Bromsulphthalein and indocyanine green elimination from plasma, and urinary bromsulphthalein excretion, in normal cats.

The elimination of bromsulphthalein (BSP) and indocyanine green (ICG) from plasma and urinary excretion of BSP were investigated in healthy cats. At 5 mg kg-1, BSP elimination fitted a two-compartment open model, with mean t1/2 beta of 7.1 (SD 2.5) minutes. A tendency for slower elimination of BSP at 10 mg kg-1 suggested saturation of excretory mechanisms, while at 2 mg kg-1 accurate dosing and assay of low BSP concentrations were difficult. Urinary recovery of BSP at 5 mg kg-1 was 0.01 to 0.13 per cent of the total dose. Plasma ICG (0.5 mg kg-1) data fitted a one-compartment open model, with mean t1/2 2.7 (SD 1.0) minutes. In cats, retention tests are more attractive than clearance tests because fewer blood collections are necessary. Proposed reference values are under 3.6 per cent retention of BSP (5 mg kg-1) at 30 minutes and under 17.5 per cent retention of ICG (0.5 mg kg-1) at 15 minutes. At present economic and technical factors favour BSP over ICG.

Clearance of bromosulphthalein from plasma as a measure of hepatic function in normal horses and in horses with liver disease.

Single intravenous injections of bromosulphthalein (BSP) were given to horses and the change in plasma concentration of BSP with time was analysed by computer to obtain the proportionality transfer constants 'a', 'h' and 'b'. No age, weight or sex differences in BSP clearance were found in normal horses. The technique was non-invasive, repeatable and suitable for conscious animals. The measurement of the transfer constants 'a', 'h' and 'b', helped to provide an accurate guide to diagnosis and prognosis of liver disease.

Effects of morphine and clonidine on sulphobromophthalein disposition in mice.

Levels of sulphobromophthalein (BSP) in plasma and liver were elevated by the opiate, morphine, and by the alpha 2-adrenoceptor agonist, clonidine. Neither morphine, 1 mg kg-1, nor clonidine, 0.01 mg kg-1, affected BSP levels significantly. When given together at these doses, they caused BSP levels in plasma and liver to be raised. At 20 mg kg-1, the effect of morphine on BSP levels was maximal, as was that of clonidine, 1.0 mg kg-1. However, the effect of these drugs given together on plasma BSP exceeded the maximal effect of either alone. Yohimbine, an alpha 2-adrenoceptor antagonist, did not affect BSP levels, nor did the opiate antagonist, naloxone. Each of these antagonists reversed the hepatobiliary effects of its respective agonist, as shown by return of BSP levels to those of saline-treated mice. Yohimbine did not reverse morphine, nor did naloxone reverse clonidine. The additive effects of morphine and clonidine and the specificities of their respective antagonists strongly suggest the involvement of discrete receptors mediating their essentially identical hepatobiliary effects.

Bromsulfophthalein clearance and aminopyrine test in patients with Gilbert's syndrome.

Bromsulfophthalein (BSP) clearance and aminopyrine breath tests were performed in 13 patients with Gilbert's syndrome (GS) and six healthy volunteers. The BSP clearance was significantly lower in the GS patients (1.28 +/- 0.37 dl/min) than in the healthy volunteers (1.98 +/- 0.45 dl/min). The difference in clearance was not due to a significant difference in volume of distribution. The 13 patients with Gilbert's syndrome could be divided into three groups according to their BSP disappearance curves: in 7 the curves were normal; another 3 patients the disappearance rate of BSP was normal at the beginning, but became abnormally low later on; and in the last 3 patients, an abnormal BSP disappearance rate was observed during the whole experiment. Kinetic analysis of these BSP disappearance curves indicated increased regurgitation of BSP from the liver to the blood in the second group and defective hepatic BSP uptake in the third group. The aminopyrine breath test also demonstrated heterogeneity among the GS patients. There was no correlation between the impaired BSP clearance and the aminopyrine breath test.

The measurement of liver blood flow in conscious calves.

