Bile salt absorption in killifish intestine

1987 ◽  
Vol 253 (6) ◽  
pp. G730-G736 ◽  
Author(s):  
R. E. Honkanen ◽  
J. S. Patton
Keyword(s):  
Bile Salt ◽  
Active Transport ◽  
Transport System ◽  
Bile Salts ◽  
Critical Micellar Concentration ◽  
Distal Intestine ◽  
Salt Uptake ◽  
Salt Absorption ◽  
Active Transport System

Bile salt absorption was examined in vitro using entire small intestines from the killifish Fundulus heteroclitus. Intestines were everted over a glass rod and incubated in solutions containing 10 nM to 20 mM bile salts. After rinsing and correcting for the adherent fluid space, uptake rates and bile salt concentrations in the tissue were determined. The distal intestine contained a Na+-dependent active transport system for bile salt uptake with an apparent Vmax for taurocholate and cholate of 1.4 and 2.3 nmol.min-1.mg dry wt-1 (Km = 117 and 357 microM), respectively. At low concentrations (10 nM to 500 microM), absorption occurred almost exclusively (greater than 84%) in the distal intestine. However, at concentrations of 1 mM and above, bile salt absorption in the middle and proximal regions equaled that in the distal intestine. Thus, although an active transport system makes the distal intestine more efficient in absorbing bile salts, passive absorption appears to account for a significant amount of bile salt uptake at concentrations above the critical micellar concentration. The presence of oleic acid did not significantly affect bile salt uptake.

scholarly journals Characteristics of bile salt uptake into skate hepatocytes

1994 ◽  
Vol 299 (3) ◽  
pp. 665-670 ◽  
Author(s):  
G Fricker ◽  
V Dubost ◽  
K Finsterwald ◽  
J L Boyer
Keyword(s):  
Substrate Specificity ◽  
Bile Salt ◽  
Transport System ◽  
Bile Salts ◽  
Organic Anion ◽  
Anion Transport ◽  
Organic Anion Transport ◽  
Salt Uptake ◽  
Anion Transport System ◽  
Alpha 7

The substrate specificity for the transporter that mediates the hepatic uptake of organic anions in freshly isolated hepatocytes of the elasmobranch little skate (Raja erinacea) was determined for bile salts and bile alcohols. The Na(+)-independent transport system exhibits a substrate specificity, which is different from the specificity of Na(+)-dependent bile salt transport in mammals. Unconjugated and conjugated di- and tri-hydroxylated bile salts inhibit uptake of cholyltaurine and cholate competitively. Inhibition is significantly greater with unconjugated as opposed to glycine- or taurine-conjugated bile salts. However, the number of hydroxyl groups in the steroid moiety of the bile salts has only minor influences on the inhibition by the unconjugated bile salts. Since the transport system seems to represent an archaic organic-anion transport system, other anions, such as dicarboxylates, amino acids and sulphate, were also tested, but had no inhibitory effect on bile salt uptake. To clarify whether bile alcohols, the physiological solutes in skate bile, share this transport system, cholyltaurine transport was studied after addition of 5 beta-cholestane-3 beta,5 alpha,6 beta-triol, 5 alpha-cholestan-3 beta-ol and 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha-triol. These bile alcohols inhibit cholyltaurine uptake non-competitively. In contrast, uptake of 5 beta-cholestane-3 alpha,7 alpha,12 alpha-triol, which is Na(+)-independent, is not inhibited by cholyltaurine. The findings further characterize a Na(+)-independent organic-anion transport system in skate liver cells, which is not shared by bile alcohols and has preference for unconjugated lipophilic bile salts.

Effect of intestinal resection on bile salt absorption in dogs

1965 ◽  
Vol 208 (2) ◽  
pp. 363-369 ◽  
Author(s):  
M. R. Playoust ◽  
Leon Lack ◽  
I. M. Weiner
Keyword(s):  
Bile Salt ◽  
Bile Salts ◽  
Enterohepatic Circulation ◽  
Sodium Taurocholate ◽  
Intestinal Resection ◽  
High Fat ◽  
Salt Absorption ◽  
Complete Failure ◽  
Fat Meal

The efficiency of intestinal absorption of bile salts was evaluated by studying the rate of disappearance of radioactivity from the bile of dogs after the intravenous administration of sodium taurocholate-24-C14. Bile was sampled through an indwelling tube in the gall bladder. One day after a high-fat meal normal dogs retained 48% of the radioactivity; dogs with resection of the jejunum retained 48%, whereas those with resection of the ileum retained only 3% in the bile. This is consistent with previous observations that the ileum is the site of bile salt absorption in vitro and in anesthetized animals. Animals with resection of the ileum exhibited significant steatorrhea; however, three-fourths of the ingested fat was absorbed in spite of almost complete failure to absorb bile salts. This indicates that fat and bile salts are not normally absorbed together. Elimination of enterohepatic circulation of bile salts by resection of the ileum contributes to the observed steatorrhea.

