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George JW, Nulk K, Weiss A, Bruss ML, Cornelius CE. Biliverdin reductase activity in cattle, sheep, rabbits and rats. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1989; 21:477-81. [PMID: 2759328 DOI: 10.1016/0020-711x(89)90127-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
1. Biliverdin reductase (BVR) activity was measured in post-microsomal supernatants of livers of cattle, sheep, rabbits and rats. BVR activities in bovine and ovine livers were 4.7 and 5.0%, respectively, of rat liver activity. 2. The finding of BVR activity in ruminants is in contrast to a previous report and may be due to the use of a different assay system. 3. Lapine liver had the lowest BVR activity of only 0.37% of rat liver activity. 4. Increasing the available heme by phenylhydrazine administration did not induce increased hepatic or splenic BVR activity in rabbits. 5. Maximal BVR activities were attained using NADPH as cofactor at pH 8.7 in sheep and rabbits and at pH 8.4 in cattle. 6. Differing concentrations of bovine or human albumins enhanced or inhibited BVR activity quite differently in the various species. 7. The finding of a very low, but measurable BVR activity in lapine liver and spleen may explain, in part, why rabbits, unlike rats, cattle and sheep, excrete primarily biliverdin (70%) into bile.
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Affiliation(s)
- J W George
- California Primate Research Center, University of California, Davis
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52
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Biochemical Disorders in Nonhuman Primates with Hyperbilirubinemias. Clin Chem 1989. [DOI: 10.1007/978-1-4613-0753-2_79] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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53
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Hauser SC, Ziurys JC, Gollan JL. A membrane transporter mediates access of uridine 5'-diphosphoglucuronic acid from the cytosol into the endoplasmic reticulum of rat hepatocytes: implications for glucuronidation reactions. BIOCHIMICA ET BIOPHYSICA ACTA 1988; 967:149-57. [PMID: 3142526 DOI: 10.1016/0304-4165(88)90004-9] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Hepatic glucuronidation of a wide variety of substrates is catalyzed by the membrane-bound UDP-glucuronosyltransferases. Uridine 5'-diphosphoglucuronic acid (UDP-GlcUA) is the essential cosubstrate for all UDP-glucuronosyltransferase-mediated reactions. The mechanism by which this bulky, hydrophilic nucleotide-sugar is transported from the cytosol (where it is synthesized) to its binding site(s) on the enzyme is unknown. To determine whether a membrane carrier mediates the access of UDP-GlcUA into the endoplasmic reticulum, the transport of uridine 5'-diphospho-D-[U-14C]glucuronic acid into vesicles of rough and smooth endoplasmic reticulum isolated from rat liver was investigated at 38 degrees C using a rapid filtration technique. Uptake of UDP-GlcUA by both rough and smooth vesicles was extremely rapid (linear for only 10-20 s) and temperature-dependent (negligible at 4 degrees C). UDP-GlcUA uptake was saturable, and similar kinetic parameters were obtained for rough and smooth vesicles (Km 1.9 microM, Vmax 443 pmol/mg protein per min, and Km 1.3 microM, Vmax 503 pmol/mg protein per min, respectively). The uptake of UDP-GlcUA also exhibited a high degree of specificity, since many related compounds, including UMP, UDP and UDP-Glc, did not influence uptake. In addition, the non-penetrating inhibitors of anion transport, 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid (SITS), 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS), and probenecid, markedly inhibited UDP-GlcUA uptake. Finally, osmotic modulation of the intravesicular volume did not affect total uptake of UDP-GlcUA by membrane vesicles at equilibrium, indicating that this nucleotide-sugar is transported into the membrane rather than the intravesicular space. Collectively, these data provide direct evidence for a specific, carrier-mediated uptake process, which transports UDP-GlcUA from the cytosol into the endoplasmic reticulum of hepatocytes. This UDP-GlcUA transporter may be involved in the regulation of hepatic glucuronidation reactions.
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Affiliation(s)
- S C Hauser
- Department of Medicine, Harvard Medical School, Boston, MA
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54
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Rothuizen J, Heirwegh KP, van Kouwen AM. Novel method for high-performance liquid chromatography of azo derivatives of conjugated and unconjugated bilirubin. JOURNAL OF CHROMATOGRAPHY 1988; 427:19-28. [PMID: 3410902 DOI: 10.1016/0378-4347(88)80101-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A method for the separation and quantitation of ethyl anthranilate or p-iodoaniline azo derivatives of bile pigments was developed using reversed-phase high-performance liquid chromatography. A convenient separation was achieved in 15 min, permitting the quantitation of the unconjugated azo-dipyrrole (alpha o) and its glucuronide (delta), xyloside (alpha 2) and glucoside (alpha 3) conjugates. The pathological beta- and gamma-azo pigments, derived from bilirubin glucuronide isomers that occur in cholestatic bile or plasma, are also detected in this system. The results of this method as applied to bile from 25 healthy dogs were in excellent agreement with the values obtained by reversed-phase chromatography of bilirubin and its mono- and dimethyl esters produced from the corresponding conjugates by alkaline methanolysis. This system permits the sensitive and convenient determination of bilirubin and its conjugation pattern in biological fluids.
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Affiliation(s)
- J Rothuizen
- Small Animal Clinic, University of Utrecht, The Netherlands
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55
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Mottino AD, Pellegrino JM, Guibert EE, Roma MG, Rodríguez Garay EA. Comparison of hepatic, renal and intestinal bilirubin UDP-glucuronyl transferase activities in rat microsomes. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1988; 20:1113-6. [PMID: 3150356 DOI: 10.1016/0020-711x(88)90256-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
1. Bilirubin UDP-glucuronyltransferase activity and its dependence on substrate concentrations in rat liver, renal cortex and intestinal mucosa microsomes were studied. 2. Bilirubin monoglucuronide synthesis from unconjugated bilirubin was a higher capacity, lower affinity step in comparison with bilirubin diglucuronide formation in the three tissues tested. 3. Bilirubin glucuronide formation in liver microsomes showed a higher capacity but a lower affinity than extrahepatic ones. Renal cortex and intestinal mucosa exhibited similar kinetics parameters. 4. In vitro bilirubin glucuronidation in renal cortex and intestinal mucosa was quantitatively important as compared with the hepatic one.
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Affiliation(s)
- A D Mottino
- Instituto de Fisiología Experimental, Universidad Nacional de Rosario, Argentina
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56
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Sommerer U, Gordon ER, Goresky CA. Microsomal specificity underlying the differing hepatic formation of bilirubin glucuronide and glucose conjugates by rat and dog. Hepatology 1988; 8:116-24. [PMID: 3338698 DOI: 10.1002/hep.1840080123] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Bilirubin monoglucuronide monoglucoside diester is one of the principal bilirubin conjugates in dog bile (and a lesser conjugate, in human bile), and bilirubin diglucoside is an occasional trace conjugate in dog bile whereas, in contrast, neither is detectable in rat bile. In order to investigate, in comparative fashion, the factors underlying the formation of glucuronide and glucose-containing conjugates, hepatic microsomes were isolated by differential centrifugation from the livers of both normal mongrel dogs and Sprague-Dawley rats, and their formation of bilirubin conjugates examined, in the presence of varying levels of UDP-glucuronate and UDP-glucose. Bilirubin and its conjugates were extracted and separated by high-performance liquid chromatography; a new methodology was devised, which clearly separates bilirubin diglucoside from bilirubin monoglucuronide, as well as bilirubin diglucuronide, the mixed monoglucuronide monoglucoside conjugate and bilirubin monoglucoside. At bilirubin levels of 12.5 microM, in the presence of equal amounts of both UDP-glucuronate and UDP-glucose, dog microsomes formed substantial amounts of both bilirubin diglucuronide and the mixed monoglucuronide-monoglucoside conjugate, and minor amounts of bilirubin monoglucuronide and bilirubin diglucoside. Microsomes from rat liver, under similar conditions, formed only bilirubin diglucuronide and bilirubin monoglucuronide. When only UDP-glucose was present, dog microsomes formed predominantly diglucoside and rat, predominantly monoglucoside. The findings imply that it is not the availability of the UDP-glycoside but rather the preference of the microsomal enzymic system for the different glycosidic nucleotides which dictates the varieties of bilirubin conjugates ordinarily formed in these two species.
