In vitro kinetics of hepatic albendazole sulfoxidation in channel catfish (ictalurus punctatus), tilapia (oreochromis sp.), rainbow trout (oncorhynchus mykiss) and induction of erod activity in abz-dosed channel catfish
J. vet. Pharmacol. Therap. doi: 10.1111/j.1365-2885.2009.01056.x
In vitro kinetics of hepatic albendazole sulfoxidation in channel catfish(Ictalurus punctatus), tilapia (Oreochromis sp.), rainbow trout (Oncorhynchusmykiss) and induction of EROD activity in ABZ-dosed channel catfish
Gonza´lez, J. F., Shaikh, B., Reimschuessel, R., Kane, A. S. In vitro kinetics of
hepatic albendazole sulfoxidation in channel catfish (Ictalurus punctatus), tilapia
(Oreochromis sp.), rainbow trout (Oncorhynchus mykiss) and induction of EROD
activity in ABZ-dosed channel catfish. J. vet. Pharmacol. Therap. doi: 10.1111/
Liver microsomes from market-size (n = 6) rainbow trout, channel catfish and
*School of Veterinary Medicine & Animal
tilapia were used to investigate in vitro biotransformation kinetics of
Science Universidad Nacional de Colombia,Bogota´, Colombia; Center for Veterinary
albendazole (ABZ). ABZ was transformed to a single metabolite, ABZ sulfoxide
(ABZ-SO). Catfish displayed the highest maximal velocity (Vmax = 264.0 ±
58.6 pmols ABZ-SO ⁄ min ⁄ mg protein) followed by tilapia (112.3 ± 8.2) and
Health & Health Professions – University of
rainbow trout (73.3 ± 10.3). Vmax in catfish was significantly different
(P < 0.05) from the other two species. Michaelis–Menten constant (Km) values(lM) varied significantly among the species: rainbow trout (3.9 ± 0.5), tilapia(9.2 ± 1.7) and catfish (22.0 ± 3.2). However, Vmax ⁄ Km ratios showed nodifference among the three species, making them equally efficient performingthis phase I biotransformation reaction. In a second series of experiments,channel catfish (n = 6 per treatment) were dosed in vivo with gel-foodcontaining ABZ (10 mg ⁄ kg, p.o.). Fish were killed at 24, 48, 72 and 120 hafter dosage. Control fish were fed ABZ-free feed. Induction of ethoxyresorufin-o-deethylase activity was significant (P < 0.05) in all ABZ-dosed treatments ascompared with controls.
(Paper received 17 September 2008; accepted for publication 16 December 2008)
Jaime Fernando Gonza´lez, Calle 23 A No. 59-72 T4 Ap 704 Bogota´, Colombia. E-mail: jfgonzalezma@unal.edu.co, jaimefgonzalez@gmail.com
et al., 1995), rabbits (Li et al., 1995), sheep (Cristo`fol et al.,1998; Chiap et al., 2000), goats (Delatour et al., 1991b), cattle
Albendazole (ABZ, [5-(propylthio)-1H-benzimidazol-2-yl]-carba-
(Lanusse & Prichard, 1992), chicken (Csiko et al., 1996),
mate), is a broad spectrum anthelmintic used for the treatment of
humans (Rawden et al., 2000) and helminth parasites (Solana
liver flukes, tapeworms and lung and gastrointestinal round
et al., 2001). Residue depletion of ABZ and its main metabolites
worms in human (Cook, 1990; Ottesen et al., 1999) and
after oral administration in rainbow trout, tilapia, Atlantic
veterinary medicine (Campbell, 1990). ABZ and other benzim-
salmon and channel catfish has been studied by Shaikh et al.
idazoles derivatives have been used successfully in experimental
trials to treat fish parasites such as microsporidia (Schmahl &
Albendazole and other benzimidazoles have been linked to
inducing effects of phase I and II biotransformation enzymes.
In a wide variety of species, oxidative bioactivation of ABZ
ABZ is reported to induce CYP1A-mediated activity [e.g.,
yields a first phase I metabolite, ABZ-sulfoxide (ABZ-SO) and is a
ethoxyresorufin-o-deethylation (EROD)] and protein content in
critical step for the expression of the anthelmintic activity. A
rats (Souhaili-ElAmry et al., 1988; Asteinza et al., 2000;
second sulphoxidation produces albendazole sulphone (ABZ-
Baliharova´ et al., 2003) and in human microsomes and
SO2), a pharmacologically inactive metabolite. A third biologi-
human hepatoma cell (HepG2) cultures (Rolin et al., 1989).
