Quantitative Determination of Serum Bile Acids using a 7α-Hydroxysteroid Dehydrogenase

Fausa, O; Skålhegg, Bjørn A.

doi:10.3109/00365527709181685

Cited by 27 publications

(17 citation statements)

References 20 publications

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“…[15][16][17] The qualitative and quantitative composition of the bile, in terms of the individual BA, was determined by different combined chromatographic techniques. Bile sample underwent preliminary clean-up using conventional C-18 reverse-phase extraction (C-18 Bond Elut, Analytichem International, Harbor City, CA), which allows a complete recovery of all the studied BA as previously reported.…”

Section: Methodsmentioning

confidence: 99%

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Taurohyodeoxycholic acid protects against taurochenodeoxycholic acid-induced cholestasis in the rat

et al. 1998

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The prevention of the hepatotoxic effects produced by intravenous infusion of taurochenodeoxycholic acid (TCDCA) by coinfusion with taurohyodeoxycholic acid (THDCA) was evaluated in bile fistula rats; the hepatoprotective effects of the latter were also compared with those of tauroursodeoxycholic acid (TUDCA). Rats infused with TCDCA at a dose of 8 mol/min/kg showed reduced bile flow and calcium secretion, as well as increased biliary release of alkaline phosphatase (AP) and lactate dehydrogenase (LDH). This was associated with a very low biliary secretion rate of TCDCA (Ϸ1 mol/min/kg). Simultaneous infusion of THDCA or TUDCA at the same dose preserved bile flow and almost totally abolished the pathological leakage of the two enzymes into bile. The effect was slightly more potent for THDCA. The maximum secretion rate of TCDCA increased to the highest value (8 mol/min/kg) when coinfused with either of the two hepatoprotective bile acids (BA), which were efficiently and completely secreted in the bile, without metabolism. Calcium output was also restored and phospholipid (PL) secretion increased with respect to the control saline infusion. This increase was higher in the THDCA study. These data show that THDCA is highly effective in the prevention of hepatotoxicity induced by intravenous infusion of TCDCA by facilitating its biliary secretion and reducing its hepatic residence time; this was associated with selective stimulation of PL biliary secretion. (HEPATOLOGY 1998;27:520-525.)Taurohyodeoxycholic acid (THDCA) is the taurineamidated form of hyodeoxycholic acid, a natural bile acid present in the pig, other animal species, and also in humans. [1][2][3][4] The steroid structure is characterized by the presence of two hydroxy groups, 3␣ and 6␣, the latter of which is equatorial and oriented toward the back of the steroid moiety. As a result, this molecule is less detergent than the other dihydroxy bile acid (BA), such as chenodeoxycholic acid (CDCA) (3␣, 7␣) or its 3␣, 6␤ dihydroxy epimer. The hydrophobic-hydrophilic balance of THDCA resembles that of tauroursodeoxycholic acid (TUDCA), with which it also shares similar orientation of the 7␤ hydroxy group with respect to the 6␣ hydroxyl. The physicochemical properties of this molecule are quite similar to those of TUDCA in terms of lipophilicity and critical micellar concentration (CMC). 5,6 Because of its relatively high hydrophilicity, THDCA has been proposed for use as an alternative to ursodeoxycholic acid (UDCA) or TUDCA for the treatment of cholesterol gallstone dissolution. [7][8][9][10] Recent studies have reported its activity as a cholesterol-dissolving agent, both in vitro and in vivo, and this has been attributed to its ability to selectively stimulate biliary phospholipid secretion. 11 Moreover, hyodeoxycholic acid is a secondary BA derived from hyocholic acid by intestinal bacterial 7␣ dehydroxylation, and thus, it is quite stable to intestinal bacteria; this is a potential advantage compared with UDCA that can undergo either 7␤ dehydroxylation or 7␣...

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Section: Methodsmentioning

confidence: 99%

“…BA, PL, and calcium concentration were determined as previously reported, 15 AP and LDH activities were determined in bile by conventional enzymatic methods (Merck, Darmstadt, Germany).…”

Section: Biological Propertiesmentioning

confidence: 99%

Taurohyodeoxycholic acid protects against taurochenodeoxycholic acid-induced cholestasis in the rat

et al. 1998

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“…Fausa and Skalhegg (1977) reported that the PBA in healthy subjects averaged 73% of TBA. The reason for the difference in results between the authors is unknown, but it may be due to the difference in purity of 7a-HSD or in methodology.…”

Section: Discussionmentioning

confidence: 99%

“…Moreover, it has been reported that serum primary bile acids (PBA) are determined by an enzymatic fluorometric method using 7a-hydroxysteroid dehydrogenase (7a-HSD) (Macdonald 1976;Fausa and Skalhegg 1977). There are at present no detailed data available on values for the ratio of serum primary bile acids to total bile acids (P/T ratio) by an enzymatic fluorometric method in normal subjects and patients with liver disease.…”

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confidence: 99%

Measurement of the ratio of primary to total bile acids in serum by enzymatic fluorometric microassay and its clinical significance in patients with liver disease.