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Affiliation(s)
- U Sommerer
- McGill University Medical Clinic, Montreal General Hospital, Quebec, Canada
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57
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Stocker R, Ames BN. Potential role of conjugated bilirubin and copper in the metabolism of lipid peroxides in bile. Proc Natl Acad Sci U S A 1987; 84:8130-4. [PMID: 3479781 PMCID: PMC299492 DOI: 10.1073/pnas.84.22.8130] [Citation(s) in RCA: 108] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Conjugated bilirubin and copper ions at their physiological concentrations in bile may play an important role in hydroperoxide and other detoxification. Conjugated bilirubin may also be an important chain-breaking antioxidant preventing lipid peroxidation. Bilirubin ditaurine (BR-DT), a water-soluble model compound of conjugated bilirubin, completely prevents the peroxyl radical-induced oxidation of phosphatidylcholine in either multilamellar liposomes or micelles. This antioxidant activity is associated with the bilirubin moiety of BR-DT, since taurine alone is inefficient in scavenging peroxyl radicals. The number of peroxyl radicals trapped per molecule of BR-DT is 1.9, compared to 4.7 trapped per molecule of biliverdin, the water-soluble physiological precursor of bilirubin. Peroxyl radical-induced oxidation of BR-DT results in a spectral shift in maximal absorbance toward shorter wavelengths; biliverdin is not formed as a major oxidation product. BR-DT, but neither taurine nor biliverdin, greatly accelerates the cupric ion-catalyzed decomposition of linoleic acid hydroperoxide. In the presence of ferric ion, BR-DT shows no lipid hydroperoxide-degrading activity. Addition of cupric ion to BR-DT results in formation of a complex with spectral features similar to that of a biliverdin-cupric ion complex, indicating that BR-DT and cupric ion undergo redox reactions.
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Affiliation(s)
- R Stocker
- Department of Biochemistry, University of California, Berkeley 94720
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58
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Abstract
Human hepatoma which had been xenografted into nude mice have been estimated for their ability to catalyze glucuronic acid and glucose conjugation of endogenous compounds and p-nitrophenol. The xenobiotic p-nitrophenol was glucuronidated with a comparable rate in microsomes from human hepatoma, human liver and host liver. With regard to glucuronic acid or glucose conjugation of the endogenous compounds of bile acids, bilirubin and steroid hormones, glucosidation of bile acids was the only conjugation mechanism that was not decreased or deficient in microsomes from hepatoma, but showed about a 2-fold increase in reaction rate compared to normal human liver. Human hepatoma and host liver were shown to respond to phenobarbital treatment which led to about a 2-fold increase in UDP-glucuronosyltransferase activity toward bilirubin in hepatoma and in host liver. Compared to normal tissues, alterations in the pattern of glycoside conjugating enzymes were not only observed in microsomes from human hepatoma, but also in microsomes from human adenocarcinoma of the kidney, exhibiting negligible UDP-glucuronosyltransferase activities toward bile acids and steroid hormones. Bile acid glucoside formation was measurable in kidney adenocarcinoma with an activity which was similar to the activity observed in hepatoma. In comparison to normal renal tissue, glucose-conjugating activity toward bile acids decreased about 2-fold in kidney adenocarcinoma.
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Affiliation(s)
- H Matern
- Department of Internal Medicine, Medical Faculty of Aachen University of Technology, Germany
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59
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Abstract
The kinetics of unconjugated 3H-bilirubin are described in 25 healthy dogs and 35 dogs with spontaneous hepatobiliary or haemolytic disease, using a two-compartment model. The bilirubin production rates from erythrocyte degradation (PE), ineffective erythropoiesis (PI) and catabolism of hepatic haemoproteins (PL), were derived from the incorporation of 14C-glycine into haemoglobin and stercobilin. These combined measurements permitted an integral survey of bilirubin metabolism in health and disease. The concentration of unconjugated bilirubin in plasma and its fraction of total bilirubin levels were similar in hepatic and haemolytic disorders. This was explained by the highly increased bilirubin production rates in both types of disease. In addition, the hepatic bilirubin clearance was severely impaired in fulminant hepatitis and in cirrhosis, and moderately decreased in the other hepatobiliary diseases and in primary haemolysis. The erythrocyte lifespan was reduced in all animals but one. In addition to haemolysis, the contribution of PI and PL was variable, and in two dogs PL was the principle source of highly increased bilirubin production rates. These data indicate that the concentration of unconjugated bilirubin in plasma or its fraction of total pigments is unreliable in the discrimination of canine hepatobiliary disease from haemolytic disorders.
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Affiliation(s)
- J Rothuizen
- Small Animal Clinic, State University of Utrecht, The Netherlands
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60
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Vanstapel F, Blanckaert N. Endogenous esterification of bilirubin by liver microsomes. Evidence for an intramicrosomal pool of UDP-glucose and lumenal orientation of bilirubin UDP-glycosyltransferase. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(18)61238-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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61
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Spivak W, DiVenuto D, Yuey W. Non-enzymic hydrolysis of bilirubin mono- and diglucuronide to unconjugated bilirubin in model and native bile systems. Potential role in the formation of gallstones. Biochem J 1987; 242:323-9. [PMID: 3593251 PMCID: PMC1147708 DOI: 10.1042/bj2420323] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Pigment gallstones contain considerable amounts of unconjugated bilirubin (UCB) in the form of calcium bilirubinate and/or bilirubin polymers. Since more than 98% of bile pigments are excreted as conjugates of bilirubin, the source of this UCB needs to be identified. By using a rapid h.p.l.c. method, we compared the non-enzymic hydrolysis of bilirubin monoglucuronide (BMG) and bilirubin diglucuronide (BDG) to UCB in model bile and in native guinea-pig bile. Model biles containing 50 microM solutions of pure BMG and BDG were individually incubated in 25 mM-sodium taurocholate (NaTC) and 0.4 M-imidazole/5 mM-ascorbate buffer (TC-BUF) at 37 degrees C. Over an 8 h period, BMG hydrolysis produced 4-6 times more UCB than BDG hydrolysis. At pH 7.4, 25% of the BMG was converted into UCB, whereas only 4.5% of BDG was converted into UCB. Hydrolysis rates for both BMG and BDG followed the pH order 7.8 greater than 7.6 approximately equal to 7.4 greater than 7.1 Incubation with Ca2+ (6.2 mM) at pH 7.4 in TC-BUF resulted in precipitated bile pigment which, at 100 X magnification, appeared similar to precipitates seen in the bile of patients with pigment gallstones. At pH 7.4, lecithin (crude phosphatidylcholine) (4.2 mM) was a potent inhibitor of hydrolysis of BMG and BDG. The addition of a concentration of cholesterol equimolar with that of lecithin eliminated this inhibitory effect. Guinea-pig gallbladder bile incubated with glucaro-1,4-lactone (an inhibitor of beta-glucuronidase) underwent hydrolysis similar to the model bile systems. The non-enzymic hydrolysis of bile pigments, especially BMG, may be an important mechanism of bile-pigment precipitation and, ultimately, of gallstone formation.