scholarly journals Interaction of the New Ketolide ABT-773 (Cethromycin) with Human Polymorphonuclear Neutrophils and the Phagocytic Cell Line PLB-985 In Vitro

2004 ◽  
Vol 48 (4) ◽  
pp. 1096-1104 ◽  
Author(s):  
Marie Thérèse Labro ◽  
Houria Abdelghaffar ◽  
Catherine Babin-Chevaye
Keyword(s):  
Cell Line ◽  
Active Transport ◽  
Transport System ◽  
Culture Conditions ◽  
Polymorphonuclear Neutrophils ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Erythromycin A ◽  
Active Transport System

ABSTRACT A classical velocity centrifugation technique was used to study the in vitro uptake of the new ketolide ABT-773 by human polymorphonuclear neutrophils (PMNs) and a myelomonoblastic cell line, PLB-985, which can be differentiated into PMNs under certain culture conditions, compared to that of HMR 3004. ABT-773 was rapidly taken up by PMNs (cellular concentration to extracellular concentration ratio [C/E], about 34 at 30 s and up to 207 at 5 min), and uptake plateaued from 30 to 180 min (C/E, about 300). ABT-773 was accumulated significantly better than HMR 3004 from 5 to 180 min. Nondifferentiated PLB-985 cells (ND-PLB) accumulated significantly less ABT-773 and HMR 3004 than PMNs and PLB-985 cells differentiated into PMNs (D-PLB). Whatever the cell type and in contrast to the results obtained with HMR 3004, ABT-773 was mainly located in the cytosol (about 75%) and was rapidly released from loaded cells (about 40% at 5 min), followed by a plateau, likely owing to avid reuptake. Verapamil and H89, an inhibitor of protein kinase A, increased drug efflux. Uptake was sensitive to external pH, and the activation energy was moderate (about 50 kJ/mol). The existence of an active transport system on the PMN membrane was suggested by the following findings: concentration-dependent and saturable uptake (V max, about 10 000 ng/2.5 × 106 PMNs/5 min; Km , about 60 μg/ml) the inhibitory effects of PMN activators or inhibitors (phorbol myristate acetate, verapamil, Ni2+) and the significantly decreased levels of accumulation by killed cells and cells treated at low temperatures. In addition, various macrolides impaired ABT-773 uptake, contrary to the findings for the quinolone levofloxacin. ND- and D-PLB also presented saturation kinetics that defined an active transport system (V max and Km values were similar to those obtained with PMNs), but the activation pathway of the carrier system did not seem to be fully functional in ND-PLB. As has been observed with other erythromycin A derivatives, ABT-773 impaired oxidant production by phagocytes in a time- and concentration-dependent manner. These data extend our previous results on the existence of an active transport system common to all macrolides and ketolides, at least in PMNs.

Jejunum is more important than terminal ileum for taurocholate absorption in rats

1983 ◽  
Vol 244 (5) ◽  
pp. G507-G514 ◽  
Author(s):  
C. McClintock ◽  
Y. F. Shiau
Keyword(s):  
Bile Salt ◽  
Active Transport ◽  
Terminal Ileum ◽  
Enterohepatic Circulation ◽  
In Vivo Studies ◽  
Proximal Jejunum ◽  
Flux Chamber ◽  
Salt Absorption ◽  
Active Transport System

The terminal ileum, with its active transport system, is considered the major site of bile salt absorption. However, earlier studies used bile salt concentrations below physiological levels and may not apply in vivo. Analysis of these studies shows that ileal active transport cannot account for total bile salt recovery. To reevaluate bile salt absorption in rats, we used four preparations and physiological bile salt concentrations. Studies with intestinal sacs showed that, above critical micellar concentration, uptake of taurocholate (TC) was equal in both jejunum and ileum and linear with respect to concentration. A similar pattern was observed in studies of mucosal-to-serosal TC transport using a flux chamber. In vivo studies in anesthetized rats showed approximately 30% of TC absorbed from proximal jejunum and appearing in bile when the bolus had traversed only half the intestine. In unanesthetized fed rats, 60% of TC appeared in bile before the bolus reached distal ileum. Because luminal concentrations of TC are highest proximally, passive absorption by the proximal intestine is mainly responsible for conserving TC within the enterohepatic circulation. Ileal active transport is more efficient at low concentrations and absorbs the TC remaining after proximal absorption.

