Cholesterol turnover in miniature swine with a portacaval shunt

1979 ◽  
Vol 57 (12) ◽  
pp. 1381-1387 ◽  
Author(s):  
Yung-Sheng Huang ◽  
Suzanne Lussier-Cacan ◽  
Maurice Bidallier ◽  
Liang-Huei Tsay ◽  
Marcel J. Rheault ◽  
...  
Keyword(s):  
Intravenous Injection ◽  
Digital Computer ◽  
Plasma Cholesterol ◽  
Specific Radioactivity ◽  
Portacaval Shunt ◽  
Hypocholesterolemic Effect ◽  
Miniature Swine ◽  
Pool Model

Plasma cholesterol turnover was studied in sham-operated and portacaval-shunted miniature swine following an intravenous injection of labeled cholesterol. The specific radioactivity – time curves for periods of 6–7 weeks and 11–13 weeks were analyzed in both groups by a digital computer according to a two-pool and a three-pool model. In this study, the three-pool model generally provided a better fit to the observed data than did the two-pool model. The half-lives of the first and second exponents were significantly decreased in the shunted animals, indicating an elevated turnover of cholesterol. It is suggested that increased hepatic degradation of cholesterol was responsible for the hypocholesterolemic effect of the shunt in our study.

The Distribution of [14C]Cholesterol in Muscle and Skin of Rhesus Monkeys after Intravenous Injection

1976 ◽  
Vol 50 (4) ◽  
pp. 307-310
Author(s):  
C. D. Moutafis ◽  
N. B. Myant
Keyword(s):  
Intravenous Injection ◽  
Rhesus Monkeys ◽  
Plasma Cholesterol ◽  
Specific Radioactivity ◽  
Compartment System ◽  
Local Synthesis ◽  
Single Intravenous Injection ◽  
Small Pool ◽  
Slow Turnover

1. The specific radioactivity of [14C]cholesterol in plasma and in serial biopsies of muscle and skin was measured in Rhesus monkeys for 156 days after a single intravenous injection of [14C]cholesterol. 2. Analysis of the specific radioactivity—time curves in terms of a two-compartment system indicated that all the cholesterol of muscle is exchangeable with the plasma cholesterol and that local synthesis does not contribute significantly to the cholesterol in muscle. 3. Analysis of the curve for specific radioactivity of skin cholesterol suggested the presence of a small pool of cholesterol with slow turnover. A contribution to skin cholesterol from local synthesis could not be excluded.

The Lipids and Lipoproteins of Human Peripheral Lymph, with Observations on the Transport of Cholesterol from Plasma and Tissues into Lymph

1973 ◽  
Vol 45 (3) ◽  
pp. 313-329 ◽  
Author(s):  
D. Reichl ◽  
L. A. Simons ◽  
N. B. Myant ◽  
J. J. Pflug ◽  
G. L. Mills
Keyword(s):  
Total Cholesterol ◽  
Intravenous Injection ◽  
Plasma Cholesterol ◽  
Human Subjects ◽  
Specific Radioactivity ◽  
Cholesterol Concentration ◽  
Apo B ◽  
Peripheral Lymph ◽  
Lipids And Lipoproteins ◽  
Slow Turnover

1. The lipids and lipoproteins of lymph obtained from the dorsum of the foot were examined in seven human subjects. 2. The concentration of total cholesterol in lymph was about one-tenth that in plasma and was significantly correlated with the plasma total cholesterol concentration. The ratio of esterified to total cholesterol in lymph was similar to that in plasma. 3. Triglyceride was detectable in lymph, but the concentration was less than one-tenth that in plasma and was unrelated to the plasma triglyceride concentration. 4. No lipase activity was detectable in lymph, either before or after intravenous injection of heparin. 5. Cholesterol-esterifying activity was detected in four samples of lymph. 6. The major lipoprotein antigens of human plasma (apo-A, apo-B and apo-C) were present in whole lymph, but their distribution in fractions of different density was different from that in plasma. 7. [14C]Cholesterol, injected intravenously, appeared in lymph within 30 min of the injection, indicating that some of the cholesterol in lymph is derived directly from plasma. 8. At intervals greater than 29 days after a single intravenous injection of [14C]-cholesterol, the specific radioactivity of lymph cholesterol was greater than that of plasma cholesterol, indicating that some of the cholesterol in lymph is derived from tissue pools of cholesterol with slow turnover.

scholarly journals Compartmentation between glycolysis and gluconeogenesis in rat liver

1968 ◽  
Vol 110 (2) ◽  
pp. 303-312 ◽  
Author(s):  
C. J. Threlfall ◽  
D. F. Heath
Keyword(s):  
Kinetic Analysis ◽  
Intravenous Injection ◽  
Rat Liver ◽  
Isotopic Exchange ◽  
Direct Evidence ◽  
Specific Radioactivity ◽  
Glycolytic Pathway ◽  
Glucose Phosphorylation

