Studies of the Metabolism of Asialotransferrins: the in Vivo Behavior of Baboon and Rhesus Asialotransferrins

1975 ◽  
Vol 53 (12) ◽  
pp. 1255-1261 ◽  
Author(s):  
E. Regoeczi ◽  
M. W. C. Hatton ◽  
K.-L. Wong
Keyword(s):  
Hepatic Uptake ◽  
Average Increase ◽  
Tracer Technique ◽  
Short Term ◽  
Dual Isotope ◽  
Isotope Tracer ◽  
Catabolic Rate ◽  
Nonprimate Mammal ◽  
Reduced Data

The catabolism and distribution of rhesus and baboon asialotransferrins relative to the corresponding parent proteins were studied in rabbits using a dual isotope tracer technique. Also a similar study with the baboon proteins in a baboon is reported.The metabolic data obtained in rabbits with both rhesus and baboon transferrins was close to the values established in a previous study for rabbit transferrin. Desialylation resulted in an average increase in the fractional catabolic rate of rhesus transferrin by 22.7%. This change is similar to that found earlier with asialotransferrins from several nonprimate mammals which are thought not to interact with the hepatic asialoglycoprotein receptor.Two kinetically distinct fractions were identified in baboon asialotransferrin. One of these, amounting to approximately one-third of the protein, was eliminated from the circulation very rapidly. The remaining two-thirds constituted a slowly catabolized fraction which behaved in vivo similarly to rhesus asialotransferrin. Unlike the rapidly cleared fraction, elimination of the slowly catabolized fraction in baboon asialotransferrin is probably not mediated by the hepatic asialoglycoprotein receptor. An amount comparable to the rapidly eliminated fraction in baboon asialotransferrin was recovered with the liver of rats in short-term experiments. In rats which were preinjected with chicken acid α1-glycoprotein the hepatic uptake of baboon asialotransferrin was markedly reduced. Data obtained in the baboon agreed with the findings in rabbits, although transferrin turnover was slower in the baboon.From its behavior in vivo as an asialoglycoprotein, baboon transferrin shows greater resemblance to human transferrin than rhesus transferrin. This conclusion is supported by carbohydrate analyses which show an intermediate position for baboon transferrin between man and a nonprimate mammal (rabbit), and a similarity between rhesus and rabbit transferrins.

Studies of the Metabolism of Asialotransferrins: Potentiation of the Catabolism of Human Asialotransferrin in the Rabbit

1974 ◽  
Vol 52 (3) ◽  
pp. 155-161 ◽  
Author(s):  
E. Regoeczi ◽  
M. W. C. Hatton ◽  
K.-L. Wong
Keyword(s):  
Tracer Technique ◽  
Transfer Rates ◽  
Dual Isotope ◽  
Human Transferrin ◽  
Isotope Tracer ◽  
Human Control ◽  
Homologous Protein ◽  
Catabolic Rate ◽  
The Difference ◽  
Control Protein

The catabolism and distribution of simultaneously injected rabbit transferrin and rabbit asialotransferrin was studied in five rabbits using a dual-isotope tracer technique. Similar studies were performed with human transferrin and human asialotransferrin in two humans, seven rabbits, and a rat.In all experiments, the catabolic rate of the asialotransferrin was higher than the corresponding value for the control protein. The difference averaged at 15% for rabbits and 29% for humans when homologous protein preparations were used. There were no concomitant differences in capillary transfer rates or in the partition of the labeled proteins between intra- and extravascular spaces.The catabolic rate of human transferrin in rabbits was not significantly different from that of the corresponding homologous protein. In contrast, human transferrin from which 92–100% of the sialyl residues had been removed was catabolized in rabbits at approximately 3.5 times the rate for homologous asialotransferrin. Substantial difference was found between the elimination of human control and asialotransferrins in the rat as well.

scholarly journals True ileal digestibility of legumes determined by dual-isotope tracer method in Indian adults

2019 ◽  
Vol 110 (4) ◽  
pp. 873-882 ◽  
Author(s):  
Sindhu Kashyap ◽  
Aneesia Varkey ◽  
Nirupama Shivakumar ◽  
Sarita Devi ◽  
Rajashekar Reddy B H ◽  
...  
Keyword(s):  
Mung Bean ◽  
Deuterium Oxide ◽  
Protein Digestibility ◽  
Plant Protein ◽  
Tracer Technique ◽  
Feeding Method ◽  
Dual Isotope ◽  
Ileal Digestibility ◽  
Isotope Tracer ◽  
Plant Protein Sources

ABSTRACTBackgroundGood-quality plant protein sources are important for protein adequacy in a balanced diet. Legumes are known to be a source of good quality plant protein, but the true ileal digestibility of indispensable amino acids (IAAs) of commonly consumed legumes is not known in humans.ObjectivesIn this study we measured the true ileal IAA digestibility of 2H-intrinsically labeled chickpea, yellow pea, and mung bean (hulled and dehulled) protein, using the dual-isotope tracer technique referenced to a standard protein ([U-13C] spirulina). The study also aimed to validate the use of [U-13C] spirulina as a reference protein in this method.Methods2H-intrinsically labeled legumes, obtained by watering plants with deuterium oxide (2H2O), were administered in a plateau feeding method to healthy Indian adults to measure their true ileal IAA digestibility with the dual-isotope tracer technique, using [U-13C] spirulina protein or a 13C-algal IAA mixture as the standard.ResultThe true ileal IAA digestibilities (mean ± SD) of chickpea, yellow pea, and mung bean were 74.6 ± 0.8%, 71.6 ± 1.3%, and 63.2 ± 1.5%, respectively. The true mean ileal IAA digestibility of mung bean when referenced to [U-13C] spirulina protein or a 13C-algal IAA mixture did not differ significantly (63.2 ± 1.5% versus 64.0 ± 2.4%, P > 0.05). The true ileal IAA digestibility of mung bean improved to 70.9 ± 2.1% after dehulling.ConclusionsThe true mean ileal IAA digestibility of legumes in healthy Indian adults was lower than expected. Traditional processing techniques such as dehulling improve protein digestibility by about 8%. This study was registered in the Clinical Trials Registry of India (CTRI): CTRI/2017/11/010468 (http://ctri.nic.in, accessed on 28/03/2019).

