scholarly journals THE TURNOVER RATE OF PHOSPHOLIPIDS IN THE PLASMA OF THE DOG AS MEASURED WITH RADIOACTIVE PHOSPHORUS

1943 ◽  
Vol 26 (3) ◽  
pp. 333-340 ◽  
Author(s):  
D. B. Zilversmit ◽  
C. Entenman ◽  
M. C. Fishler ◽  
I. L. Chaikoff
Keyword(s):  
Turnover Rate ◽  
Plasma Phospholipid ◽  
Turnover Time ◽  
Radioactive Phosphorus

1. A method for the determination of turnover time and turnover rate of plasma phospholipid is presented. 2. During the postabsorptive state 5.2 to 8.0 mg. of phospholipid phosphorus are turned over per hour in the plasma of dogs weighing 6–9 kilos. 3. The amount of phospholipid in an organ that is supplied by plasma phospholipid per hour is calculated.

scholarly journals ON THE CALCULATION OF "TURNOVER TIME" AND "TURNOVER RATE" FROM EXPERIMENTS INVOLVING THE USE OF LABELING AGENTS

1943 ◽  
Vol 26 (3) ◽  
pp. 325-331 ◽  
Author(s):  
D. B. Zilversmit ◽  
C. Entenman ◽  
M. C. Fishler
Keyword(s):  
Quantitative Determination ◽  
Turnover Rate ◽  
Turnover Time ◽  
New Method ◽  
Animal Body

1. A new method for the determination of an immediate precursor of a substance occurring in the animal body is presented. 2. Calculations on the quantitative determination of the rate of turnover of a substance and their application to experiments involving the use of labeling agents are given. These calculations take into account loss of the isotopic substance by way of breakdown or transport.

DETERMINATION OF THYROTROPHIN BY MEANS OF RADIOACTIVE PHOSPHORUS

1949 ◽  
Vol 3 (4) ◽  
pp. 331-341 ◽  
Author(s):  
ULF BORELL ◽  
HJALMAR HOLMGREN
Keyword(s):  
Radioactive Phosphorus

Determination of circulating red blood cell volume with radioactive phosphorus

1949 ◽  
Vol 7 (2) ◽  
pp. 259
Author(s):  
R.T. Nieset ◽  
Blanche Porter ◽  
W.S. Trautman ◽  
Ralph M. Bell ◽  
William Parson ◽  
...  
Keyword(s):  
Blood Cell ◽  
Cell Volume ◽  
Red Blood Cell ◽  
Radioactive Phosphorus

The determination of the specific activity of plasma glycerol

1982 ◽  
Vol 60 (6) ◽  
pp. 856-858 ◽  
Author(s):  
Clément Gauthier ◽  
Ross Layberry
Keyword(s):  
Column Chromatography ◽  
Turnover Rate ◽  
Specific Activity ◽  
Anionic Exchange ◽  
Removal Of Contaminants ◽  
The One ◽  
Exchange Resins

A method for the determination of the specific activity of plasma glycerol is described. Anionic contaminants are first removed from deproteinized plasma by anionic exchange resins (treated plasma). Glycerol in treated plasma is then quantitatively converted to glycerol-3-phosphate (G3P), which is isolated by column chromatography and counted for 14C radioactivity. The specific activity thus calculated was 100.1 ± 2.9% of a standard of known specific activity. When the specific-activity of glycerol is determined from plasma without prior removal of anionic contaminants (untreated plasma), the calculated specific activity is 1.99 ± 0.15 times higher than the one calculated after their removal. Omission of the removal of contaminants leads to a near 100% error in the calculation of the turnover rate of glycerol.not available

An Automated Method for the Determination of Estrogens in Pregnancy

1968 ◽  
Vol 14 (10) ◽  
pp. 1010-1022 ◽  
Author(s):  
D Ua Conaill ◽  
G G Muir
Keyword(s):  
Turnover Rate ◽  
Good Recovery ◽  
Manual Method ◽  
Color Development ◽  
Automated Method ◽  
Combined Operation ◽  
In Pregnancy

Abstract Ittrich’s method for the determination of total estrogens in urine (1) was adapted for automation on the AutoAnalyzer, using a continuous digester module for the combined operation of phase exchange and color development. The automated method gave good recovery and reproducibility, and correlated well with the manual method. It increased the capacity of this laboratory for estrogen determinations, improved the turnover rate, and reduced the labor involved to a minimum.