Observations were made following single I.V. injections or during continuous I.V. infusions of sulphobromophthalein (BSP) in three Jersey calves (3-5 months of age) which had an indwelling hepatic vein catheter, surgically implanted under general anaesthesia. Simultaneous sampling of blood from a peripheral (jugular) vein and an hepatic vein enabled calculations of hepatic plasma flow (E.H.P.F.) based on the Fick principle. Estimates of E.H.P.F. in nine single injection experiments gave a mean flow of 38.6 ml X min-1 X kg-1 compared to 32.6 ml X min-1 X kg-1 estimated in seven continuous infusion experiments. The over-all mean haematocrit in the three calves was 30.0% and the E.H.P.F. values are equivalent to hepatic blood flows of 55 and 47 ml X min-1 X kg-1 respectively. In thirteen out of fourteen experiments the plasma clearance of BSP in jugular vein blood after a single I.V. injection of 5 mg BSP X kg-1 body weight was best fitted by a double exponential model of distribution of BSP. Parameters from these exponentials were used to calculate E.H.P.F. by the method of Clarkson, Hardy-Smith & Richards (1976) and gave values of 11.3 ml X min-1 X kg-1, clearly indicating that the method cannot be applied in conscious calves.

Effect of benzyl chloride on rat liver functions.

Benzyl chloride (BCL) is extensively used in industry for the manufacture of dyes, perfumes, and pharmaceutical products. A previous study from this laboratory revealed the presence of liver steatosis of the microvesicular type and central focal inflammation in rats following the inhalation of BCL. This study was conducted to investigate the hepatotoxicity of intravenous (iv) BCL in rat. BCL (250, 25, and 0 micrograms/kg) was administered (iv) to rats, and serum enzyme tests were used to evaluate hepatic injury. After 10 min from BCL administration, serum glutamic-pyruvic transaminase and lactic dehydrogenase activities were significantly increased compared to the control group, while the values returned to normal within 1 h from the administration of BCL. Also, ornithine carbamyltransferase enzyme activity was significantly increased and reached a maximum as early as 0.5 h from the administration of BCL. Hepatic excretory function was investigated by the clearance of bromosulfophthalein (BSP) after 0.5 and 24 h from the administration of BCL. The clearance of BSP in both treatments was significantly slower compared to control group throughout the 24 h studied. Furthermore, BCL significantly decreased liver and blood glutathione values. This study revealed that BCL has the potential to cause hepatomalfunction.

Displacement of sulphobromophthalein from albumin and fatty-acid-binding protein by oleic acid.

The absorption of sulphobromophthalein changes upon addition of bovine serum albumin or fatty-acid-binding protein at pH 8.4. The sulphobromophthalein spectrum is changed most drastically after the addition of albumin than in the presence of fatty-acid-binding protein isolated from rat liver, suggesting as a first approximation that binding capacity of albumin is much higher than that of fatty-acid-binding protein. When both soluble proteins are saturated with oleic acid it is observed a decrease in the binding of sulphobromophthalein which suggests that the presence of fatty acids in those soluble proteins may affect the binding of other ligands.

Hepatobiliary transport of indocyanine green and sulfobromophthalein in fed and fasted horses.

Fasting is associated with unconjugated hyperbilirubinemia in several species, including the horse. Studies in ponies showed that a 3-day fast decreased plasma clearance of bilirubin, cholic acid, and sulfobromophthalein (BSP). Since these organic anions are conjugated with different substrates, it is possible that observed differences in plasma clearance result from a general decrease in hepatic conjugating capacity during the animals' fasting. To test this hypothesis, the effects of a 3-day fast on plasma clearance of IV injected BSP (4.4 to 5.1 mg/kg), which is conjugated to glutathione, and indocyanine green (ICG; 0.8 to 1.1 mg/kg), which is not conjugated, were studied in 10 healthy horses and 2 ponies with diverted enterohepatic circulations (indwelling T tubes). Blood samples were obtained for 30 minutes after injection, and bile samples from ponies were obtained for 3 hours. Fasting increased plasma bilirubin concentration in all animals studied (from 1.03 +/- 0.337 mg/dl in control animals to 3.49 +/- 1.01 mg/dl in fasted animals). Kinetic values of ICG disappearance were determined from single exponential functions, and those for BSP were determined from both single and curvilinear (2-exponential) functions. Plasma clearance of BSP in fed horses (8.65 +/- 1.02 ml X min-1 X kg-1) was greater than clearance of ICG (3.54 +/- 0.67 ml X min-1 X kg-1), results similar to those reported in dogs, cats, rats, and persons. Fasting significantly decreased fractional plasma disappearance rate of both BSP (-36%) and ICG (-58%) and similarly reduced plasma clearance (BSP,-48%; ICG,-55%).(ABSTRACT TRUNCATED AT 250 WORDS)

Sex differences in the hepatic uptake of sulphobromophthalein in the rat.

