ABSORPTION OF BILIARY THYROXINE FROM LOOPS OF SMALL INTESTINE

1965 ◽  
Vol 43 (5) ◽  
pp. 801-807 ◽  
Author(s):  
W. H. Cottle ◽  
A. T. Veress
Keyword(s):  
Small Intestine ◽  
Free Thyroxine ◽  
Glucuronide Conjugate ◽  
Rate Of Absorption

The absorption of labelled thyroxine and its glucuronide conjugate from loops of small intestine has been studied in rats. Free thyroxine was found to be more readily absorbed than its conjugate, suggesting that formation of the conjugate by the liver facilitates excretion of the hormone. No difference was found between the rate of absorption of these materials from loops prepared in cold-acclimated rats and from those prepared in warm-acclimated rats. Labelled D-thyroxine added to bile was found to be absorbed as readily as added L-thyroxine.

scholarly journals The Effect of Potassium on the Intestinal Transport of Glucose

1966 ◽  
Vol 50 (1) ◽  
pp. 113-128 ◽  
Author(s):  
T. Z. Csáky ◽  
P. M. Ho
Keyword(s):  
Small Intestine ◽  
Specific Activity ◽  
Lactic Acid Production ◽  
Sugar Transport ◽  
Intestinal Transport ◽  
Intestinal Lumen ◽  
High K ◽  
Rate Of Absorption ◽  
Specific Sugar

The rate of absorption of glucose, galactose, and 3-0-methylglucose was studied in the rat's small intestine perfused in situ with isosmotic solutions containing these sugars and Na2SO4 or K2SO4. The presence of high [K+] in the lumen enhances absorption of glucose but not that of galactose or of 3-0-methylglucose. The potassium stimulation is apparent at higher glucose concentrations where primarily carrier-mediated diffusion is involved in the translocation. In this case potassium stimulates transport even if it is the only cation in the lumen. The potassium-stimulated intestine produces more glycogen with higher specific activity than the control gut. Lactic acid production by the intestine is markedly enhanced if the intestinal lumen is perfused with a solution containing glucose and high [K+]. It is concluded that potassium does not affect permeability or the specific sugar transport system of the gut, but enhances intracellular metabolic disappearance of glucose thereby creating a larger luminal intracellular concentration gradient which in turn enhances the rate of carrier-facilitated entry.

Ammonia in the large intestine of herbivores

1971 ◽  
Vol 26 (2) ◽  
pp. 135-145 ◽  
Author(s):  
J. F. Hecker
Keyword(s):  
Small Intestine ◽  
Large Intestine ◽  
Free Amino ◽  
Amino Nitrogen ◽  
Ammonia Concentration ◽  
Intestinal Contents ◽  
Rate Of Absorption ◽  
Small Intestinal

1. The object was toinvestigate the importance of urea a source of ammonia in the large intestine of herbivores. Urea was present in small intestinal contents of slaughtered horses in concentrations similar to those in blood but, in the small intestine of salughtered sheep, the urea was less than in blooc.2. There was little ammonia in small intestinal contents of slaughtered horses but consider-able ammonia was present in small intestinal contents of slaughtered sheep. The ammonia in small intestinal contents of the slaughtered sheep was probably formed from urea, as ileal con-tents taken from a sheep with an ileal cannula contained considerable urea and little ammonia.3. The ammonia concentration in caecal contents of sheep was related to the concentration of urea in blood except when ileal contents were prevented from entering the caecum.4. Ileal digesta of sheep contained more free amino nitrogen than did caecal digesta.5. Ammonia was absorbed more rapidly than water from the caecum of sheep. The rate of absorption was related to the concentration of ammonia in the caecum.