Studies of the Metabolism of Asialotransferrins: Relationship Between the Carbohydrate Composition of Bovine, Canine, and Porcine Asialotransferrins and their Metabolic Behavior in the Rabbit

1974 ◽  
Vol 52 (10) ◽  
pp. 845-853 ◽  
Author(s):  
M. W. C. Hatton ◽  
E. Regoeczi ◽  
K.-L. Wong
Keyword(s):  
Negative Charge ◽  
Transfer Rates ◽  
Dual Isotope ◽  
Isotope Tracer ◽  
Native Proteins ◽  
Terminal Galactose ◽  
The Difference ◽  
Metabolic Behavior ◽  
Galactosyl Residues

The catabolism and distribution of bovine, canine, and porcine asialotransferrins relative to the corresponding parent proteins were studied in rabbits using a dual-isotope tracer technique. The capillary transfer rates and the partitions between intra- and extravascular spaces of these asialotransferrins did not differ significantly from the corresponding values for the control proteins but the asialotransferrins were catabolized faster. However, the difference in catabolic rates only amounted to 13–20%, which was in the same order as established previously for rabbit asialotransferrin (15%) but was considerably less than for human asialotransferrin (350%). This behavior clearly indicates that, in contradistinction to human asialotransferrin, bovine, canine, and porcine asialotransferrins are not eliminated from the plasma of rabbits via the Ashwell–Morell pathway for asialoglycoproteins.To explain the discrepancy in the behavior in vivo of the heterologous asialotransferrins, the carbohydrate compositions of the native proteins were measured and compared. The data show that bovine, porcine, dog, and rabbit transferrins contain approximately half the amount of carbohydrate found for the human protein. Furthermore, the human asialotransferrin carbohydrate chains terminate with galactosyl residues, which can be cleaved by β-galactosidase, whereas bovine, porcine, dog, and rabbit asialotransferrins do not liberate galactose in the presence of β-galactosidase.These observations are consistent with the hypothesis that the rapid elimination of a heterologous asialotransferrin can only be expected if the terminal galactose residues are accessible and that the slightly accelerated catabolism of homologous and certain heterologous asialotransferrins is due to loss of negative charge from the protein.

Effects of short-term saffron (Crocus sativus L.) intake on the in vivo activities of xenobiotic metabolizing enzymes in healthy volunteers

2019 ◽  
Vol 130 ◽  
pp. 32-43 ◽  
Author(s):  
Elias Begas ◽  
Maria Bounitsi ◽  
Thomas Kilindris ◽  
Evangelos Kouvaras ◽  
Konstantinos Makaritsis ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Crocus Sativus ◽  
Short Term ◽  
Metabolizing Enzymes ◽  
Xenobiotic Metabolizing Enzymes ◽  
Crocus Sativus L

Case study in 21 st century ecotoxicology: using in vitro aromatase inhibition data to predict short term in vivo responses in adult female fish

2020 ◽  
Author(s):  
Daniel L. Villeneuve ◽  
Brett R. Blackwell ◽  
Jenna E. Cavallin ◽  
Wan‐Yun Cheng ◽  
David J. Feifarek ◽  
...  
Keyword(s):  
Adult Female ◽  
Female Fish ◽  
Aromatase Inhibition ◽  
Short Term ◽  
Inhibition Data

Short‐Term Repeatability of in Vivo Cardiac Intravoxel Incoherent Motion Tensor Imaging in Healthy Human Volunteers

2021 ◽  
Author(s):  
Xiu‐Shi Zhang ◽  
En‐Hui Liu ◽  
Xin‐Yu Wang ◽  
Xin‐Xiang Zhou ◽  
Hong‐Xia Zhang ◽  
...  
Keyword(s):  
Intravoxel Incoherent Motion ◽  
Short Term ◽  
Healthy Human ◽  
Human Volunteers

scholarly journals Glycogen synthesis in the perfused liver of adrenalectomized rats

1976 ◽  
Vol 156 (3) ◽  
pp. 585-592 ◽  
Author(s):  
P D Whitton ◽  
D A Hems
Keyword(s):  
Intact Animal ◽  
Glycogen Synthesis ◽  
Hepatic Metabolism ◽  
Hepatic Glycogen ◽  
Perfused Liver ◽  
Short Term ◽  
Glycogen Accumulation ◽  
Glycogen Deposition ◽  
Adrenalectomized Rats

1. A total loss of capacity for net glycogen synthesis was observed in experiments with the perfused liver of starved adrenalectomized rats. 2. This lesion was corrected by insulin or cortisol in vivo (over 2-5h), but not by any agent tested in perfusion. 3. The activity of glycogen synthetase a, and its increase during perfusion, in the presence of glucose plus glucogenic substrates, were proportional to the rate of net glycogen accumulation. 4. This complete inherent loss of capacity for glycogen synthesis after adrenalectomy is greater than any defect in hepatic metabolism yet reported in this situation, and is not explicable by a decrease in the rate of gluconegenesis (which supports glycogen synthesis in the liver of starved rats). The short-term (2-5h) stimulatory effect of glucocorticoids in the intact animal, on hepatic glycogen deposition, may be mediated partly through insulin action, although neither insulin or cortisol appear to act directly on the liver to stimulate glycogen synthesis.

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