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62
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Muñoz ME, González J, Esteller A. Effect of glucose administration on bilirubin excretion in the rabbit. EXPERIENTIA 1987; 43:166-8. [PMID: 2949996 DOI: 10.1007/bf01942836] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The effect of i.v. infusion of glucose on the hepatic handling of bilirubin was examined in rabbits. A significant increase in the excretion of conjugated bilirubin into the bile was observed, accompanied by a decrease in bilirubinemia. Hepatic bilirubin concentrations were lowered and the UDP-glucose concentrations and liver UDP-glucuronosyl and UDP-glucosyl transferase activities increased.
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63
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Smith DJ, Gordon ER. Role of the physical state of the hepatic microsomal membrane in the formation of bilirubin diglucuronide. J Hepatol 1987; 4:1-7. [PMID: 3571927 DOI: 10.1016/s0168-8278(87)80002-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
In vitro formation of bilirubin diglucuronide by rat hepatic microsomes proceeds efficiently only under specific conditions; i.e., a low level of bilirubin, temperature greater than 23-24 degrees C and treatment of the microsomes with a very specific level of perturbant (J. Biol. Chem., 258: 15028-15036). In the present study, the effect of temperature and detergents on the anisotropy of fluorescent probes in the rat hepatic microsomal membrane was used to determine the role of the physical state of the membrane in controlling the formation of bilirubin diglucuronide. A lipid phase separation that occurred at 23 +/- 2 degrees C was identified in these membranes indicating that bilirubin diglucuronide is formed efficiently only above the lipid phase separation when the phospholipids are in the liquid crystalline state. In addition, use of fluorescent probes for the surface and core of the membrane indicates that alterations in the physical state of the hydrophobic core rather than the phospholipid polar head group region of the membrane controls the in vitro formation of bilirubin diglucuronide.
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64
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Muraca M, Fevery J, Blanckaert N. Relationships between serum bilirubins and production and conjugation of bilirubin. Studies in Gilbert's syndrome, Crigler-Najjar disease, hemolytic disorders, and rat models. Gastroenterology 1987; 92:309-17. [PMID: 3792767 DOI: 10.1016/0016-5085(87)90123-5] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The pattern of serum bilirubins was determined in serum of humans and rats with unconjugated hyperbilirubinemia due to increased pigment load or defective hepatic conjugation. Bilirubin ester conjugates were present in all serum samples tested and were identified as bilirubin 1-O-acyl glucuronides. In Gilbert's syndrome, the concentration of total conjugates was comparable to the values in healthy control subjects. Because the concentration of unconjugated pigment was increased, the fraction of conjugated relative to total bilirubins was markedly decreased. Sera from patients with Crigler-Najjar disease differed from those with Gilbert's syndrome by the higher unconjugated bilirubin levels and the undetectability of diconjugated bilirubins. A striking finding was that in hemolytic disease, the concentration of both monoconjugates and diconjugates was enhanced in parallel with the increase of unconjugated pigment. Therefore, the fraction of conjugated relative to total bilirubins remained within the normal range. As in Gilbert's syndrome, heterozygote R/APfd-j/+ rats with impaired hepatic bilirubin conjugation exhibit an increased unconjugated bilirubin level in serum, whereas the concentration of total conjugates was comparable to the values in normal rats. In serum of normal rats loaded intraperitoneally with unconjugated bilirubin, both unconjugated and mono- and diconjugated bilirubins were increased in parallel so that the ratio of unconjugated to esterified pigment remained unaffected. Decreased hepatic conjugation or increased bilirubin load was associated with a lower percentage of diconjugates relative to total conjugates both in human and rat serum. The present results are consistent with a compartmental model in which there is bidirectional transfer across the sinusoidal membrane for unconjugated bilirubin as well as for the bilirubin glucuronides. Because typical patterns of serum bilirubins are found in Gilbert's syndrome and patients with hemolytic hyperbilirubinemia, determination of esterified bilirubins in serum is of value to study the pathophysiology and the differential diagnosis of unconjugated hyperbilirubinemia.
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65
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Coughtrie MW, Burchell B, Bend JR. Purification and properties of rat kidney UDP-glucuronosyltransferase. Biochem Pharmacol 1987; 36:245-51. [PMID: 3101703 DOI: 10.1016/0006-2952(87)90696-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Rat kidney microsomes catalysed the glucuronidation of 1-naphthol, 4-nitrophenol, bilirubin and beta-estradiol. Unlike rat hepatic microsomes, UDP-glucuronosyltransferase activity towards morphine and testosterone was not detectable. Treatment of rats with beta-naphthoflavone resulted in a 3-fold induction of renal UDPGT activity towards 1-naphthol, 4-nitrophenol and phenol, and a 2-fold induction of bilirubin and beta-estradiol glucuronidation. No induction of renal UDPGT was observed after phenobarbital treatment, but renal bilirubin UDPGT activity was specifically induced after treatment of rats with clofibrate. UDPGT activity was purified from rat kidney by a combination of ion-exchange chromatography, gel filtration and affinity chromatography on UDP-hexanolamine Sepharose. One major protein-staining polypeptide was observed on silver-stained SDS-polyacrylamide gels, of molecular weight 55,000 Da, and a minor band of 54,000 Da was also present. Indeed, immunoblot analysis of purified renal UDPGTs with anti-rat liver UDPGT antibodies revealed two immuno-reactive polypeptides of molecular weight 55,000 and 54,000 Da. The highly purified preparations catalysed the glucuronidation of 1-naphthol and bilirubin. Glucuronidation of bilirubin by purified renal UDPGT preparations required the presence of phospholipid, the activity being further enhanced by incubation with rat lung microsomes. The data presented indicate that two UDPGT isoenzymes have been copurified.
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66
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Fevery J, Muraca M, Mesa V, Van Steenbergen W, Blanckaert N. Plasma bilirubin pigments in health and disease. Mol Aspects Med 1987; 9:391-404. [PMID: 3306238 DOI: 10.1016/0098-2997(87)90005-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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67
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Grossbard ML, Boyer JL, Gordon ER. The excretion pattern of biliverdin and bilirubin in bile of the small skate (Raja erinacea). J Comp Physiol B 1987; 157:61-6. [PMID: 3571566 DOI: 10.1007/bf00702729] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Bile pigment composition (biliverdin, bilirubin and their conjugates) was analyzed in stored gallbladder bile and newly synthesized hepatic bile from the small skate (Raja erinacea). During a five day period of captivity, gallbladder volume remained relatively constant while bilirubin and biliverdin content increased two to three fold. Biliverdin which accounted for 50% of the pigments did not increase as a percentage of tetrapyrroles during this period. The relative proportion of bilirubin and its conjugates also remained constant, averaging 65% for bilirubin monoglucuronide, 30% for bilirubin diglucuronide and 5% for unconjugated bilirubin as measured by HPLC methods. Intravenous administration of biliverdin resulted in significant increases in the biliary excretion of both biliverdin and all bilirubin tetrapyrroles. Insignificant quantities of 3H-biliverdin were detected in hepatic bile following the intravenous administration of 3H-bilirubin. These studies indicate that the small skate excreted both biliverdin and bilirubin conjugates in bile and that the biliverdin was not produced by in vitro oxidation of bilirubin or its metabolites.