Stimulation of abomasal flow in sheep with buffer infusions per abomasum and effects of same on certain aspects of intestinal function

1988 ◽  
Vol 39 (6) ◽  
pp. 1121 ◽  
Author(s):  
DE Margan
Keyword(s):  
Small Intestine ◽  
Volatile Fatty Acids ◽  
Sodium Citrate ◽  
Mineral Salts ◽  
Proximal Half ◽  
Abomasal Infusion ◽  
Gastric Juice Secretion ◽  
Rate Of Absorption ◽  
Flow Changes ◽  
Extent Of Absorption

Infusion into the abomasum of sheep of a mixture of volatile fatty acids partially neutralized with sodium hydroxide (VFA salts) markedly increased the rates of flow of liquor and chloride from the abomasum to the small intestine; buffered mineral salts comprising sodium bicarbonate, sodium citrate and either disodium or dipotassium orthophosphate consistently produced a similar but smaller response. Thcre was little or no effect of the infusions on rumen or omasal outflow. By contrast, infusion of VFA in acid form had no effect on abomasal liquor and chloride flow and the infusion of sodium chloride did not effect liquor flow. The pH of abomasal digesta either decreased slightly or was unchanged when VFA salts wcre infused, but increased with infusion of mineral buffer salts. It is concluded that gastric secretion is markedly affected by the buffering capacity of the digesta entering the abomasum. The VFA entering the abomasum in digesta were estimated to be responsible for the secretion of as much as 60% of the chloride secreted into the organ. High rates of abomasal secretion, induced by intra-abomasal infusion of VFA salts, increased both (i) the amount of digesta in the abomasum and small intestine, (ii) the extent of absorption of calcium and magnesium distal to the omasum, and (iii) absorption from the small intestine of water, chloride and VFA, while decreasing (i) the pH of digesta in some sections of the small intestine and (ii) marker residence time in the proximal half of the small intestine. The rates of flow of both liquor and chloride from the abomasum, together with pH of abomasal digesta, progressively increased with age in animals aged 6, 10 and 30 months; they were still larger in other animals aged 54 months. By contrast, no consistent trends with age were observed with VFA and chloride concentrations in rumen liquor or the flow of metabolites from the rumen. The flow changes are suggested to be the result of changes in gastric juice secretion with age, stimulated at least in part by a corresponding decrease in the rate of absorption of buffering substances in the omasum and/or abomasum.

Zinc absorption in human small intestine

1989 ◽  
Vol 256 (1) ◽  
pp. G87-G91 ◽  
Author(s):  
H. H. Lee ◽  
A. S. Prasad ◽  
G. J. Brewer ◽  
C. Owyang
Keyword(s):  
Small Intestine ◽  
Intestinal Absorption ◽  
Transport Process ◽  
Zinc Absorption ◽  
Perfusion Technique ◽  
Enhanced Absorption ◽  
Human Small Intestine ◽  
Entire Small Intestine ◽  
Rate Of Absorption ◽  
Zinc Concentrations

We determined the intestinal site of zinc absorption in humans and investigated the interaction between intestinal absorption of zinc and other solutes using the triple-lumen steady-state perfusion technique. Twenty-one healthy subjects participated in the study. During intestinal perfusion of a balanced electrolyte solution containing 0.1 mM zinc acetate, zinc absorption occurred throughout the entire small intestine. However, the jejunum had the highest rate of absorption (357 +/- 14 nM.min-1.40 cm-1) compared with the duodenum (230 +/- 33 nM.min-1.40 cm-1) and ileum (84 +/- 10 nM.min-1.40 cm-1). Over a range of zinc concentrations infused into the jejunum (0.1, 0.9, and 1.8 mM) there were linear increases in the rate of zinc absorption (P less than 0.05). Intestinal absorption of zinc was significantly stimulated by the addition of glucose (20 mM). Zinc absorption increased from 459 +/- 39 to 582 +/- 45 nM.min-1.40 cm-1 (P less than 0.05). Conversely, zinc (0.9 mM) also enhanced the absorption of glucose, which was increased from 293 +/- 43 to 447 +/- 27 microM.min-1.40 cm-1 (P less than 0.05). The enhanced absorption of zinc or glucose was not accompanied by any increase in absorption of water and sodium. In contrast, increasing the concentration of zinc in the perfusate resulted in decreased absorption of sodium and water in a dose-related manner. In conclusion, our study demonstrated that zinc absorption is concentration dependent and occurs throughout the small intestine. The jejunum has the highest rate of absorption of zinc. The interactions between absorption of zinc and other solutes suggest that the transport process of zinc is carrier mediated.

