PROGRESS AND RATE OF ABSORPTION OF RADIOPHOSPHORUS THROUGH THE INTESTINAL TRACT OF RATS

1961 ◽  
Vol 39 (3) ◽  
pp. 499-503 ◽  
Author(s):  
C. F. Cramer
Keyword(s):  
Absorption Rate ◽  
Intestinal Tract ◽  
Adult Rats ◽  
Effective Absorption ◽  
Normal Absorption ◽  
Two Factors ◽  
Rate Of Absorption ◽  
Effective Contribution

Rates of absorption and the movement of P32 through the intestine of adult rats were measured. These two measurements were combined mathematically to estimate the effective contribution of each segment of the intestinal tract toward normal absorption of phosphorus. All parts of the intestinal tract were able to absorb P32. The rate of absorption was greatest at the duodenum, followed by the jejunum, ileum, colon, and stomach in decreasing order. However, since P32 passed rapidly through the duodenum and jejunum, less material was available to be absorbed, with the result that absorption was less effective in these segments than it was in the ileum. When the progress and rate of absorption was combined quantitatively, the greatest effective absorption was found to occur in the ileum (which absorbed 38% of the total), followed by the duodenum (29%), jejunum (25%), and colon (8%). Two factors were found to limit P32absorption: (a) movement of the isotope into gut segments having slower absorption rate, and (b) decreased absorption of P32 in each gut loop with time. Similar factors had been found previously to limit Sr89 absorption.

Training increases muscle blood flow in rats with peripheral arterial insufficiency

1990 ◽  
Vol 69 (4) ◽  
pp. 1353-1359 ◽  
Author(s):  
H. T. Yang ◽  
R. F. Dinn ◽  
R. L. Terjung
Keyword(s):  
Blood Flow ◽  
Muscle Blood Flow ◽  
Treadmill Running ◽  
Distal Limb ◽  
Adult Rats ◽  
Cage Activity ◽  
Exercise Hyperemia ◽  
Two Factors ◽  
Arterial Insufficiency ◽  
Peripheral Arterial

This study investigated the effect of physical training on muscle blood flow (BF) in rats with peripheral arterial insufficiency during treadmill running. Bilateral stenosis of the femoral artery of adult rats (300-350 g) was performed to reduce exercise hyperemia in the hindlimb but not limit resting muscle BF. Rats were divided into normal sedentary, acute stenosed (stenosed 3 days before the experiment), stenosed sedentary (limited to cage activity), and stenosed trained (run on a treadmill by a progressively intense program, up to 50-60 min/day, 5 days/wk for 6-8 wk). Hindlimb BF was determined with 85Sr- and 141Ce-labeled microspheres at a low (20 m/min) and high treadmill speed (30-40 m/min depending on ability). Maximal hindlimb BF was reduced to approximately 50% normal in the acute stenosed group. Total hindlimb BF (81 +/- 5 ml.min-1.100 g-1) did not change in stenosed sedentary animals with 6-8 wk of cage activity, but a redistribution of BF occurred within the hindlimb. Two factors contributed to a higher BF to the distal limb muscle of the trained animals. A redistribution BF within the hindlimb occurred in stenosed trained animals; distal limb BF increased to approximately 80% (P less than 0.001) of the proximal tissue. In addition, an increase in total hindlimb BF with training indicates that collateral BF has been enhanced (P less than 0.025). The associated increase in oxygen delivery to the relatively ischemic muscle probably contributed to the markedly improved exercise tolerance evident in the trained animals.

Function curve of the membranes that regulate amniotic fluid volume in sheep

2005 ◽  
Vol 289 (1) ◽  
pp. H146-H150 ◽  
Author(s):  
Job Faber ◽  
Debra Anderson ◽  
Roger Hohimer ◽  
Qin Yang ◽  
George Giraud ◽  
...  
Keyword(s):  
Amniotic Fluid ◽  
Absorption Rate ◽  
Plasma Renin ◽  
Fluid Volume ◽  
Natural Rate ◽  
Fetal Plasma ◽  
Amniotic Fluid Volume ◽  
Urine Production ◽  
Rate Of Absorption ◽  
Vascular Catheters

Seven singleton 120-day fetal lambs were prepared with a shunt from the lung to the gastric end of the esophagus, a bladder catheter, and multiple amniotic fluid and vascular catheters. The urachus was ligated. Beginning 7 days later, amniotic fluid volumes were determined by drainage, followed by replacement with 1 liter of lactated Ringer (LR) solution. Urine flow into the amnion was measured continuously. In 14 of 27 experiments, amniotic fluid volumes were determined again 2 days after the inflow into the amnion had consisted of urine only and in 13 experiments after the inflow of urine had been supplemented by an intraamniotic infusion of LR solution. Intramembranous absorption was calculated from the inflows and the changes in volume between the beginning and end of each experiment. The relations between absorption rate and amniotic fluid volume, the “function curves,” were highly individual. Urine production during the infusion of LR solution did not decrease, fetal plasma renin activity decreased ( P < 0.001), and amniotic fluid volume increased by 140% [SE (27%), P < 0.005], but the increase in the amniochorionic absorption rate of 411% [SE (48%), P < 0.001] was greater ( P < 0.005) than the increase in volume. Each of the seven fetuses was proven capable of an average intramembranous absorption rate that exceeded 4.5 liters of amniotic fluid per day. During the infusion of LR solution, the increase in the rate of absorption matched the rate of infusion (both in ml/h), with a regression coefficient of 0.75 ( P < 0.001). Thus, even for large amniotic fluid volumes, volume is not limited by the absorptive capacity of the amniochorion, and, at least in these preparations, the position of the function curve and not the natural rate of inflow was the major determinant of resting amniotic fluid volume.