1. The specific radioactivity–time relationships of glucose, glucose 6-phosphate, glycerol 1-phosphate and UDP-glucose were determined in rat liver after the intravenous injection of [U−14C]fructose, and a kinetic analysis was carried out. The glucose 6-phosphate pool was found to be compartmented into gluconeogenic and glycolytic components, and evidence was obtained that the triose phosphates were similarly compartmented. The glycolytic pathway was fed by glycogenolysis and glucose phosphorylation. There was no direct evidence that glycogenolysis fed only the glycolytic pathway, but this interpretation would make the liver resemble other organs in this respect. 2. UDP-glucose was not formed solely from gluconeogenic glucose 6-phosphate, as there was some dilution of label in the intervening glucose 1-phosphate pool, probably from glycogenolysis, though other pathways cannot be excluded. 3. The data cannot be explained by isotopic exchange.

Hypercholesterolemia of total starvation: its mechanism via tissue mobilization of cholesterol

1975 ◽  
Vol 229 (2) ◽  
pp. 365-369 ◽  
Author(s):  
JC Swaner ◽  
WE Connor
Keyword(s):  
Adipose Tissue ◽  
Cholesterol Metabolism ◽  
Plasma Cholesterol ◽  
Specific Radioactivity ◽  
Cholesterol Content ◽  
Cholesterol Concentration ◽  
Tissue Cell ◽  
Adipose Tissue Cell ◽  
Total Starvation ◽  
Linear Decay

After the establishment of a relatively linear decay curve for plasma [4-14C]cholesterol, rabbits were starved for 26-32 days. The plasma cholesterol concentration increased 400% during starvation. Concurrently, the plasma triglyceride level declined by 50%. While the plasma cholesterol was rising, the cholesterol specific radioactivity of the plasma remained unchanged in starved animals, but in control animals the plasma cholesterol specific radioactivity declined substantially. The cholesterol content of the liver and adipose tissue increased with starvation. The cholesterol specific radioactivities relative to plasma for adipose tissue were lower in the starved animals versus controls. These results support the hypothesis that cholesterol stored in the lipid droplet of the adipose tissue cell is released into plasma and is the chief source of the hypercholesterolemia observed during complete caloric starvation. Cholesterol metabolism in the starved animal can be depicted as a virtually closed system in both the input from biosynthesis and diet being low or zero and the output likewise being close to zero.

Calcium Metabolism Evaluated by 47Ca kinetics: Estimation of Dermal Calcium Loss

1983 ◽  
Vol 65 (4) ◽  
pp. 415-422 ◽  
Author(s):  
P. Charles ◽  
F. Taagehøj Jensen ◽  
L. Mosekilde ◽  
H. Hvid Hansen
Keyword(s):  
Primary Hyperparathyroidism ◽  
Specific Radioactivity ◽  
Medullary Carcinoma ◽  
Whole Body ◽  
Control Group ◽  
Intestinal Bypass ◽  
Calcium Balance ◽  
Whole Body Counter ◽  
Pool Model ◽  
Calcium Loss

1. Seventy-seven calcium balance and 47Ca turnover studies were performed in normal volunteers (n = 15) and in patients with osteoporosis (n = 12), primary hyperparathyroidism (n = 8), osteogenesis imperfecta (n = 5), medullary carcinoma of the thyroid (n = 4), thyrotoxicosis (n = 2) and intestinal bypass for obesity (n = 11). 2. After intravenous injection of 20 μCi of 47Ca two retention curves of 47Ca were obtained: R1(t) directly measured on a whole-body counter and R2(t) calculated from the cumulated daily excretions of 47Ca in urine and faeces. The data were fitted to a modification of the continuously expanding exchangeable calcium pool model. 3. Dermal calcium loss was estimated from the serum 47Ca specific radioactivity curve and the constantly increasing difference between the two retention curves. The median dermal calcium loss in 77 studies was 1.50 mmol 24 h−1 1.73 m−2 (range 0.13-4.60). 4. The dermal calcium loss might be overestimated by redistribution of tracer or by eventual insufficient collection of urine and faeces. The possible influences of these errors have been evaluated. 5. Patients with primary hyperparathyroidism had a greater (P < 0.02) dermal calcium loss (2.64 mmol; range 0.80–4.50) than a control group (1.38 mmol; range 1.25–2.34).