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68
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Burchell B, Coughtrie MW, Jackson MR, Shepherd SR, Harding D, Hume R. Genetic deficiency of bilirubin glucuronidation in rats and humans. Mol Aspects Med 1987; 9:429-55. [PMID: 3306240 DOI: 10.1016/0098-2997(87)90007-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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69
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Hauser SC, Ziurys JC, Gollan JL. Regulation of bilirubin glucuronide synthesis in primate (Macaca fascicularis) liver. Kinetic analysis of microsomal bilirubin uridine diphosphate glucuronyltransferase. Gastroenterology 1986; 91:287-96. [PMID: 3087808 DOI: 10.1016/0016-5085(86)90559-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Hepatic bilirubin uridine diphosphate glucuronyl-transferase (UDP-glucuronyltransferase) catalyzes the formation of bilirubin monoglucuronides (BMG, C-8 and C-12 isomers) and bilirubin diglucuronide (BDG) from bilirubin and the cosubstrate, UDP-glucuronic acid. Distinctive patterns of bile pigment excretion occur in different species and in pathologic disorders (e.g., Gilbert's syndrome). In normal human and monkey (Macaca fascicularis) bile, the proportion of BDG exceeds that of BMG and the C-8/C-12 BMG isomer ratio approaches unity. To investigate the mechanisms responsible for the patterns of BDG and BMG isomers in bile, we used a radiochemical assay to analyze the kinetics and regulation of bilirubin UDP-glucuronyltransferase in microsomes prepared from monkey liver. The synthesis of BMG from bilirubin was a higher capacity, lower affinity step (Vmax = 295 pmol/mg protein X min, Km = 24 microM) than BDG synthesis from endogenously formed BMG (Vmax = 170 pmol/mg protein X min, Km = 14 microM). This observation was confirmed when biosynthetically prepared BMG was used as substrate. The rate of formation of BDG relative to BMG was modulated by both bilirubin and UDP-glucuronic acid concentration, whereas the C-8/C-12 BMG isomer ratio was influenced exclusively by UDP-glucuronic acid concentration. The data obtained with increasing UDP-glucuronic acid concentration did not obey conventional single-site kinetics, suggesting the presence of more than one binding site on the enzyme or a membrane transporter for this nucleotide sugar. These findings demonstrate that microsomal bilirubin UDP-glucuronyltransferase has a greater capacity for BMG than BDG synthesis, and thus support the concept that the decreased BDG/BMG ratio in the bile of patients with reduced hepatic enzyme activity (i.e., Gilbert's syndrome and type II Crigler-Najjar disease) reflects the diminished capacity of the enzyme to synthesize BDG from BMG. Bilirubin and UDP-glucuronic acid concentrations both appear to be pivotal in regulating the synthesis of individual bilirubin glucuronides and hence the patterns of bilirubin conjugates excreted in bile.
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70
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Yamashita M, Adachi Y, Yamamoto T. Analysis of bilirubin conjugates in human bile by column liquid chromatography. JOURNAL OF CHROMATOGRAPHY 1986; 375:386-91. [PMID: 3700563 DOI: 10.1016/s0378-4347(00)83732-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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71
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Sieg A, Vaclavsky J, Stiehl A, Raedsch R, Czygan P, Kommerell B. Isomers of bilirubin glucuronide in serum and bile before and after relief of common duct obstruction. J Hepatol 1986; 3:341-7. [PMID: 3559144 DOI: 10.1016/s0168-8278(86)80487-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Isomers of bilirubin glucuronide with the bilirubin acyl group attached to the C1-, C2-, C3- and C4-positions of the glucuronyl residue are present in bile of patients with extrahepatic cholestasis, whereas in normal bile only C1-isomers are found. In the present study, these bilirubin glucuronide isomers, and the fractions of unconjugated bilirubin, and bilirubin mono- and diconjugates were determined in serum and bile of 8 patients before and after relief of common duct obstruction by endoscopic papillotomy. Before papillotomy we found 39.6% C1-isomers (median value), 22.2% C2-isomers, 19.3% C3-isomers and 11.4% C4-isomers in the bile. The values in serum before papillotomy were comparable. Twenty-four hours after papillotomy, the level of C1-isomers in bile increased significantly to 56.3% (P less than 0.05) with a concomitant decrease of the non-C1-isomers. In contrast, in serum the isomers of bilirubin glucuronide did not change significantly at 24 h after papillotomy. Before papillotomy, the fraction of unconjugated bilirubin in bile was 3.6% of the total, with 15.8% bilirubin monoconjugates and 75.5% bilirubin disconjugates. After papillotomy, unconjugated bilirubin decreased to 1.6% (n.s.) and bilirubin monoconjugates to 11.9% (n.s.), while bilirubin diconjugates increased to 86.1% (P less than 0.05). In serum, the elevated fractions of bilirubin diconjugates and monoconjugates decreased from 38.4 to 32.2% (P less than 0.05) and from 29.6 to 23.4% (n.s.), respectively. In parallel, the fraction of unconjugated bilirubin in serum increased from 24.1 to 37.0% (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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72
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Muñoz ME, González J, Esteller A. Bile pigment formation and excretion in the rabbit. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. A, COMPARATIVE PHYSIOLOGY 1986; 85:67-71. [PMID: 2876822 DOI: 10.1016/0300-9629(86)90463-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Bile and plasma levels of biliverdin and bilirubin, together with the hepatic biliverdin reductase and bilirubin UDP-glucuronosyl transferase activities, were studied in the rabbit. No biliverdin could be detected in the blood plasma. The bilirubin concentration in blood was 7.81 +/- 0.79 mumol/l. Biliverdin was the predominant pigment in bile (63%). Hepatic biliverdin reductase activity was 0.086 +/- 0.016 nmol/mg protein/hr. The synthesis of bilirubin was apparently limited by the enzyme activity. Most of the bilirubin in bile was conjugated (90%) with monoconjugates predominating (75%). Hepatic UDP-glucuronosyl transferase activity was 2.65 +/- 0.18 and 1.14 +/- 0.16 mumol/mg protein/hr with and without activation, respectively.
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73
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Adachi S, Uesugi T, Kamisaka K. Study of bilirubin metabolism by high-performance liquid chromatography: stability of bilirubin glucuronides. Arch Biochem Biophys 1985; 241:486-93. [PMID: 4037800 DOI: 10.1016/0003-9861(85)90574-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The stabilities of bilirubin (BR) glucuronide, monoglucuronide (BMG), and diglucuronide (BDG) were studied under various conditions by HPLC. In aqueous media, BMG showed a pronounced lability and was easily transformed into equimolar BDG and BR. It was proved by direct analysis of tetrapyrrole isomers that BDG and BR were formed from dipyrrole exchange of BMG molecules. All reducing agents examined (sodium ascorbate, cysteine, GSH, dithiothreitol, NADH, and NADPH) suppressed the transformation of BMG into BDG and BR. Bovine serum albumin and rat liver cytosol fractions also stabilized BMG strongly. BDG was fairly stable in aqueous media as compared with BMG. When BMG was incubated both with and without liver plasma membranes (N2 fraction) from Wistar rats, the formation rates of BDG and BR in both incubation mixtures were exactly the same. The composition of BDG and BR isomers was the same in both mixtures. Also, heat denaturation of the plasma membranes did not affect formation rates. Moreover, the reaction was completely inhibited by sodium ascorbate. These findings indicate that rat liver plasma membranes have no enzyme activity for BDG formation from BMG.