scholarly journals Studies on antagonism.―I. The effect of the presence of salts of monovalent, divalent, and trivalent kations on the intake of calcium and ammonium ions by potato tuber tissue

1933 ◽  
Vol 112 (778) ◽  
pp. 451-472 ◽  
Keyword(s):  
Chemical Analysis ◽  
Physical Properties ◽  
Absorption Rate ◽  
Initial Rate ◽  
Final Position ◽  
Ammonium Ions ◽  
Conductivity Method ◽  
Tuber Tissue ◽  
Rate Of Absorption ◽  
The Subject

The intake of salts by storage tissues has been worked out at some length by Stiles using both the conductivity method and chemical analysis to determine the alteration in concentration of the solution supplied to the tissue. Results of these investigations as well as those of other workers on the subject point to the fact that salts are not taken in as such, but as their constituent ions, which may be absorbed to a very different degree. Stiles (1924) found that the ions were absorbed comparatively rapidly at first, for a period lasting up to 10 hours, after which there was a gradual falling off in the absorption rate so that after 24 hours absorption was only proceeding very slowly. It was also suggested that the initial rate of absorption depended more on the physical properties of the ions, such as their mobility and the coefficients of diffusion of their salts, and bore, it was found, no relationship to the final position of equilibrium (Stiles, 1919).

Rate of Absorption of Glucose from the Intestinal Tract of the Rabbit

1934 ◽  
Vol 32 (2) ◽  
pp. 323-326
Author(s):  
E. M. MacKay ◽  
H. C. Bergman ◽  
R. H. Barnes
Keyword(s):  
Intestinal Tract ◽  
Rate Of Absorption

scholarly journals THE RATE OF ABSORPTION OF GLUCOSE FROM THE INTESTINAL TRACT

1933 ◽  
Vol 101 (2) ◽  
pp. 453-462 ◽  
Author(s):  
Eaton M. MacKay ◽  
H.C. Bergman
Keyword(s):  
Intestinal Tract ◽  
Rate Of Absorption

LEVELS OF RADIOACTIVITY IN TISSUES AND IN EXPIRED CARBON DIOXIDE AFTER ADMINISTRATION OF 1-C14-LABELLED PALMITIC ACID, 2-C14-LABELLED ERUCIC ACID, OR 2-C14-LABELLED NERVONIC ACID TO RATS

1962 ◽  
Vol 40 (9) ◽  
pp. 1229-1238 ◽  
Author(s):  
K. K. Carroll
Keyword(s):  
Erucic Acid ◽  
Palmitic Acid ◽  
Intestinal Tract ◽  
Nervonic Acid ◽  
Adult Rats ◽  
Brain Lipids ◽  
Tail Vein ◽  
Body Tissues ◽  
Tissue Lipids ◽  
Old Rats

Palmitic acid -1-C14, erucic acid -2-C14, and nervonic acid -2-C14 were administered to young adult rats by mouth, and levels of radioactivity in various body tissues and in respiratory CO2 were determined. After [Formula: see text] hours about 20% of the label from palmitic acid and erucic acid and 30% from nervonic acid was still in the intestinal tract but after 24 hours less than 5% remained. At [Formula: see text] or 24 hours, tissue lipids of rats given palmitic acid generally contained a higher percentage of radioactivity administered than lipids from corresponding tissues of rats given erucic acid or nervonic acid. Very little radioactivity was found in brain lipids of either adult or 12-day-old rats given the labelled acids. The fatty acids were also given to adult rats by tail-vein injection and highest activities were again observed in tissue lipids of rats given palmitic acid.When given by mouth, palmitic acid contributed more radioactivity to respiratory CO2 during the first 6 hours than erucic acid or nervonic acid, and peak activities did not occur until 2 to 3 hours after administration. When given by tail vein, erucic acid and nervonic acid contributed more activity to respiratory CO2 than palmitic acid. Highest activities were observed during the first hour but the peak was reached somewhat later in rats given erucic acid or nervonic acid.