scholarly journals Effects of wheat-flour and oat mill fractions on jejunal flow, starch degradation and absorption of glucose over an isolated loop of jejunum in pigs

1994 ◽  
Vol 72 (2) ◽  
pp. 299-313 ◽  
Author(s):  
Helle N. Johansen ◽  
K. E. Bach Knudsen
Keyword(s):  
Small Intestine ◽  
Gastric Emptying ◽  
Wheat Flour ◽  
Starch Content ◽  
Mean Transit Time ◽  
Glucose Absorption ◽  
Major Influence ◽  
Starch Degradation ◽  
Proximal Small Intestine ◽  
Rate Of Absorption

The effect of cereal-based diets varying in dietary fibre (DF) on gastric emptying and glucose absorption over an isolated loop of jejunum was studied in four pigs fitted with two sets of re-entrant cannulas. The pigs were fed on either a wheat-flour diet or three diets based on oat flour (endosperm), rolled oats or oat bran containing different amounts of soluble DF. Mean transit time (MTT) of liquid estimated from the output from the first jejunal cannula was significantly higher with the two diets having the highest DF content, but MTT of dry matter (DM), starch, xylose and neutral non-starch polysaccharides (nNSP) was not correlated directly to the DF content of the diet. DF had a stimulatory effect on secretion of gastrointestinal juices, but the effect was not linearly correlated with the DF content of the diet. Starch was significantly degraded in digesta collected within 30 min after feeding with malto-oligosaccharides accounting for 140–147 g/kg total starch. The degradation was more extensive with higher DF and lower starch content of the diet. However, taking into account the differences in jejunal flow, the amount of malto-oligosaccharides available for absorption in the first 0.5 h decreased with higher levels of DF in the oat-based diets. The absorption of glucose from the isolated loop was 18–34 g/m intestine over an 8 h period with no significant differences between diets. This corresponded to a non-significant decrease in recovery of starch from 0.91 to 0.82 with increasing levels of DF and decreasing levels of starch in the diet. This suggests that the capacity for absorption of large doses of starch entering the proximal small intestine after ingestion of a carbohydrate-rich cereal-based diet has a major influence on the absorption at this site. Consequently any effect of DF on glucose absorption may be exerted either through the rate of gastric emptying or by impaired rate of absorption more distal in the small intestine and not by displacement of the site for starch absorption.

Comparison of the Absorption and Destruction of the Lactone and Salt Form of Glucuronic Acid by Dogs

1956 ◽  
Vol 188 (1) ◽  
pp. 54-60
Author(s):  
F. A. Buckeridge ◽  
Smith Freeman
Keyword(s):  
Small Intestine ◽  
Plasma Concentration ◽  
Glucuronic Acid ◽  
The Body ◽  
Limiting Factor ◽  
Salt Form ◽  
Ph Values ◽  
Rate Of Absorption ◽  
The Stability

Comparative studies were made on the fate of d-glucuronolactone and d-glucuronate in dogs. The studies included: a) measurement of the rate of conversion of the lactone into the salt form at various ph values ranging from 2.0 to 7.4; b) measure of the rate of absorption from isolated loops of small intestine; c) determination of the blood plasma concentration in relation to intestinal absorption of the two forms of glucuronic acid in normal, Eck fistula and nephrectomized animals; d) the stability and magnitude of the plasma values were determined following the intravenous injection of the lactone or salt form of glucuronic acid into nephrectomized dogs. From the foregoing studies, it was determined that: a) glucuronolactone is rapidly converted into glucuronate at the ph of plasma; b) glucuronolactone is absorbed from the small intestine much more rapidly than is glucuronate; c) absorbed glucuronolactone is metabolized rapidly while glucuronate appears to be relatively inert in the body and to occupy a space similar to that of inulin. The limiting factor in the metabolism of glucuronolactone is the rate of its conversion into the salt form.

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