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74
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Gourley GR, Mogilevsky W, Arend RA, Siegel FL, Odell GB. Effects of anesthetic agents on bile pigment excretion in the rat. Hepatology 1985; 5:610-4. [PMID: 4018732 DOI: 10.1002/hep.1840050415] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Anesthesia-induced alterations in bilirubin conjugation were studied. Rats were fitted with bile duct and jugular vein catheters while anesthetized with diethyl ether, ketamine or pentobarbital. As anesthesia abated, bile was collected for the next 5 hr and analyzed for flow rate, total bilirubin excretion and bilirubin glucuronide composition. The high-performance liquid chromatography method used allowed direct analysis of bile without derivatization or extraction. Ether anesthesia was associated with a reversible suppression of diglucuronide formation and total bilirubin excretion, with reciprocal monoglucuronide changes. Bile flow and pigment excretion were variable with ketamine. Pentobarbital provided the most uniform excretion data, although the ratio of C-8:C-12 monoglucuronide varied with all drugs. These data are consistent with recently reported drug-induced alterations in hepatic uridine diphosphoglucuronic acid concentration and support the hypothesis that alterations in this substrate concentration are capable of influencing rates of hepatic glucuronide formation.
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75
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Kurtin WE, Schwesinger WH. Assay of beta-glucuronidase in bile following ion-pair extraction of pigments and bile acids. Anal Biochem 1985; 147:511-6. [PMID: 4014691 DOI: 10.1016/0003-2697(85)90306-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A method for improving the assay of beta-glucuronidase in hepatic and gallbladder bile is described. The method uses ion-pair extraction with N,N,N-triheptyl-1-heptanaminium bromide to remove pigments and bile acids. Conjugated bilirubin, unconjugated bilirubin, and taurine and glycine conjugates of deoxycholic and chenodeoxycholic acids are extracted efficiently from bile by the procedure. The sensitivity of the spectrophotometric assay of beta-glucuronidase in bile using phenolphthalein glucuronide is increased significantly.
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76
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Spivak W, Carey MC. Reverse-phase h.p.l.c. separation, quantification and preparation of bilirubin and its conjugates from native bile. Quantitative analysis of the intact tetrapyrroles based on h.p.l.c. of their ethyl anthranilate azo derivatives. Biochem J 1985; 225:787-805. [PMID: 3919713 PMCID: PMC1144656 DOI: 10.1042/bj2250787] [Citation(s) in RCA: 120] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We describe a facile and sensitive reverse-phase h.p.l.c. method for analytical separation of biliary bile pigments and direct quantification of unconjugated bilirubin (UCB) and its monoglucuronide (BMG) and diglucuronide (BDG) conjugates in bile. The method can be 'scaled up' for preparative isolation of pure BDG and BMG from pigment-enriched biles. We employed an Altex ultrasphere ODS column in the preparative steps and a Waters mu-Bondapak C18 column in the separatory and analytical procedures. Bile pigments were eluted with ammonium acetate buffer, pH 4.5, and a 20 min linear gradient of 60-100% (v/v) methanol at a flow rate of 2.0 ml/min for the preparative separations and 1.0 ml/min for the analytical separations. Bile pigments were eluted in order of decreasing polarity (glucuronide greater than glucose greater than xylose conjugates greater than UCB) and were chemically identified by t.l.c. of their respective ethyl anthranilate azo derivatives. Quantification of UCB was carried out by using a standard curve relating a range of h.p.l.c. integrated peak areas to concentrations of pure crystalline UCB. A pure crystalline ethyl anthranilate azo derivative of UCB (AZO . UCB) was employed as a single h.p.l.c. reference standard for quantification of BMG and BDG. We demonstrate that: separation and quantification of biliary bile pigments are rapid (approximately 25 min); bile pigment concentrations ranging from 1-500 microM can be determined 'on line' by using 5 microliters of bile without sample pretreatment; bilirubin conjugates can be obtained preparatively in milligram quantities without degradation or contamination by other components of bile. H.p.l.c. analyses of a series of mammalian biles show that biliary UCB concentrations generally range from 1 to 17 microM. These values are considerably lower than those estimated previously by t.l.c. BMG is the predominant, if not exclusive, bilirubin conjugate in the biles of a number of rodents (guinea pig, hamster, mouse, prairie dog) that are experimental models of both pigment and cholesterol gallstone formation. Conjugated bilirubins in the biles of other animals (human, monkey, pony, cat, rat and dog) are chemically more diverse and include mono-, di- and mixed disconjugates of glucuronic acid, xylose and glucose in proportions that give distinct patterns for each species.
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78
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Matern H, Matern S, Gerok W. Formation of bile acid glucosides by a sugar nucleotide-independent glucosyltransferase isolated from human liver microsomes. Proc Natl Acad Sci U S A 1984; 81:7036-40. [PMID: 6239286 PMCID: PMC392071 DOI: 10.1073/pnas.81.22.7036] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
A heat-labile protein has been detected in microsomes from human liver which catalyzes the formation of glucosides of the bile acids chenodeoxycholic, deoxycholic, and ursodeoxycholic acids. This glucosyltransferase activity has been purified about 900-fold from human liver microsomes, resulting in homogeneity as determined by sodium dodecyl sulfate gel electrophoresis. The subunit molecular weight was calculated to be about 56,000. The enzyme was separated from bile acid UDP-glucuronosyltransferase [UDP-glucuronate beta-D-glucuronosyltransferase (acceptor-unspecific), EC 2.4.1.17] during purification and does not catalyze the formation of bile acid glucuronides. The purified glucosyltransferase utilizes lipophilic alkyl beta-D-glucopyranosides as artificial donor substrates and dolichyl phosphoglucose as natural donor for the transfer of glucose to bile acids and does not exhibit bile acid conjugating activity in the presence of sugar nucleotides such as UDP-glucose. The apparent Km values estimated for various alkyl beta-D-glucopyranosides decreased with increasing alkyl chain length from 680 X 10(-6) M for hexyl beta-D-glucopyranoside to 20 X 10(-6) M as estimated for decyl and dodecyl beta-D-glucopyranoside. The results suggest that a glucoside-conjugation pathway of bile acids exists in humans. This conjugation is catalyzed by a sugar nucleotide-independent glucosyltransferase and is therefore distinct from the known mechanisms of glycoside conjugation.
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79
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Burchell B, Blanckaert N. Bilirubin mono- and di-glucuronide formation by purified rat liver microsomal bilirubin UDP-glucuronyltransferase. Biochem J 1984; 223:461-5. [PMID: 6497857 PMCID: PMC1144319 DOI: 10.1042/bj2230461] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Highly purified bilirubin UDP-glucuronyltransferase from Wistar-rat liver, when reconstituted with Gunn-rat liver microsomes (microsomal fraction), was able to catalyse the conversion of unesterified bilirubin into both bilirubin monoglucuronide and diglucuronide. Under zero-order kinetic conditions for monoglucuronide formation, the fraction of bilirubin diglucuronide formed by incubation of bilirubin with the reconstituted highly purified transferase accounted for 18% of total bilirubin glucuronides, which was only slightly lower than the fraction of diglucuronides (23% of total bilirubin glucuronides) formed by incubation with hepatic microsomes in the presence of UDP-N-acetylglucosamine or Lubrol. The reconstituted purified enzyme also catalysed the UDP-glucuronic acid-dependent conversion of bilirubin monoglucuronide into diglucuronide and, when bilirubin was incubated with UDP-glucose or UDP-xylose, the formation of bilirubin glucosides and xylosides respectively. These results suggest that a single microsomal bilirubin UDP-glycosyltransferase may be responsible for the formation of bilirubin mono- and di-glycosides.