Rates of triolein absorption in suckling and adult rats

1989 ◽  
Vol 257 (5) ◽  
pp. G823-G829 ◽  
Author(s):  
C. A. Flores ◽  
S. A. Hing ◽  
M. A. Wells ◽  
O. Koldovsky
Keyword(s):  
Gastrointestinal Tract ◽  
Oral Administration ◽  
Age Groups ◽  
Adult Rats ◽  
Old Adults ◽  
Suckling Rats ◽  
The Third ◽  
Triton Wr 1339 ◽  
Rate Of Absorption ◽  
High Dietary Intake

To determine the extent to which suckling animals differ from adults in their capacity to absorb fat, we compared the rate of absorption of orally administered [14C]triolein in 11- to 12-day-old suckling rats with that of 10-wk-old adults by three distinct methods. In the first, the rate of [14C]triolein disappearance was determined by quantitating substrate remaining in the gastrointestinal tract after oral administration. In the second, 14CO2 expiration in breath was measured continuously for 6 h after an identical feeding. In the third, intestinal triglyceride output was estimated by the lipoprotein lipase inhibitor, Triton WR-1339. Triolein disappearance, 14CO2 excretion, and intestinal triglyceride output were two- to threefold higher in suckling rats compared with adults (P less than 0.01, P less than 0.0001, and P less than 0.01, respectively). There was also a highly significant linear relationship between 14CO2 excretion and both triolein disappearance and intestinal triglyceride output for both age groups (P less than 0.0001 and P less than 0.003, respectively). These data show that consistent with its high dietary intake, the suckling rat can absorb triolein at rates significantly higher than the adult.

Mathematical Modeling of Drug Release from Spherical Drug Particles: Analysis of the Effect of Absorption Rate on Drug Release Rate

2009 ◽  
Vol 4 (5) ◽  
Author(s):  
Norman W Loney ◽  
Ramana Susarla
Keyword(s):  
Drug Release ◽  
Absorption Rate ◽  
Release Kinetics ◽  
Closed Form Solution ◽  
Form Solution ◽  
Proposed Model ◽  
Significant Difference ◽  
Rate Of Absorption ◽  
Kinetics Of ◽  
And Diffusion

A closed form solution has been obtained for the release kinetics of a solute from a spherical drug matrix into a finite volume of liquid, taking into account the effect of rate of absorption. The proposed model results clearly show the effect of the absorption rate constant on the rate of drug release. The obtained results are compared with the experimental data and diffusion-only model results. There is a significant difference in the release profile when the rate of absorption of drug is slow. The most important feature of the mathematical relationship between the liquid concentration verses time is its ability to predict change in the performance of the drug by manipulating the parameters of the equation. These parameters include the initial concentration of the drug, the radius of the drug and diffusivity of the drug in the solid to name a few. Therefore, a substantial number of experiments can be eliminated when the optimal performance of a drug is sought after.

Simultaneous Analysis of the Single and Multiple Dose Pharmacokinetics of the Non-Steroidal Anti-Inflammatory, Alclofenac

1979 ◽  
Vol 7 (4) ◽  
pp. 253-262
Author(s):  
Lawrence T Sennello ◽  
Robert C Sonders ◽  
William G Jochimsen ◽  
Nadav Friedmann
Keyword(s):  
Half Life ◽  
Absorption Rate ◽  
Study Drug ◽  
Compartment Model ◽  
Multiple Dosing ◽  
Healthy Adult Male ◽  
Dosing Regimens ◽  
Rate Of Absorption ◽  
Multiple Dose Pharmacokinetics ◽  
Single Set

Two clinical studies were conducted to study the pharmacokinetics of alclofenac in healthy adult male volunteers when the drug was administered in both single and multiple dosing regimens. The first study involved the participation of thirty-two subjects, each of whom received single 500 mg and 1000 mg oral doses of alclofenac, using a complete crossover experimental design. The second study involved the participation of sixteen subjects, eight of whom received a 500 mg dose, and eight of whom received a 1000 mg dose of alclofenac every eight hours for ninety-six consecutive hours (four days) with no crossover. In the first study, plasma alclofenac levels were monitored for ten hours post-dosing, while in the second study, drug levels were monitored for four and one-half days (i.e. through twelve hours after the last dose). Initially, using the programme NONLIN, single dose data were fit to a bi-exponential equation, with output from these fits serving as initial estimates for a second fit to the same equation. The results of these second fits were then used as initial estimates to fit the multiple dosing data to a multiple dosing one-compartment model with first order absorption and elimination. Finally, all sets of data were simultaneously fit to the one-compartment open model, with both single and multiple dosing, in an attempt to obtain a uniform interpretation, with a single set of parameters that would adequately describe the plasma alclofenac levels to be expected with a variety of dosing regimens. It was found that the kinetics did not significantly change upon going from single to multiple dosing, and that with the exception of the apparent absorption rate constant, a single set of parameters adequately described all the data collected. The rate of absorption seemed to be somewhat dose-dependent at these levels, being slower after 1000 mg doses than after 500 mg doses. For this reason, the simultaneous fitting program was allowed to estimate different absorption rate constants for the 500 mg and 1000 mg doses. The results of these simultaneous analyses were: Vol Distribution/Fraction Abs = 6.56 Litres Absorption Half-Life (500 mg) = 14 Minutes Absorption Half-Life (1000 mg) = 30 Minutes Elimination Half-Life = 2.1 Hours Absorption Lag Time = 14 Minutes

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