摘要:

The concentration of individual plasma apoproteins together with the in vivo metabolism of 125I-labelled high density lipoprotein was studied in an adult male patient with abetalipoproteinemia. Plasma concentrations of cholesterol (26 mg/dl) and triglyceride (5 mg/dl) were markedly reduced and apoprotein B was absent. The concentrations of apo AI, apo All, CI, CII, Oiland E were also lower than in normal subjects. To further evaluate these changes we studied the in vivo metabolism of autologous 125I-labelled HDL over a period of 13 days. The plasma half-life (4.1 days) and fractional catabolic rate (0.23) were similar to previously reported values for normal subjects, but overall synthesis of apoproteins AI (5.7 mg/kg/day) and All (3.6 mg/kg/day) were significantly reduced. After separation of delipidated HDL apoproteins by polyacrylamide-gel electrophoresis we were unable to demonstrate any differences in the half-life or fractional catabolic rates of apoproteins AI and All and CII plus OIL We conclude that the low concentrations of apoproteins AI and All in the plasma of our patient with abetalipoproteinemia are a consequence of reduced synthesis and do not reflect enhanced catabolism.

ISSN:0250-6807    

DOI:10.1159/000176473

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

Hormonal and metabolic regulation of endogenous triglyceride hydrolysis was studied in triglyceride-enriched hearts obtained from rats fed 3 days with a trierucate-rich diet. Endogenous lipolysis was determined by measuring glycerol release during in vitro perfusion of the hearts. It appeared that there was a direct relation between the contractile state of the heart, the rate of glycerol release in the coronary effluent and the Ca2+ concentration in the perfusion medium. During Ca2+-free perfusion, 2,4-dinitrophenol stimulated oleate oxidation and this, as well as the addition of 2 • 10–7M glucagon, induced a marked stimulation of lipolysis. Insulin did not affect glucagon- and norepinephrine-stimulated lipolysis during substrate-free perfusion. The presented experiments point out that in lipid-enriched rat hearts the activity of the tissue lipase may be controlled by the rate of β-oxidation and re-esterification of the liberated fatty acids, as well as by a shift to utilization of carbohydrate instead of fatty acids for energy su

ISSN:0250-6807    

DOI:10.1159/000176474

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

Decreased riboflavin concentrations were again found in different tissues from old rats (23 months of age) as compared to younger animals (11 months of age). This decrease was observed in the liver, heart and brain (-7 to -10%) and mainly in the kidneys (-60%). In the first three organs it is due to a decrease in flavin adenine dinucléotide (FAD), whereas most of the time the flavin mononucleotide and free riboflavin (FMN + FR) contents remained unchanged. In the kidneys, both FAD and FMN + FR are decreased, the latter more so than the former. This phenomenon could be explained by a modification in the enzymatic activities involved in the riboflavin FMN-FAD metabolic pathways and would result from a decrease of thyroid activity during aging. In the spleen, the total riboflavin concentration is increased in old rats without changes in the relative ratios of FAD and FMN + FR. No particular effect was observed in lung and muscle tissue during aging

ISSN:0250-6807    

DOI:10.1159/000176475

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

Glutathione peroxidase (EC 1.11.1.9, GSHPx) activity was measured in whole liver, in hepatic cytosol and in whole mitochondria from normal rats and from rats subjected to experimentally induced vitamin E and/or essential fatty acid (EFA) deficiency. The animals were fed and raised on the specific diets for 6 months. The GSHPx activity was significantly decreased in all samples of EFA-deficient rats. This group exhibited a significant increased 20:3ω9/20:4ω6 ratio of the fatty acids (assayed on liver mitochondria). Low specific mitochondrial glutathione peroxidase activity was connected to high 20:3ω9 content and to low 20:4ω6 content. In rats fed a vitamin E-deficient diet, the GSHPx activity was significantly decreased in hepatic cytosol. When the data of all experimental groups were pooled the specific GSHPx activities of the hepatic cytosol correlated significantly to that of whole mitochondria. The specific GSHPx activity of the whole liver, the mitochondrial and the cytosol fractions were found higher in female than in male rats in controls as well as in deficient animals. This difference was affected by the EFA deficiency. In EFA-deficient mitochondria the sex difference in enzymic activity was decreased (half of normal difference). In EFA-deficient cytosol the difference was increased (double of normal difference). However, the total hepatic GSHPx activities were not significantly higher in female than in male rats in any of the groups studied. Thus, EFA deficiency is added to the list of factors influencing the GSHPx activity. It is concluded that it is not possible to use GSHPx activity as a marker for the selenium status in domestic animals such as suggested previously. Thus, selenium is only one of the factors governing the GSHPx le

ISSN:0250-6807    

DOI:10.1159/000176476

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

The purpose of this study was to investigate the metabolic adaptations of the fetus during maternal starvation and to determine the changes of plasma insulin and glucagon concentrations in the fed state and during severe maternal fasting in the chronic fetal sheep preparation. Maternal fasting resulted in a decrease in maternal and fetal plasma glucose as well as a decrease in fetal plasma fructose. Fetal-maternal arterial urea concentration differences increased with maternal fasting, suggesting increased fetal amino acid catabolism. Both maternal and fetal plasma insulin decreased parallel to the decrease in plasma glucose concentration. Maternal glucagon did not change significantly during fasting and with a short-term fast there was no change in fetal glucagon concentration. However, by 6 days of fasting, the fetal glucagon concentration tended to increase.

ISSN:0250-6807    

DOI:10.1159/000176477

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

The quality of different protein sources having a wide spectrum of potential biological values has been assessed with multi-point and single-point assays on growing Sprague-Dawley rats weighing 60 g. Values obtained with multi-point assays, expressed both as absolute and relative values, were well correlated irrespective of the response parameter, i.e. body weight change, body water or body nitrogen (r = 0.980). Single-point assay values based on body nitrogen content were also well correlated with the multi-point assays, but some discrepancies were noted for what assays based on body weight change was concerned. The modification of body protein concentration, in particular of rats fed the protein-free diet, was the main cause of these discrepancies. The problem of reference protein, when protein quality was expressed as relative value, was also discussed.

ISSN:0250-6807    

DOI:10.1159/000176478

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

Serum calcium, inorganic phosphorus and alkaline phosphatase (SAP) have been determined in 75 lactating women and 25 controls. 25 lactating women were re-investigated after administration of calcium and vitamin D supplements for 1 month. Lactating women showed statistically significant hypocalcaemia and raised SAP. However, the elevation of the enzyme level was significantly lower in women with milk intakes of more than ½ litre per day and in those in later months of lactation. The effects of calcium and vitamin D supplementation supported a diagnosis of osteomalacia in a large percentage of lactating women

ISSN:0250-6807    

DOI:10.1159/000176479

出版商:S. Karger AG    

年代:1981

数据来源: Karger