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80
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Vermeir M, Vanstapel F, Blanckaert N. Radioassay of UDP-glucuronyltransferase-catalysed formation of bilirubin monoglucuronides and bilirubin diglucuronide in liver microsomes. Biochem J 1984; 223:455-9. [PMID: 6437392 PMCID: PMC1144318 DOI: 10.1042/bj2230455] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A radioassay for specific determination of the rates of UDP-glucuronic acid-dependent conversion of bilirubin into the two isomeric (C-8, C-12) bilirubin monoglucuronides and bilirubin diglucuronide is described and illustrated by its application to rat liver microsomes. The method is based on measurement of the relative amounts of radiolabel in unesterified bilirubin and its mono- and di-esterified reaction products after incubation with [14C]bilirubin as substrate. This analysis is performed by the alkaline-methanolysis procedure, combined with one of two t.l.c. systems developed in order to enhance the sensitivity, accuracy and precision of the radioassay. Results for rates of total bilirubin glucuronide formation obtained with the new assay and the standard enzyme assay based on the ethyl anthranilate diazo-method were identical. However, the sensitivity of the latter technique is approx. 10-fold lower than that of the radioassay.
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81
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Gordon ER, Meier PJ, Goresky CA, Boyer JL. Mechanism and subcellular site of bilirubin diglucuronide formation in rat liver. J Biol Chem 1984. [DOI: 10.1016/s0021-9258(18)91040-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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82
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Wriston JC. Comparative biochemistry of the guinea-pig: a partial checklist. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1984; 77:253-78. [PMID: 6365427 DOI: 10.1016/0305-0491(84)90329-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A great deal is known about guinea-pig biochemistry, but the information is scattered and difficult to assemble. The guinea-pig also possesses a number of unusual biochemical features which add to its interest. For these reasons we have compiled a list of biochemical characteristics of the guinea-pig, organized in a series of tables, with brief discussions of some of the entries.
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83
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Abstract
The accurate determination of the types and amounts of bilirubin species in serum is important for diagnostic purposes as well as for therapeutic monitoring. However, of the determinations routinely performed in the clinical laboratory, those for bilirubins are not among the more accurate and exhibit significant method variability. In this review, the structural, stability, solubility, and albumin-binding properties of serum bilirubins are discussed with respect to their impact on analytical methods. Following a consideration of analytical standards, methods for the determination of unconjugated and conjugated bilirubins are reviewed and recent developments are evaluated. Finally, the present capabilities and future potential of the methods for producing information applicable to the development of new or improved methods of determination are summarized.
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84
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Gordon ER, Sommerer U, Goresky CA. The hepatic microsomal formation of bilirubin diglucuronide. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(17)43767-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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85
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Mottino AD, Guibert EE, Carnovale C, Morisoli LS, Rodriguez Garay EA. Formation of bilirubin monoglucuronide and diglucuronide in isolated rat hepatocytes. Effect of spironolactone. Biochem Pharmacol 1983; 32:3157-61. [PMID: 6639683 DOI: 10.1016/0006-2952(83)90198-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The formation of bilirubin monoglucuronide (BMG) and diglucuronide (BDG) was studied in isolated rat hepatocytes with appropriate viability. Isolated cells were obtained from normal rats and from rats pretreated with spironolactone (SP). A fixed number of cells (4.8 X 10(6)) was incubated in a medium containing uridine diphosphoglucuronic acid (UDPGA, 3.4 mM) and bilirubin (11.3 microM, 29 microM, 50 microM and 81 microM) for different time intervals (from 0 to 25 min). The pellet of cells and the supernatant fraction were subjected to alkaline methanolysis, and the proportions of BMG and BDG were estimated by thin-layer chromatography. No conjugates were detected at time O or in the absence of UDPGA in the incubation system. BMG and BDG were detected after 2 min of incubation and then they increased up to 15 min of incubation. Both conjugates were mostly found in the supernatant fraction, and a predominance of BMG was apparent. Normal cells also synthesized increasing amounts of BMG and BDG with the increase of bilirubin substrate concentration up to 50 microM. When hepatocytes from SP-treated rats were used, a more rapid rate of glucuronidation, that was mainly produced at the expense of BMG found in the supernatant fraction, was clear. The results probably indicate that enzymic conversion of BMG to BDG may be rate limiting in isolated hepatocytes although other possible mechanisms were not excluded.
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86
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Fevery J, Blanckaert N, Leroy P, Michiels R, Heirwegh KP. Analysis of bilirubins in biological fluids by extraction and thin-layer chromatography of the intact tetrapyrroles: application to bile of patients with Gilbert's syndrome, hemolysis, or cholelithiasis. Hepatology 1983; 3:177-83. [PMID: 6832709 DOI: 10.1002/hep.1840030207] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
A method was developed to extract quantitatively the bilirubins from bile, urine, serum, stool, and preparations from liver with a chloroform-ethanol mixture at pH 1.8 in the presence of ascorbic acid and NaCl. Extracted pigment was submitted to thin-layer chromatography, and the separated bilirubins were either immediately eluted and determined spectrophotometrically or individually converted to ethyl anthranilate azo derivatives for thin-layer chromatographic analysis of each isolated pigment band. Bilirubins in duodenal bile of eight healthy adults comprised 1.5 +/- 1.3% unconjugated bilirubin-IX alpha, 69 +/- 6% bilirubin diglucuronide, and 16 +/- 4% bilirubin monoglucuronides. Mixed diconjugates containing one glucuronosyl moiety and either one xylosyl or one glucosyl group amounted to 10 +/- 3%. Most samples (6 of 8) contained trace amounts (0.6 +/- 0.6%) of unconjugated bilirubin-IX beta, in agreement with nearly exclusive cleavage of heme at the alpha-meso position. The composition of the bilirubins in bile was normal in 6 patients with cholesterol gallstones, 4 with chronic hepatitis, and 3 with hemolysis. In duodenal bile of individuals with Gilbert's syndrome (n = 10), the concentration of bilirubin conjugates was comparable to that in healthy adults, but the proportion of bilirubin diglucuronides (52 +/- 8%) was decreased. The concentration of unconjugated bilirubin-IX alpha showed a fair positive correlation with that of bilirubin monoglucuronide and was increased in half of the patients with Gilbert's syndrome.
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87
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Bruss ML, Cornelius CE, Himes JA. Effect of bilirubin infusion on excretion of bilirubin and biliverdin in rabbits. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. A, COMPARATIVE PHYSIOLOGY 1983; 76:339-44. [PMID: 6139208 DOI: 10.1016/0300-9629(83)90335-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Intravenous infusion of bilirubin (BR) at 171 micrograms/min/kg into rabbits resulted in biliary concentration of BR increasing from 3.8 (control) to 243 mg/dl and BR excretion increasing from 1.7 to 66 micrograms/min/kg. BR infusion resulted in biliary concentrations of biliverdin (BV) increasing from 9.1 to 30 g/dl and BV excretion increasing from 4.2 to 8.2 micrograms/min/kg. BR infusion produced a progressive decline in bile flow. BV was the predominant bile pigment in control rabbits fed either an alfalfa-based or chlorophyll-free diet. These results imply that rabbits can oxidize BR to BV.
