fatty acid composition in the endoplasmic reticulum membrane were studied in rat liver after a single injection of the polychlorobiphenyls (PCBs) 3,3′,4,4′-tetrachlorobiphenyl [(3,4)2Cl] or 2,2′,4,4′,5,5′-hexachlorobiphenyl [(2,4,5)2Cl], 300 μ mol/kg each. The microsomal vitamin A level was markedly lowered 3 days after treatment with (3,4)2Cl, a coplanar type inducer of cytochrome P-450. A marked increase in microsomal AHH and UDPGT activities occurred within 3 days after injection of (3,4)2Cl whereas (2,4,5,)2Cl treatment enhanced APDM activity only. Arachidonic, stearic and linoleic acid microsomal contents w…
Crystalloid lysozyme inclusions in Paneth cells of vitamin A-deficient rats.
1990
The effect of vitamin A-deficiency on jejunal Paneth cells in rats was investigated. Crystalloid particles were observed in secretion granules of Paneth cells from 6 out of 8 rats with vitamin A-deficiency. The particles were similar to those found in Paneth cells under other experimental conditions. Using an immuno-electron-microscopic technique we demonstrated a clear lysozyme immunoreactivity of these particles. In 2 vitamin A-deficient rats tubular structures have been detected in addition to the crystalloid particles. Crystalloid particles or tubular structures were not detectable in a control group of 8 vitamin A-supplemented rats. The morphological alterations of Paneth cells may be …
A time-course investigation of vitamin A levels and drug metabolizing enzyme activities in rats following a single treatment with prototypic polychlo…
1987
Xenobiotics previously characterized as selective inducers of drug-metabolizing enzymes were chosen to probe possible relationships between enzyme induction and vitamin A metabolism. Liver, kidney and serum retinol and retinyl palmitate levels were investigated in male Sprague--Dawley rats receiving a single i.p. injection of the polychlorinated biphenyls (PCBs), 2,2',5,5'-tetrachlorobiphenyl, 3,3',4,4'-tetrachlorobiphenyl or 2,2',4,4',5,5'-hexachlorobiphenyl (300 mumol/kg) or 1,1,1-trichloro-2,2-bis-(4-chlorophenyl)-ethane (DDT) (150 mumol/kg). While 2,2',5,5'-tetrachlorobiphenyl, a weak or non-inducer, and 2,2',4,4',5,5'-hexaclorobiphenyl and DDT, phenobarbital-type inducers of cytochrome…
Vitamin A in parenteral nutrition: uptake and distribution of retinyl esters after intravenous application.
1989
Short-term parenteral application of vitamin A was examined in rats. Retinyl margarinate, which is chemically similar to physiological retinyl esters, was used in vitamin A-depleted rats to study uptake, distribution, and storage of retinyl esters in tissues. Vitamin A-depleted and Vitamin A-sufficient rats were infused with a micellar suspension of retinyl margarinate for 7 h and then killed at different times. Retinyl margarinate was directly taken up by all tissues examined. It appears that infusion of retinyl esters in micellar form provides a direct way to supply vitamin A to peripheral, vitamin A-dependent tissues. Therefore, a short-term infusion of retinyl esters with an emulsifier …
Effects of vitamin A deficiency on mitochondrial function in rat liver and heart.