Total body phylloquinone and its turnover in human subjects at two levels of vitamin K intake

2002 ◽  
Vol 87 (6) ◽  
pp. 543-553 ◽  
Author(s):  
Robert E. Olson ◽  
Jean Chao ◽  
Donna Graham ◽  
Margaret W. Bates ◽  
Jessica H. Lewis
Keyword(s):  
Vitamin K ◽  
Turnover Rate ◽  
Decay Curve ◽  
Human Subjects ◽  
Control Diet ◽  
Coagulation Factors ◽  
Turnover Time ◽  
Restricted Diet ◽  
Faecal Excretion ◽  
Total Body

The aims of this study were to determine the total body phylloquinone and its metabolic turnover in human subjects using a tracer dose of [5-H3]phylloquinone containing 55·5×104MBq/mmol. Seven subjects aged 22 to 49 years were given 0·3 μg isotopic phylloquinone intravenously on a control diet (75 μg phylloquinone/d) and blood, urine and faeces were sampled periodically for 6 d. Five of these subjects were studied a second time after 3–8 weeks on a low-vitamin K diet (8 μg/d). The changes in the radioactivity of plasma phylloquinone with time were analysed by the method of residuals and fitted to a curve composed of two exponential components. The size of the exchangeable body pool was calculated by isotope dilution. Plasma phylloquinone levels fell during vitamin K restriction but the vitamin K-dependent coagulation factors did not change. After injection the first exponential decay curvet1/2was 1·0 (SD 0·47) H IN THE SUBJECTS ON THE CONTROL DIET AND 0·49 (sd 0·27) h after vitamin K restriction. On the control diet, the second exponentialt1/2was 27·6 (sd 124) h that did not change on the low-vitamin K diet (t1/2=25·1 (sd 13·5) h). These results indicate that the turnover time for phylloquinone in human subjects is about 1·5 d. Urinary excretion of3H-metabolites ranged from 30 % of the administered dose on the control diet to 38 % on the restricted diet and had the same turnover rate as the second component of the plasma decay curves. The exchangeable body pool of phylloquinone declined from about 1·0 μg/kg before restriction to lower values after vitamin K restriction. The faecal excretion of phylloquinone and its metabolites fell from 32 % of the administered dose on the control diet to 13 % on the restricted diet.

Body glucose as fuel for thermogenesis in the white rat exposed to cold

1960 ◽  
Vol 199 (6) ◽  
pp. 1051-1055 ◽  
Author(s):  
Florent Depocas ◽  
Roberto Masironi
Keyword(s):  
Plasma Glucose ◽  
Turnover Rate ◽  
Glycogen Content ◽  
Liver Glycogen ◽  
Turnover Time ◽  
Cold Environments ◽  
Warm Environment ◽  
White Rats ◽  
Liver Glycogen Content ◽  
Carbohydrate Catabolism

Various parameters of glucose metabolism were measured with C14-glucose in unanesthetized warm- and cold-acclimated rats at 30° and 6°C. Exposure of warm-acclimated rats to cold was associated with a decrease in turnover time of plasma glucose, no change in glucose pool size and space, an increase in rates of turnover and oxidation of body glucose, an increase in the ratio of the oxidation rate to the turnover rate, no change in percentage of respiratory CO2 derived from glucose oxidation, and a decrease in liver glycogen content. Approximately reversed changes were observed in cold-acclimated rats transferred from a cold to a warm environment except in the values of turnover time of plasma glucose and terminal liver glycogen content which underwent smaller changes. It is concluded that cold-induced thermogenesis in white rats, whether acclimated to warm or cold environments, is associated with an increase in carbohydrate catabolism proportionate to the increase in energy metabolism.

scholarly journals Determination of steady-state protein breakdown rate in vivo by the disappearance of protein-bound tracer-labeled amino acids: a method applicable in humans