scholarly journals Solubilization of lipids from hamster bile-canalicular and contiguous membranes and from human erythrocyte membranes by conjugated bile salts

1987 ◽  
Vol 242 (3) ◽  
pp. 825-834 ◽  
Author(s):  
J M Graham ◽  
T C Northfield
Keyword(s):  
Bile Salt ◽  
Human Erythrocyte ◽  
Bile Salts ◽  
Critical Micellar Concentration ◽  
The Other ◽  
Erythrocyte Membranes ◽  
Other Hand ◽  
Liquid Crystal System ◽  
Phospholipid Ratio

We have demonstrated in vitro the efficacy of the taurine-conjugated dihydroxy bile salts deoxycholate and chenodeoxycholate in solubilizing both cholesterol and phospholipid from hamster liver bile-canalicular and contiguous membranes and from human erythrocyte membrane. On the other hand, the dihydroxy bile salt ursodeoxycholate and the trihydroxy bile salt cholate solubilize much less lipid. The lipid solubilization by the four bile salts correlated well with their hydrophobicity: glycochenodeoxycolate, which is more hydrophobic than the tauro derivative, also solubilized more lipid. All the dihydroxy bile salts have a threshold concentration above which lipid solubilization increases rapidly; this correlates approximately with the critical micellar concentration. The non-micelle-forming bile salt dehydrocholate solubilized no lipid at all up to 32 mM. All the dihydroxy bile acids are much more efficient at solubilizing phospholipid than cholesterol. Cholate does not show such a pronounced discrimination. Lipid solubilization by chenodeoxycholate was essentially complete within 1 min, whereas that by cholate was linear up to 5 min. Maximal lipid solubilization with chenodeoxycholate occurred at 8-12 mM; solubilization by cholate was linear up to 32 mM. Ursodeoxycholate was the only dihydroxy bile salt which was able to solubilize phospholipid (although not cholesterol) below the critical micellar concentration. This similarity between cholate and ursodeoxycholate may reflect their ability to form a more extensive liquid-crystal system. Membrane specificity was demonstrated only inasmuch as the lower the cholesterol/phospholipid ratio in the membrane, the greater the fractional solubilization of cholesterol by bile salts, i.e. the total amount of cholesterol solubilized depended only on the bile-salt concentration. On the other hand, the total amount of phospholipid solubilized decreased with increasing cholesterol/phospholipid ratio in the membrane.

On the structural organization of biological pumps and channels

1984 ◽  
Vol 42 ◽  
pp. 138-141
Author(s):  
G. Zampighi ◽  
M. Kreman
Keyword(s):  
Active Transport ◽  
Transport System ◽  
Plasma Membranes ◽  
Transport Proteins ◽  
Molecular Organization ◽  
Passive Transport ◽  
Concentration Gradients ◽  
Cell Functions ◽  
Natural Concentration ◽  
Active Transport System

The plasma membranes of most animal cells contain transport proteins which function to provide passageways for the transported species across essentially impermeable lipid bilayers. The channel is a passive transport system which allows the movement of ions and low molecular weight molecules along their concentration gradients. The pump is an active transport system and can translocate cations against their natural concentration gradients. The actions and interplay of these two kinds of transport proteins control crucial cell functions such as active transport, excitability and cell communication. In this paper, we will describe and compare several features of the molecular organization of pumps and channels. As an example of an active transport system, we will discuss the structure of the sodium and potassium ion-activated triphosphatase [(Na+ +K+)-ATPase] and as an example of a passive transport system, the communicating channel of gap junctions and lens junctions.

scholarly journals Actions of external hypertonic urea, ADH, and theophylline on transcellular and extracellular solute permeabilities in frog skin.

1975 ◽  
Vol 65 (5) ◽  
pp. 599-615 ◽  
Author(s):  
L J Mandel
Keyword(s):  
Linear Relationship ◽  
Active Transport ◽  
Transport System ◽  
Frog Skin ◽  
Open Circuit Potential ◽  
Open Circuit ◽  
Solute Permeability ◽  
Parallel Lines ◽  
Paracellular Pathways ◽  
Active Transport System