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88
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Adachi Y, Yamamoto T. Hepatic bilirubin-conjugating enzymes of man in the normal state and in liver disease. GASTROENTEROLOGIA JAPONICA 1982; 17:235-40. [PMID: 6214447 DOI: 10.1007/bf02776002] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Bilirubin UDP-glucuronyl transferase (BGT), bilirubin UDP-glucosyl transferase (BGLT) and bilirubin UDP-xylosyl transferase (BXT) activities were measured in wedge-biopsied liver specimens obtained from patients with various liver diseases, and compared with those in controls with normal liver histology. BGT was measured alone using needle biopsy liver specimens from the patients with Gilbert's syndrome (15 patients). Rotor's syndrome (one) and posthepatitic hyperbilirubinemia (3). BGT was decreased to about 30% of controls in Gilbert's syndrome, but showed no change in posthepatitic hyperbilirubinemia and Rotor's syndrome. About 90% decrease in BGT, and BGLT and BXT were observed in Crigler-Najjar syndrome type II (3 patients). In patients with cholelithiasis and chronic hepatitis, statistically significant changes of these three enzymes were not observed, except the statistically significant increase in BGT activity in chronic hepatitis. Slight increases in BGT and BXT activities were observed in anicteric cases with cholelithiasis. The ratio of BGT, BGLT and BXT activities in controls was 1:0.50:0.98 (expressed as "per mg protein"). Slight differences existed between the ratios of BGT, BGLT and BXT in various liver diseases, and this may suggest the separate identities of BGLT and BXT from BGT. Determination of bilirubin-conjugation is essential in the diagnosis of Gilbert's syndrome and Crigler-Najjar syndrome type II, but shows no specific change in the other chronic liver diseases.
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89
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Morisoli LS, Mottino AD, Pellegrino JM, Guibert EE, Rodriguez Garay EA. Effect of spironolactone on bilirubin metabolism in rat liver and small intestinal mucosa. Biochem Pharmacol 1982; 31:1469-74. [PMID: 6807322 DOI: 10.1016/0006-2952(82)90368-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
In vitro and in vivo experimental models were designed for the study of the effect of spironolactone (SP) on bilirubin metabolism in rat liver and small intestinal mucosa. In vitro studies included uptake of bilirubin by liver slices and intestinal sheets, determination of glucuronyltransferase activity in mucosal homogenates, and the handling of bilirubin by the isolated perfused liver after bilirubin overload. In vitro studies were carried out to measure the plasma disappearance rate of bilirubin and to determine the extent of bilirubin conjugation and biliary excretion of the pigment infused intravenously. The results obtained suggested that the mechanisms involved in the uptake of bilirubin by tissues were not influenced by SP pretreatment. Glucuronyltransferase activity in the small intestinal mucosa was significantly induced by SP, as previously observed in rat liver. Isolated perfused livers from SP-treated rats, as well as treated living rats, exhibited a greater than normal capacity for bilirubin excretion into bile at the expense of bilirubin diglucuronide. Conjugated bilirubin in the small intestinal mucosa of rats infused with unconjugated pigment was also increased after SP pretreatment. The results favoured the conclusion that SP is an inducer of bilirubin conjugation in the livers as well as in extrahepatic tissues, such as the small intestinal mucosa.
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90
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Cole KD, Little GH. Isocratic high-performance liquid chromatography of bile pigments. JOURNAL OF CHROMATOGRAPHY 1982; 227:503-9. [PMID: 7061661 DOI: 10.1016/s0378-4347(00)80404-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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91
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Sieg A, van Hees GP, Heirwegh KP. Uridine diphosphate-glucuronic acid-independent conversion of bilirubin monoglucuronides to diglucuronide in presence of plasma membranes from rat liver is nonenzymic. J Clin Invest 1982; 69:347-57. [PMID: 7056852 PMCID: PMC370984 DOI: 10.1172/jci110458] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
TWO ROUTES HAVE BEEN PROPOSED FOR CONVERSION OF BILIRUBIN MONOGLUCURONIDE TO THE DIGLUCURONIDE: glucuronyl transfer (a) from UDP-glucuronic acid to bilirubin monoglucuronide, catalyzed by a microsomal UDP-glucuronyltransferase, and (b) from one molecule of bilirubin monoglucuronide to another (transglucuronidation), catalyzed by an enzyme present in liver plasma membranes. The evidence regarding the role of the latter enzyme for in vivo formation of bilirubin diglucuronide is conflicting. We therefore decided to reexamine the transglucuronidation reaction in plasma membranes and to study the conversion of bilirubin monoglucuronide to diglucuronide in vivo. Purified bilirubin monoglucuronide was incubated with homogenates and plasma membrane-enriched fractions from liver of Wistar and Gunn rats. Stoichiometric formation of bilirubin and bilirubin diglucuronide out of 2 mol of bilirubin monoglucuronide was paralleled by an increase of the IIIalpha- and XIIIalpha-isomers of the bilirubin aglycone, thus showing that dipyrrole exchange, not transglucuronidation, is the underlying mechanism. Complete inhibition by ascorbic acid probably reflects intermediate formation of free radicals of dipyrrolic moieties. The reaction was nonenzymic because it proceeded independently of the protein concentration and heat denaturation of the plasma membranes did not result in decreased conversion rates. Collectively, these findings show spontaneous, nonenzymic dipyrrole exchange when bilirubin monoglucuronide is incubated in the presence of rat liver plasma membranes. Because bilirubin glucuronides present in biological fluids contain exclusively the bilirubin-IXalpha aglycone, formation of the diglucuronide from the monoglucuronide by dipyrrole exchange does not occur in vivo. Rapid excretion of unchanged bilirubin monoglucuronide in Gunn rat bile after injection of the pigment provides confirmatory evidence for the absence of a UDP-glucuronic acid-independent process.
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92
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Cornelius CE. The use of nonhuman primates in the study of bilirubin metabolism and bile secretion. Am J Primatol 1982; 2:343-354. [DOI: 10.1002/ajp.1350020403] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/1981] [Accepted: 12/01/1981] [Indexed: 11/10/2022]
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93
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Cornelius CE. Hepatic Bilirubin-IX- α -Glycosyltransferase Activities in Animals Excreting Primarily Biliverdin into Bile. Vet Clin Pathol 1981; 10:27-31. [PMID: 15311383 DOI: 10.1111/j.1939-165x.1981.tb00801.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A wide variation was observed in hepatic bilirubin-IX-alpha uridine diphosphate (UDP) glucuronyl, glucosyl and xylosyl transferase activities among yellow rat snakes, pin fish, chickens, turkeys, sea turtles, alligators, nutria and rats. Lower hepatic enzyme activities were observed in fish, snakes, turtles, and avian species with intermediate enzyme activities present in the livers of nutria and alligators. Hepatic glycosyltransferase activities were greater in the biliverdin-excreting species which are known to excrete readily an exogenous bilirubin load. Hepatic enzyme activities and the biliary transport maxima of bilirubin-IX-alpha are closely correlated.