2000
The aim of this study was to investigate comparative effects of vitamin A deficiency on respiratory activity and structural integrity in liver and heart mitochondria. Male rats were fed a liquid control diet (control rats) or a liquid vitamin A-deficient diet (vitamin A-deficient rats) for 50 days. One group of vitamin-A deficient rats was refed a control diet for 15 days (vitamin A-recovered rats). To assess the respiratory function of mitochondria the contents of coenzyme Q (ubiquinone, CoQ), cytochrome c and the activities of the whole electron transport chain and of each of its respiratory complexes were evaluated. Chronic vitamin A deficiency promoted a significant increase in the endo…
Age-dependent differences in the effect of phenprocoumon on the vitamin K1-epoxide cycle in rats
1980
Abstract The anticoagulant activity and the pharmacokinetics of phenprocoumon as well as the effect of phenprocoumon on the vitamin K1-epoxide cycle in younger (12 weeks) and older (36 weeks) male inbred Lewis rats has been examined in a study of the mechanism responsible for the increase in the responsiveness to oral anticoagulant drugs (OAD's) with increasing age. After a single i.v.-dose of phenprocoumon (0†355 mg kg−1 the anticoagulant effect obtained was greater in older than in younger rats. There were no differences between younger and older rats in the rate of elimination, volume of distribution and in the free fraction and free concentration values of phenprocoumon in plasma and li…
Long-Term Administration of High Dose Vitamin A to Rats Does Not Cause Fetal Malformations: Macroscopic, Skeletal and Physicochemical Finds
1996
A rat model was used to investigate whether high oral doses of vitamin A lead to fetal malformations and to what extent retinyl esters (RES) are transferred from the mother to the fetuses. Retinol and RES concentrations in plasma behave similarly in rats and humans. When high concentrations of vitamin A are administered, plasma retinol concentrations remain relatively constant, whereas plasma RES increased in parallel with the dose. To achieve an elevation from approximately 150 to > 1525 nmol x L(-1) in the experimental group before mating, female Ibm: RORO (spf) rats were fed a maintenance diet enriched with 15.2 x 10(3) retinol equivalents (RE) x kg(-1) at the start and increased stepwis…
A Deficiency in Respiratory Complex I in Heart Mitochondria from Vitamin A-Deficient Rats Is Counteracted by an Increase in Coenzyme Q
1997
Defects of NADH:coenzyme Q oxidoreductase (complex I) of mitochondria have been described in many congenital and acquired diseases. Administration of coenzyme Q (CoQ, ubiquinone) has been shown to benefit patients with some of these diseases. However, the mechanisms by which CoQ exerts the therapeutic effects are not clearly understood. A reason could be the lack of saturation of CoQ, in kinetic terms, for complex I activity. However, this hypothesis has not been proved in vivo because of the difficulty to incorporate CoQ into the mitochondrial membranes. We have found a deficiency in respiratory complex I in heart mitochondria from vitamin A-deficient rats which was accompanied by high CoQ…
Vitamin A deficiency causes oxidative damage to liver mitochondria in rats.
2000
Mitochondrial damage in rat liver induced by chronic vitamin A-deficiency was studied using three different groups of rats: (i) control rats, (ii) rats fed a vitamin A-free diet until 50 d after birth and (iii) vitamin A-deficient rats re-fed a control diet for 30 d. No statistical difference in body weight and food intake was found between control and vitamin A-deficient rats. Liver GSH concentration was similar in both groups. However, in vitamin A-deficient rats, the mitochondrial GSH/GSSG ratio was significantly lower and the levels of malondialdehyde (MDA) and 8-oxo-7, 8-dihydro-2'-deoxyguanosine (oxo8dG) were higher when compared to control rats. These values were partially restored i…
N-3 fatty acids modulate antioxidant status in diabetic rats and their macrosomic offspring.
2006
We investigated the role of dietary n-3 polyunsaturated fatty acids (n-3 PUFA) in the modulation of total antioxidant status in streptozotocin (STZ)-induced diabetic rats and their macrosomic offspring. Female wistar rats, fed on control diet or n-3 PUFA diet, were rendered diabetic by administration of five mild doses of STZ on day 5 and were killed on days 12 and 21 of gestation. The macrosomic (MAC) pups were killed at the age of 60 and 90 days. Lipid peroxidation was measured as the concentrations of plasma thiobarbituric acid reactive substances (TBARS), and the total antioxidant status was determined by measuring (i) plasma oxygen radical absorbance capacity (ORAC), (ii) plasma vitami…