Increases in transepithelial solute permeability were elicited in the frog skin with external hypertonic urea, theophylline, and vasopressin (ADH). In external hypertonic urea, which is known to increase the permeability of the extracellular (paracellular) pathway, the unidirectional transepithelial fluxes of Na (passive), K, Cl, and urea increased substantially while preserving a linear relationship to each other. The same linear relationship was also observed for the passive Na and urea fluxes in regular Ringer and under stimulation with ADH or 10 mM theophylline, indicating that their permeation pathway was extracellular. A linear relationship between Cl and urea fluxes could be demonstrated if the skins were separated according to their open circuit potentials; parallel lines were obtained with increasing intercepts on the Cl axis as the open circuit potential decreased. The slopes of the Cl vs. urea lines were not different from that obtained in external hypertonic urea, indicating that this relationship described the extracellular movement of Cl. The intercept on the ordinate was interpreted as the contribution from the transcellular Cl movement. In the presence of 0.5 mM theophylline or 10 mU/ml of ADH, mainly the transcellular movement of Cl increased, whereas 10 mM theophylline caused increases in both transcellular and extracellular Cl fluxes. These and other data were interpreted in terms of a possible intracellular control of the theophylline-induced increase in extracellular fluxes. The changes in passive solute permeability were shown to be independent of active transport. The responses of the active transport system, the transcellular and paracellular pathways to theophylline and ADH could be explained in terms of the different resulting concentrations of cyclic 3'-5'-AMP produced by each of these substances in the tissue.

scholarly journals Studies on the interactions between bile salts and food emulsifiers under in vitro duodenal digestion conditions to evaluate their bile salt binding potential

2019 ◽  
Vol 174 ◽  
pp. 493-500 ◽  
Author(s):  
Julieta N. Naso ◽  
Fernando A. Bellesi ◽  
Víctor M. Pizones Ruiz-Henestrosa ◽  
Ana M.R. Pilosof
Keyword(s):  
Bile Salt ◽  
Bile Salts ◽  
Binding Potential ◽  
Food Emulsifiers

In vitro absorption of bile salts by small intestine of rats and guinea pigs

1961 ◽  
Vol 200 (2) ◽  
pp. 313-317 ◽  
Author(s):  
Leon Lack ◽  
I. M. Weiner
Keyword(s):  
Small Intestine ◽  
Bile Acid ◽  
Active Transport ◽  
Sodium Azide ◽  
Concentration Gradient ◽  
Guinea Pigs ◽  
Bile Salts ◽  
Ileal Segment

The transport of taurocholic and glycocholic acids by the small intestine of rats and guinea pigs against a concentration gradient was studied by the everted gutsac technique. Transport of these substances is limited to the distal ileal segment. This transport is inhibited by anoxia, dinitrophenol and sodium azide. The system has a transport maximum. On the basis of these criteria bile acid reabsorption is considered to occur by active transport.

Hepatic bile flow

1984 ◽  
Vol 64 (4) ◽  
pp. 1055-1102 ◽  
Author(s):  
R. C. Strange
Keyword(s):  
Bile Salt ◽  
Bile Salts ◽  
Basolateral Membrane ◽  
Membrane Vesicles ◽  
Critical Micellar Concentration ◽  
Canalicular Membrane ◽  
Receptor Proteins ◽  
Subcellular Organelles ◽  
Golgi Bodies ◽  
Initial Event

The hepatocyte is a polar cell that can remove a variety of molecules from blood and excrete them into bile. This review is primarily concerned with the mechanism of transport of the principal anions--the bile salts--across the sinusoidal membrane, their passage through the cell, and excretion across the canalicular membrane. Clearly much of this process is poorly understood, but the study of the membrane stages should be facilitated by the ability to prepare purified sinusoidal and canalicular membrane vesicles. For example, the relative importance of albumin-binding sites as well as the putative bile salt receptor proteins can be better assessed. It seems likely that although the interaction of bile salts with receptor proteins is important, it is an initial event that puts the bile salt in the correct place for uptake to occur. The driving force for uptake is the Na+ gradient created across the basolateral membrane by the activity of the Na+-K+-ATPase. Within the cell, various modes of transport have been suggested. Several authors emphasize the importance of protein binding of bile salts, either because of their presumed ability to maintain the concentration of these anions in the hepatocyte below their critical micellar concentration or because of their putative role in transport. It is important to understand these aspects of the role of cytosolic proteins for several reasons. Knowledge of the true concentration of free bile salt within the cell should allow estimation of whether the electrochemical gradient is sufficient for bile salts to accumulate in bile without the need for active transport of molecules from the cell into the canaliculus. The compartmental model described by Strange et al. (153) offers one theoretical way of determining the concentration of free bile salt, although the problems inherent in studying amphipath binding to the membranes of subcellular organelles (31) require that the model be reevaluated by the hygroscopic-desorption method. The second role suggested for the cytosolic bile salt-binding proteins is as transport proteins. As discussed in section VI, I think it is unlikely that the proteins identified so far act in this way, and it is more likely that movement occurs by diffusion in free solution. It is also important to determine the possible involvement of subcellular organelles such as Golgi bodies. Little is known of their role in the transport of bile salts or indeed where bile salt micelles are formed.(ABSTRACT TRUNCATED AT 400 WORDS)

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