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Affiliation(s)
- C E Cornelius
- Department of Medical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida 32610
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Blanckaert N, Gollan J, Schmid R. Mechanism of bilirubin diglucuronide formation in intact rats: bilirubin diglucuronide formation in vivo. J Clin Invest 1980; 65:1332-42. [PMID: 6773983 PMCID: PMC371471 DOI: 10.1172/jci109797] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Although it is well established that bilirubin monoglucuronide is formed in the liver from bilirubin by a microsomal bilirubin uridine diphosphate (UDP)-glucuronosyltransferase, the subcellular site of conversion of monoglucuronide to diglucuronide and the molecular mechanism involved in diglucuronide synthesis have not been identified. Based on in vitro studies, it has been proposed that two fundamentally different enzyme systems may be involved in diglucuronide synthesis in rat liver: (a) a microsomal UDP-glucuronosyltransferase system requiring UDP-glucuronic acid as sugar donor or (b) a transglucuronidation mechanism that involves transfer of a glucuronosyl residue from one monoglucuronide molecule to another, catalyzed by a liver plasma membrane enzyme. To clarify the mechanism by which bilirubin monoglucuronide is converted in vivo to diglucuronide, three different experimental approaches were used. First, normal rats were injected with either equal amounts of bilirubin-IIIalpha [(14)C]monoglucuronide and unlabeled bilirubin-XIIIalpha monoglucuronide, or bilirubin-XIIIalpha [(14)C]monoglucuronide and unlabeled bilirubin-IIIalpha monoglucuronide. Analysis of radiolabeled diglucuronide excreted in bile showed that [(14)C]glucuronosyl residues were not transferred between monoglucuronide molecules. Second, in normal rats infused intravenously with dual-labeled [(3)H]bilirubin [(14)C]monoglucuronide, no transfer or exchange of the [(14)C]glucuronosyl group between injected and endogenously produced bilirubin monoglucuronide could be detected in the excreted bilirubin diglucuronide. Third, in homozygous Gunn rats, injected (14)C-labeled or unlabeled bilirubin mono- or diglucuronides were excreted in bile unchanged (except that diglucuronide was hydrolyzed to a minor degree). This indicates that Gunn rats, which lack bilirubin UDP-glucuronosyltransferase activity, are unable to convert injected monoglucuronide to diglucuronide. Collectively, these findings establish that a transglucuronidation mechanism is not operational in vivo and support the concept that bilirubin diglucuronide is formed by a microsomal UDP-glucuronosyltransferase system.
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95
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Blanckaert N. Analysis of bilirubin and bilirubin mono- and di-conjugates. Determination of their relative amounts in biological samples. Biochem J 1980; 185:115-28. [PMID: 7378044 PMCID: PMC1161276 DOI: 10.1042/bj1850115] [Citation(s) in RCA: 161] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
1. A novel method for determination of the relative amounts of unconjugated bilirubin and sugar mono- and di-conjugates of bilirubin in biological samples, including serum, is described and illustrated by its application to the analysis of bilinoids in rat bile. 2. The method is based on specific conversion of the carbohydrate conjugates of bilirubin into the corresponding mono- or di-methyl esters by base-catalysed transesterification in methanol. Under the selected reaction conditions, unconjugated biliru-in remains intact and no dipyrrole exchange in the bilinoids is detectable; transesterification of bilirubin mono- or di-glucuronide is virtually complete (approx. 99%), and sponification is negligible (less than 1%); recovery of the pigments is approx. 95%. 3. The reaction products bilirubin and its methyl esters are separated by t.l.c. and determined spectrophotometrically; the two isomeric bilirubin-IX alpha monomethyl esters are separated and therefore can be determined individually. 4. Reference bilirubin mono- and di-methyl esters have been synthesized and characterized, and the two isomers of bilirubin-IX alpha monomethyl ester and bilirubin dimethyl ester were obtained individually, in crystalline form. 5. With this new method, virtually all bilinoids (over 99%) in normal rat bile have been found to be conjugated, with diconjugates (71%) predominating. A significantly increased proportion of monoconjugates is present in bile collected from heterozygous Gunn rats or from normal rats that were refused with large amounts of bilirubin.
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Cornelius CE, Bruss ML. Hepatic Bile Pigment Excretion and Erythrocyte Turnover in Various Species. Vet Clin Pathol 1980; 9:15-20. [PMID: 15314772 DOI: 10.1111/j.1939-165x.1980.tb00887.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Endogenous bile pigment excretory rates have now been recorded in fifteen species, and the following review briefly compares the excretion per unit of body weight in animals of varying sizes, attempts to determine if any correlation exists between bile flow and endogenous pigment excretion and discusses bile pigment excretion in relation to mean erythrocyte survival time and metabolic rate. Graphs and one table illustrating pigment metabolism and erythrocyte replacement are presented. Differences between animals excreting primarily biliverdin as opposed to bilirubin are discussed, with special attention being given throughout the article to mammals and their individual differences. Accepted theory concludes that the rate of endogenous bile pigment excretion is primarily dependent upon hemoglobin catabolism. However, further studies will be necessary to clarify basic physiological mechanisms in order to substantiate any theory concerning the correlation of erythrocyte turnover with metabolic rates.
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Affiliation(s)
- C E Cornelius
- Departments of Medical Sciences and Metabolism, College of Veterinary Medicine University of Florida, Gainesville, Florida 32610
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Gaidano G, Angeli A, Rovero E, Rolfo E, Rosatti P, Anselmo P. Plasma bile pigment conjugation modalities in icterus syndromes of various origin. LA RICERCA IN CLINICA E IN LABORATORIO 1979; 9:379-86. [PMID: 545646 DOI: 10.1007/bf02904574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Plasma azopigments derived from conjugated bilirubin were analyzed by thin-layer chromatography according to HEIRWEGH et al. in 14 cases of obstructive jaundice and in 11 of acute hepatitis. The chromatographic patterns were compared with those obtained from azopigments derived from 8 normal bile samples. The plasma pigment patterns did not differ from those of the bile in number and chromatographic mobility of the spots. However, the quantitative percentages of the plasma azopigments were significantly modified: the alpha 0 fraction (free azodipyrrolic pigment) increased in both icteric syndromes, while the delta fraction (mainly glucuronide azopigment) decreased. Moreover, the behavior of two closed components of the delta group showed significant differences in both icteric syndromes. It can be postulated that the synthesis of bilirubin diconjugates decreases both in hepatocellular and cholestatic jaundice, while monoglucuronidated as well as saccharide and glucoside conjugates increase. In cholestatic jaundice the conjugation with glucuronic acid mainly takes place in the normal way, whereas compounds with different features are formed in hepatitis.
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Mottino AD, Rassero JA, Rodriguez Garay EA. Effect of spironolactone on bilirubin conjugation by the rat liver. Biochem Pharmacol 1979; 28:2215-7. [PMID: 497003 DOI: 10.1016/0006-2952(79)90208-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Heirwegh KP, Compernolle F. Micro-analytic detection and structure elucidation of ester-glycosides. Biochem Pharmacol 1979; 28:2109-14. [PMID: 387039 DOI: 10.1016/0006-2952(79)90191-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Abstract
An unconjugated hyperbilirubinemia has been observed in all species of normal indigo snakes. The plasma clearance of large organic anions such as sulfobromophthalein and unconjugated bilirubin was markedly delayed when compared to other snake species. Endogenous bile flow and biliverdin and bilirubin excretory rates and the excretion of bile pigments after a bilirubin load were measured in various snakes. The indigo snake represents a new animal model in which to study mechanisms important to hepatic anion uptake and biliary transport.
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