Sex difference in the hepatic uptake of sulphobromophthalein (BSP) was investigated in male and female rats in three different experimental models. In the intact animal the BSP plasma disappearance rate was significantly higher (P less than 0.01) in females than in males when 0.15 or 1.5 mumol/kg body wt. was injected. Comparable values were found at the highest BSP dose (15 mumol/kg body wt.) used. In the perfused liver, the first-pass hepatic extraction and the uptake velocity were significantly higher (P less than 0.001) in female rats at low BSP doses (0.3-750 mumol/g of liver) whereas identical values were found at higher concentrations. In hepatocytes isolated by collagenase perfusion, the BSP uptake occurs via two different uptake sites in both sexes. The Km of the high affinity sites was lower in females than in males (3.67 +/- 0.58 vs 7.24 +/- 0.68 mumol/l, P less than 0.001) whereas Vmax. showed comparable values (2.70 +/- 0.36 vs 2.47 +/- 0.45 nmol of BSP/mg of protein, NS). In contrast, no difference was found in the kinetic parameters of the low affinity sites (Km 50.6 +/- 31.1 vs 61.0 +/- 17.5 mumol/l; Vmax. 21.9 +/- 13.2 vs 25.0 +/- 3.6 nmol of BSP/mg of protein, mean +/- SD, NS, females and males respectively). Taken together these data show that low doses of BSP are taken up by the liver more efficiently in female than in male rats and are consistent with a sex-related difference in the affinity but not in the number of the BSP high affinity uptake sites.

Opioid effects on hepatic disposition of dyes in mice.

Morphine administration acutely reduced plasma clearance of sulfobromophthalein (BSP) in mice and increased hepatic retention of this dye. Increasing morphine doses from 5 to 40 mg/kg s.c. progressively raised plasma and liver BSP levels. Morphine-treated mice, warmed to reverse hypothermia, still had higher plasma and liver BSP levels. The narcotic also raised plasma levels of two dyes which are not conjugated, indocyanine green and dibromosulfophthalein. Naloxone reversed morphine-induced elevation of plasma BSP levels. In bile duct-ligated mice, plasma BSP levels were very high but hepatic BSP levels remained low, both after saline or morphine. Thus, the effects of morphine on BSP disposition differed from those of biliary occlusion. BSP content in bile was reduced by morphine, as dye levels were raised in plasma and hepatic parenchyma. In bile duct-cannulated mice morphine increased BSP levels in plasma and liver whereas reducing the amount of dye eliminated in bile.

Hepatic transport and biliary excretion of sulfobromophthalein in aflatoxin B1-treated rats.

The effects of a single dose of aflatoxin B1 (AFB1) on sulfobromophthalein (BSP) plasma disappearance, hepatic transport maximum (Tm), and relative storage capacity (S), were examined in rats 48 hr after AFB1 injection. BSP plasma concentration decay was delayed, and the BSP biliary excretion was diminished in treated animals. S and Tm values were unaltered. However, the Tm was reached in treated rats at a higher infusion rate. A Lineweaver-Burk plot of BSP biliary excretion rate vs BSP serum concentration curve showed a higher apparent Km in the AFB1-treated rats.

Organ tolerance of non-steroidal anti-inflammatory drugs: effect on liver cells.

Experimental studies in mice and in rats showed the good tolerance of a new non-steroidal anti-inflammatory drug, flunoxaprofen, by normal and CCl4 damaged liver. The activity of an enzyme-inducing drug, such as phenobarbital, showed a greater increase after pretreatment with indomethacin than with flunoxaprofen or benoxaprofen. High doses of benoxaprofen and indomethacin significantly decreased bromosulphonphthalein excretion in rats with normal or CCl4 damaged liver; the effect was not observed with flunoxaprofen administered at the same dose as benoxaprofen. Moreover, benoxaprofen and indomethacin but not flunoxaprofen induced a significant increase of some serum liver enzymes in CCl4 poisoned rats.