2013 ◽  
Vol 304 (8) ◽  
pp. E895-E907 ◽  
Author(s):  
Lars Holm ◽  
Bruce O'Rourke ◽  
David Ebenstein ◽  
Michael J. Toth ◽  
Rasmus Bechshoeft ◽  
...  
Keyword(s):  
Amino Acids ◽  
Steady State ◽  
Exponential Decay ◽  
Turnover Rate ◽  
Deuterium Oxide ◽  
Protein Breakdown ◽  
Breakdown Rate

A method to determine the rate of protein breakdown in individual proteins was developed and tested in rats and confirmed in humans, using administration of deuterium oxide and incorporation of the deuterium into alanine that was subsequently incorporated into body proteins. Measurement of the fractional breakdown rate of proteins was determined from the rate of disappearance of deuterated alanine from the proteins. The rate of disappearance of deuterated alanine from the proteins was calculated using an exponential decay, giving the fractional breakdown rate (FBR) of the proteins. The applicability of this protein-specific FBR approach is suitable for human in vivo experimentation. The labeling period of deuterium oxide administration is dependent on the turnover rate of the protein of interest.

Improvements in the determination of the turnover rate of plasma thyroxine in avian species: application to the Japanese quail

1987 ◽  
Vol 114 (2) ◽  
pp. 191-198 ◽  
Author(s):  
E. J. Cookson ◽  
J. Glover
Keyword(s):  
Japanese Quail ◽  
Half Life ◽  
Turnover Rate ◽  
Specific Activity ◽  
Simple Procedure ◽  
High Specific Activity ◽  
Future Application ◽  
Sodium Thiocyanate ◽  
Plasma Samples

ABSTRACT The disappearance of the thyroid hormone thyroxine (T4) from plasma in fully grown male Japanese quail can be described as a first order process with a rate constant of 0·178 ± 0·013/h (mean±s.e.m., n = 8), which represents a half-life of 3·90 h. A small amount of [125I]T4 in relation to total circulating T4 was injected i.v. into Japanese quail and plasma samples were taken at appropriate time-intervals for the determination of residual plasma radioactivity. The rate of disappearance of [125I]T4 was subsequently equated to the turnover rate of the endogenous hormone. Previous methods were modified to overcome problems arising from possible disturbance of plasma T4 metabolism, recirculation of radiolabelled iodide, and to purify the [125I]T4 from the plasma samples. By using labelled T4 of very high specific activity, the amount of [125I]T4 administered was kept much smaller than has been used in previous studies on Japanese quail, thus limiting any interference with plasma T4 dynamics. To minimize any disturbance of plasma T4 metabolism, only four blood samples were taken, at three-hourly intervals after the injection of [125I]T4. The rapid turnover of T4 produced a large amount of labelled inorganic iodide, the re-entry of which into the plasma T4 pool was inhibited by s.c. administration of sodium thiocyanate 1 h before injection of[125I]T4. Assay of the true [125I]T4 turnover was significantly improved over that used in previous studies by purifying the [125I]T4 from the plasma samples chromatographically. The samples were applied to small Sephadex G-25 columns with sodium hydroxide (0·1 mol/l) as the eluant. This simple procedure clearly separated the [125I]T4 from the other radioiodinated plasma components such as free iodide, non-hormonal iodinated proteins and triiodothyronine (T3), thus enabling a more accurate assessment of the residual labelled T4 concentration in the plasma and hence the T4 half-life. The future application of this method to the study of plasma T4 turnover under various experimental conditions is discussed and the possible involvement of T4 turnover studies in the assessment of T4 to T3 conversion is considered. J. Endocr. (1987) 114, 191–198

scholarly journals Determination of Bile Acid Pool Size, Turnover Time, and Distribution of Male Broiler Chicks During the First

1987 ◽  
Vol 66 (11) ◽  
pp. 1853-1858 ◽  
Author(s):  
JACK GREEN ◽  
THOMAS KELLOGG ◽  
ROBERT KEIRS ◽  
ROBERT COOPER
Keyword(s):  
Bile Acid ◽  
Turnover Time ◽  
Pool Size ◽  
Broiler Chicks ◽  
Bile Acid Pool ◽  
Acid Pool ◽  
Bile Acid Pool Size
Sign in / Sign up

Export Citation Format

Share Document