Interrelationship of Plasma Cholate and Phospholipid Concentrations and Their Resultant Effect on Plasma Cholesterol in Biliary Obstruction

1957 ◽  
Vol 188 (2) ◽  
pp. 337-341 ◽  
Author(s):  
Meyer Friedman ◽  
Sanford Byers
Keyword(s):  
Bile Acid ◽  
Intravenous Injection ◽  
Biliary Obstruction ◽  
Plasma Cholesterol ◽  
Plasma Phospholipid ◽  
Sodium Cholate ◽  
Phospholipid Ratio ◽  
Resultant Effect ◽  
Normal Rat

Elevation of plasma cholate (by intravenous injection of sodium cholate) in both the normal rat and the rat with biliary obstruction was found to lead to an elevation of plasma phospholipid and cholesterol. Experimental elevation of plasma phospholipid (also by injection), however, while leading to an elevation of plasma cholesterol did not elevate the plasma cholate in either the normal or obstructed rat. Furthermore, comparison of the cholesterol-phospholipid ratio obtained in rats by infusion of phosphatide with those observed in rats with biliary obstruction suggests that the plasma phospholipid elevation occurring spontaneously in these latter rats induced the hypercholesteremia observed. In view of these observations, it is suggested the elevation of plasma bile acid occurring in biliary obstruction effects its hypercholesteremic effect by first leading to the elevation of plasma phospholipid. The latter in turn leads to the hypercholesteremia observed.

Changes in Disappearance of Intravenously Administered 47Ca at the Onset of Alimentary Absorption of Unlabelled Calcium

1974 ◽  
Vol 46 (3) ◽  
pp. 311-316
Author(s):  
J. Kocián ◽  
V. Brodan
Keyword(s):  
Gastrointestinal Tract ◽  
Healthy Volunteers ◽  
Intravenous Injection ◽  
Calcium Concentration ◽  
Calcium Absorption ◽  
Specific Radioactivity ◽  
Rapid Decline ◽  
Short Term ◽  
Serum Calcium Concentration ◽  
Temporary Rise

1. Administration of a large amount of unlabelled calcium orally 60 min after intravenous injection of 47Ca leads to a temporary rise of serum specific radioactivity in healthy volunteers. 2. This short-term rise is followed by a more rapid decline and in some instances by oscillations of specific radioactivity. 3. Both these effects could be caused by secretion of thyrocalcitonin resulting from a rise of serum calcium concentration during calcium absorption from the gastrointestinal tract.

scholarly journals Metabolism of Cystine by Merino Sheep Genetically Different in Wool Production IV. Rates of Entry of Cystine Into Plasma, Measured With a Single Intravenous Injection of L- [35S] Cystine, and the Subsequent Incorporation of 35S Into Wool Fibres

1976 ◽  
Vol 29 (6) ◽  
pp. 513 ◽  
Author(s):  
AJ Williams
Keyword(s):  
Intravenous Injection ◽  
Venous Blood ◽  
Specific Radioactivity ◽  
Dietary Treatment ◽  
Pool Size ◽  
Entry Rate ◽  
Merino Sheep ◽  
Fleece Weight ◽  
Dietary Treatments ◽  
Subsequent Incorporation

Ten, 2-year-old Merino ewes from a flock selectively bred for high clean fleece weight (Fleece Plus) and ten from a flock bred for low clean fleece weight (Fleece Minus) were randomly divided between two dietary treatments: 600 or 1100 g/day of pelleted lucerne hay. After 14 weeks, each ewe received an intravenous injection of L-[35Sjcystine (66�4.uCi). Venous blood samples were collected at 15 specified times until 8 h after the injections, and wool fibres were plucked until 65-75 days after the injections. Protein-free filtrates prepared from blood plasma were bulked within sample times for ewes from the same flock and dietary treatment. Equations relating the specific radioactivity of free cystine isolated from the bulked filtrates to time after injection contained three exponential terms. The entry rate and pool size of cystine estimated from these equations were greater in Fleece Minus than in Fleece Plus ewes (by 25 and 44 % respectively for entry rate and pool size). Both traits were also higher in ewes offered 1100 g lucerne/day than in those offered 600 g/day (58�7 v. 33�9 mg/h for entry rate and 19�2 v. 11� 8 mg for pool size). The concentration offree cystine in plasma was greater in ewes offered 1100 g lucerne/day (3�0 v. 2�1 mg/I; P < O� 05), and greater in Fleece Minus ewes (3�0 v. 2�1 mg/I; P < 0�05).

scholarly journals Parameters of the three-pool model of the turnover of plasma cholesterol in normal and hyperlipidemic humans.

1976 ◽  
Vol 57 (1) ◽  
pp. 137-148 ◽  
Author(s):  
F R Smith ◽  
R B Dell ◽  
R P Noble ◽  
D S Goodman
Keyword(s):  
Plasma Cholesterol ◽  
Pool Model
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