Altered clearance of sulphobromophthalein (BSP) in patients with pancreatic disease.

The components of the plasma disappearance curve of sulphobromophthalein--Ki, K2, K1--were analysed in 26 patients with pancreatic disease. The mean corrected initial disappearance rate constant, K1, in the patients significantly exceeded the published mean value in controls: all but four patients had a value equal to or higher than the upper limit of the reference range (mean +2 SD). The mean uncorrected initial disappearance rate constant, Ki, in the patients was not significantly different from the mean in controls but the mean of the second exponential, K2, was significantly reduced. At least one abnormality in the test (Ki, K2, K1) was present in 24 of the 26 patients studied (93%), although clinical evidence of hepatic dysfunction was generally unimpressive. The possible implications of the results are discussed with reference to previous studies.

Plasma clearance of sulfobromophthalein and its interaction with hepatic binding proteins in normal and analbuminemic rats: is plasma albumin essential for vectorial transport of organic anions in the liver?

To investigate a possible function of plasma albumin in the vectorial transport of organic anions by the liver, the plasma disappearance of sulfobromophthalein (BSP) and its interaction with plasma and liver cytosolic proteins were studied in normal rats and mutant Nagase analbuminemic rats (NAR). After intravenous administration of BSP, plasma BSP decreased rapidly in both NAR and control animals: plasma clearance values of BSP in NAR and controls were 12.45 and 7.40 ml/min per kg, respectively. Gel exclusion Sephadex G-100 chromatography of BSP with control rat serum revealed a protein peak in the void volume and another in the albumin fraction. BSP chromatographed exclusively with the albumin fraction; binding of BSP to plasma albumin occurred stoichiometrically. Similar studies with NAR serum revealed a single protein peak, in the void volume; a small amount of BSP chromatographed with this protein peak. The amount of BSP that chromatographed with NAR serum protein(s) was 8% of that with control rat serum albumin. Sephadex G-100 chromatography of BSP with control rat liver cytosol revealed four peaks of protein-bound BSP in fractions corresponding to the void volume (fraction X), albumin, glutathione S-transferases (fraction Y, Mr 45,000), and fraction Z (Mr 12,000); fraction Y was the major component of BSP binding. Gel chromatography of NAR liver cytosol with BSP revealed three BSP peaks, fractions X, Y, and Z; fraction X was the major component of BSP binding. Total BSP binding by 30 mg of hepatic cytosolic proteins was 4.5 nmol for controls and 10.4 nmol for NAR. Isoelectric focusing of liver cytosol revealed no quantitative or qualitative differences in glutathione S-transferase isozymes between control and mutant animals. Intravenously administered BSP (5 mumol/kg) rapidly appeared in bile as the free form and the glutathione conjugate in normal rats and NAR; 41% and 57% of injected BSP was excreted within 60 min in NAR and control rat bile, respectively. These results indicate that binding of BSP to plasma albumin is not indispensable to transhepatocyte transport of BSP in vivo.

Preparation and metabolism of 125I-sulfobromophthalein.

Metabolism of 125I-sulfobromophthalein (BSP) prepared by the chloramine-T method was studied in rats. 125I-BSP is removed rapidly from the circulation. However, as compared to BSP, its plasma clearance and biliary excretion are delayed, and its accumulation in the liver is prolonged. Although BSP and 125I-BSP show similar binding to albumin in serum, their binding properties to liver cytosolic proteins and to the liver cell plasma membrane organic anion binding protein (OABP) differ. In contrast to the X-, Y- and Z-protein binding of BSP, 125I-BSP binds predominantly to a high molecular weight protein and only a small proportion of 125I-BSP binds to OABP.

Bromsulphalein plasma kinetics after obstruction of the common bile duct in rats: curve fitting with a programmable calculator.

Plasma kinetics of bromsulphalein (BSP) after a single injection into the bloodstream of the rat with total obstruction of the common bile duct was examined. The concentrations of BSP were determined colorimetrically. A monoexponential plus a general first-degree function in time with four unknown parameters was fitted. Two programs were developed for the Texas Instruments 59 programmable calculator to estimate the values of all the parameters by an iteration procedure. The programs executed at about twice normal speed.