Ikawa¹,

Kawasaki

Yamanishi³

et al. 1985

Tohoku J. Exp. Med.

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An enzymatic fluorometric microassay using 3a-or 7a-hydroxysteroid dehydrogenase was devised to determine serum total or primary bile acids. The present microassay using 50 ul of a serum sample was run as a two-step method ; the first step is the reaction of substrates with NAD+ and the hydroxysteroid dehydrogenase to produce as much NADH as possible in the incubation system and the second step is that of NADH with resazurin coupled with 1-methoxy phenazinemethosulfate to produce fluorescent resorfin. The assay is specific for 3a-or 7a-hydroxy bile acids, sensitive (a detection limit of 1.5 ,u M with a linear range of 1.5-80 p M), reproducible (CV = less than 5%) and inexpensive. As measured by this microassay, the ratio of serum primary to total bile acids (P/T ratio)

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“…The final concentration of bilirubin in the infusates was 0.125 to 0.75 mmole/liter; although the solubility of bilirubin was clearly exceeded, concentrations are expressed as mM. The bilirubin contained greater than 99% IXa-isomer by thin-layer chromatography (23), and the infusate contained no bile salts as determined by a 3a-steroid dehydrogenase method sensitive to 1 nmole/ml (15).…”

Section: Perfusion Techniquementioning

confidence: 99%

The Effect of Bilirubin on the Function of Hamster Small Intestine

1981

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Summawintestinal secretion. rather than malabsomtion of dietarv carboJaundice phototherapy is associated with a significant incidence of watery diarrhea. We have postulated that acute intestinal secretion, rather than malabsorption of dietary carbohydrate, is an effect of a photoproduct of bilirubin upon the intestinal mucosa. Because a major effect of phototherapy is the hepatic excretion of nonconjugated bilirubin, we investigated the effect of bilirubin on small intestinal function in the hamster in vivo.The entire small intestine was luminally perfused in vivo with solutions containing bilirubin (0.125 to 0.75 mmole/liter) and net water and sodium fluxes were measured. Control animals absorbed both water (J, ": ? = 58.9 pl/min/g) and sodium (JEZt SpeculationThese data seem consistent with the hypothesis that jaundice phototherapy causes watery diarrhea by enhancing the hepatic excretion of nonconjugated bilirubin, which, in turn, causes intestinal secretion.A recent survey has estimated that 10% of infants born in the United States receive phototherapy for neonatal jaundice (16). Such therapy is associated with a significant (9.5%) incidence of watery diarrhea (19), characterized by increased fecal water loss (26) and decreased gut transit time (29). The pathogenesis of this diarrhea has not been established, but a photoproduct of bilirubin is presumed to be involved in the mechanism because both light and hyperbilirubinemia are required for its development (29). Although intestinal lactase deficiency has been found in affected infants (I), recent data indicate that lactose intolerance cannot be demonstrated in these infants (13,14). We have observed diarrhea to develop within a few hours of light exposure and in the absence of oral intake. These observations lead us to postulate that acute hydrate, is an effect of a photoproduct of bilirubin.Phototherapy induces hepatic excretion of nonconjugated bilirubin through a postulated mechanism involving configurational isomerization of bilirubin, Z-Z bilirubin IXa, to "photobilirubin," composed of the two Z-E and the E-E bilirubin IXa configurational isomers, a pigment which is readily excreted by the liver. The kinetics of reversion of photobilirubin to bilirubin have not been elucidated, but the Z-E isomers are presumably unstable and revert to Z-Z bilirubin within the biliary tract or the gut (6,20,24,27). Overall, a major effect of phototherapy is the hepatic excretion of nonconjugated bilirubin into the gut.We have tested the possibility that bilirubin causes intestinal secretion by measuring the effects of bilirubin on the small intestinal function of hamsters. The results indicate that bilirubin itself can induce intestinal secretion and suggest that the watery diarrhea often witnessed in jaundiced infants treated by phototherapy may be a consequence of the high concentrations of bilirubin within the intestinal lumen. MATERIALS AND METHODS PERFUSION TECHNIQUEFed, male Syrian golden hamsters (Sprague-Dawley, Madison, WI) weighing between 80 and 110 g were a...

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Quantitative Determination of Serum Bile Acids using a 7α-Hydroxysteroid Dehydrogenase

Cited by 27 publications

References 20 publications

Taurohyodeoxycholic acid protects against taurochenodeoxycholic acid-induced cholestasis in the rat

Taurohyodeoxycholic acid protects against taurochenodeoxycholic acid-induced cholestasis in the rat

Measurement of the ratio of primary to total bile acids in serum by enzymatic fluorometric microassay and its clinical significance in patients with liver disease.

The Effect of Bilirubin on the Function of Hamster Small Intestine

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