Lipase and Bile Salts in the Small Intestine of the Dog

Kiekens, R; Wissocq, P; Govaerts, J.

doi:10.1159/000197132

Cited by 5 publications

(3 citation statements)

References 8 publications

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“…At the peak excretory rate obtained, taurocholate is almost completely removed from the portal blood in its first passage through the liver (O'Maille et al 1967). The bile salt composition of portal venous blood probably reflects that of the intestine, in which most of the bile salt which has entered it remains in the conjugated form (Kiekens, Wissoig & Govaerts, 1971). The very much lower enterohepatic presentation rate of free bile acid which must therefore take place can only amount to a very small fraction of the maximum rate at which conjugation is capable of occurring (about 5-2 imole/min.…”

Section: Discussionmentioning

confidence: 99%

Possible explanations for the differences in secretory characteristics between conjugated and free bile acids.

O'Máille¹,

Richards²

1977

The Journal of Physiology

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SUMMARY1. The hepatic extraction fraction and maximum excretory rate of conjugated cholate are greater than those of free cholate (studied after acute taurine depletion); the possibility that this difference might be due to greater bile-to-blood back-diffusion of un-ionized cholic acid (pK. 5.5) compared to that of taurocholic acid (pK. 2) has been investigated by varying the pH of bile by secretin or acetazolamide administration i the anaesthetized dog.2. The mean biliary pH during free cholate excretion in the control state in twenty-three experiments was 7-5 (at which approximately 1I% of cholate is un-ionized). Three to fourfold changes in the hydrogen ion activity of bile (which resulted in changes of the same magnitude in the percentage of un-ionized cholic acid) had no significant effect on the total (mainly free) cholate maximum excretory rate. It is concluded that back-diffusion of un-ionized cholic acid in the bile ducts is not an important determinant of the secretary performance of free cholate.3. The bile flow rate associated with mainly free cholate excretion is much higher than that associated with taurocholate excretion at the same rate; the extra bile flow appears to arise largely by means that are independent of the osmotic effect of cholate excretion, as the osmotic coefficient (osmolality/total solute concentration) of bile containing mainly free cholate (calculated directly) was oniy slightly greater than that of bile containing mainly taurocholate (obtained by extrapolation) at the same total cholate concentration.4. The peak hepatic excretory rate of taurocholate following the instillation of the entire contents of the gall-bladder of a fasted dog into the distal ileum was only about one fifth of the maximum rate attainable; at the peak rate taurocholate is almost completely removed in the first passage of blood through the liver.

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Section: Discussionmentioning

confidence: 99%

Possible explanations for the differences in secretory characteristics between conjugated and free bile acids.

O'Máille¹,

Richards²

1977

The Journal of Physiology

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“…Endogenous bile salts, therefore, may prevent excessive desiccation of the luminal contents of the middle third of the small intestine by reducing net water transport there. The concentration of bile salts falls towards zero in the final quarter of the small intestine (Dietschy, 1967;Kiekens et al 1971). The active transport system for bile salts seems to allow rat ileum to conserve bile salts and the water and electrolytes delivered to it.…”

Section: Discussionmentioning

confidence: 99%

“…By the time chyme reaches the lower jejunum, however, most of its absorbable fat has been removed (Booth, Read & Jones, 1961;Borgstrdm, Dalhquist, Lundh & Sjdvall, 1957;Kiekens, Wissocq & Govaerts, 1971) and much of its lecithins have been digested and absorbed (Arnesjo, Nilsson, Barrowman & Borgstrdm, 1969). D .SU DR Because bile salts are not actively transported by the jejunal mucosa, their luminal concentration rises as water and nutrients are absorbed (Borg-str6m et al 1957;Dietschy, 1967;Kiekens et al 1971). For example, total bile salts are about 10 mm in proximal jejunum and about 20 mm in distal jejunum of fed rats (Dietschy, 1967).…”

Section: Discussionmentioning

confidence: 99%

Regional differences in the effect of bile salts on absorption by rat small intestine in vivo.

Saunders¹

1975

The Journal of Physiology

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SUMMARY1. The hypothesis that endogenous bile salts influence water absorption in rat small intestine was tested in vivo.2. Net water transport was measured under steady-state conditions during single-pass infusion of segments from three regions of the small intestine. Each segment served as its own control.3. Delipidated rat bile, and solutions of the principal bile salts of the rat, taurocholate and glycocholate, reduced absorption in the proximal jejunum but not in the distal ileum.4. 1-Palmitoyl,2-oleoyl lecithin, an important biliary lecithin, counteracted the inhibitory effect of taurocholate and of glycocholate on absorption. The presence of biliary lecithins probably explains why whole rat bile did not depress water absorption in the proximal jejunum.5. Net water transport in the distal jejunum was inversely related to log1o (taurocholate concentration).6. Endogenous bile salts may help to maintain the fluidity of the contents of the mid-small intestine in the rat after biliary and dietary lecithins have been absorbed.

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Effect of replacement therapy with cholylsarcosine on fat malabsorption associated with severe bile acid malabsorption

et al. 1992

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The efficacy of cholylsarcosine, a synthetic deconjugation-resistant and nonsecretory conjugated bile acid analog for the treatment of fat malabsorption caused by severe bile acid malabsorption, was assessed in an animal model. In two dogs, the ileum and ileocecal valve were resected, causing severe diarrhea, steatorrhea, bile acid malabsorption, and progressive weight loss. Cholylsarcosine was administered as the water-soluble sodium salt by mixing with the dog food. Various doses were explored as well as varying intakes of dog food. Fat absorption was assessed by gravimetric measurement of fecal fat; a nonabsorbable recovery marker (polyethylene glycol mol wt 4000) was used to correct for incomplete fecal collections. Cholylsarcosine caused a 5- to 30-fold increase in fat absorption but had no significant effect on weight loss or fecal weight. Duodenal content was collected during digestion of a meal via a surgically placed Thomas cannula; the aspirates were dilute, acidic, and had a low bile acid concentration. The bile acid concentration increased modestly when cholylsarcosine was administered, but remained below the critical micellization concentration. The results indicate that oral administration of cholylsarcosine improved dietary fat absorption in a canine model of severe bile acid malabsorption with associated steatorrhea and bile acid deficiency in the proximal small intestine. Studies with this compound in patients with nutritional problems because of steatorrhea and severe bile acid malabsorption appear warranted.

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Lipase and Bile Salts in the Small Intestine of the Dog

Cited by 5 publications

References 8 publications

Possible explanations for the differences in secretory characteristics between conjugated and free bile acids.

Possible explanations for the differences in secretory characteristics between conjugated and free bile acids.

Regional differences in the effect of bile salts on absorption by rat small intestine in vivo.

Effect of replacement therapy with cholylsarcosine on fat malabsorption associated with severe bile acid malabsorption

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