cally inactive metabolite, ABZ-2-aminosulfone (ABZ-2-NH2SO2),
Induction of S9 fraction activity, specifically EROD, MROD,
is produced through the deacetylation of ABZ-SO2 (Gottschall
pentoxyresorufin-o-dealkylation (PROD) and benzyloxyresoru-
et al., 1990). ABZ biotransformation metabolites have been
fin-o-dealkylation (BROD) activities and protein contents of rat
studied in mice (Douch & Buchanan, 1979), pigs (Souhaili-
livers after intraperitoneal ABZ injection is reported by
ElAmry et al., 1987), dogs (Delatour et al., 1991a), rats (Moroni
Escobar-Garcı´a et al. (2001). Besides CYP1A induction, ABZ
Ó 2009 Blackwell Publishing Ltd. No claim to original US government works
induces to a lesser extent CYP2A6, CYP2E1 (Souhaili-ElAmry
The microsomes were resuspended with 1 mL SET buffer
et al., 1988), CYP2B1 and CYP2B2 (Asteinza et al., 2000) and
(pH = 7.4) per gram of wet liver. Both cytosolic and microsomal
CYP3A4 (Souhaili-ElAmry et al., 1988; Asteinza et al., 2000)
fractions were stored at )80 °C for no longer than 3 months
in rats. ABZ has also been reported to induce phase II
until performing the assays. Protein was measured using the
BCA protein assay kit (Pierce – 23227, Rockford, IL, USA) based
activity in humans (Rolin et al., 1989) and glutathione-s-
on the colorimetric reaction with bicinchoninic acid (Vodicnik
transferase (GST) in mice serum and muscle (Derda et al.,
In vitro metabolism of drugs in fish can help provide scientific
evidence linking similarities in drug metabolism among piscinespecies. This study investigated in vitro kinetics of ABZ hepatic
Microsomal fractions from channel catfish, tilapia and rainbow
biotransformation in three aquaculturally relevant finfish spe-
trout specimens were used for ABZ in vitro metabolism according
cies: tilapia, channel catfish and rainbow trout. A second series
to a modified method from Rawden et al. (2000). Phosphate
of experiments examined the induction of phase I (EROD, PROD,
buffer (0.1 M), microsomes (100-lg protein), ABZ (1–30 lM)
BROD) and phase II GST activities after ABZ dosage (10 mg ⁄ kg
(Sigma A-4673, St Louis, MI, USA) and NADPH (1 mM,
p.o.) in channel catfish killed 24, 48, 72 and 120 h post-
tetrasodium salt; Calbiochem 481973, San Diego, CA, USA)
were pipetted for a total 200-lL reaction volume. After 40 min
Channel catfish (Ictalurus punctatus), rainbow trout (Oncorhyn-
of incubation at room temperature on a shaker, 200 lL of ice-
chus mykiss) and red tilapia (Oreochromis sp.) are finfish of great
cold acetonitrile were added to stop the reaction. The tubes were
importance for aquaculture in the USA and worldwide. Channel
centrifuged at 8000 g for 20 min in a refrigerated high-speed
catfish is cultured mainly in the south states in USA and is the
centrifuge (Biofuge 22R – Heraeaus Instruments, Hanau,
species with the highest revenues and production yields in the
Germany). Supernatants were stored at )80 °C until HPLC
country. Rainbow trout and tilapia are among the most cultured
metabolite analysis. Preliminary experiments were done to
and produced species around the world. Imports of tilapia in the
determine linearity of the metabolic reaction with regard to
USA have surged over 350% in the last 8 years (FAO, 2007).
incubation time and protein content.
These three species were chosen for the present study consid-ering their importance in the aquaculture activities around the
Albendazole metabolites obtained after in vitro incubation ofmicrosomal fractions were analyzed according to Shaikh et al. (2003b). The liquid chromatographic system consisted of a
Hewlett-Packard Model 1050 (Palo Alto, CA, USA) with aquaternary pump, autosampler and an Agilent series 1100
fluorescence detector (290 and 330 nm excitation and emis-
Healthy, market-size specimens (n = 6) of tilapia, channel catfish
sion wavelengths respectively). Analytical and guard columns
and rainbow trout were obtained from commercial sources. After
were 5-lm Luna C18 and ODS C18 respectively. An isocratic
capture, the fish were transported to the Aquatic Pathobiology
mobile phase consisted of acetonitrile ⁄ methanol ⁄ 0.05 M ammo-
Center at the University of Maryland (College Park, MD, USA)
nium acetate buffer (pH = 5) in a ratio of 17:8:75. This
and the Center for Veterinary Medicine at the Food and Drug
mobile phase was used for the analysis of ABZ metabolites.
Administration (USFDA) (Laurel, MD, USA) where they were
Solid reference standards (1–10 mg) of ABZ, ABZ-SO, ABZ-SO2
maintained under controlled conditions for at least 3 months
and ABZ-2-NH2SO2, were prepared to obtain a range of
prior to kill and liver harvesting. Livers were minced coarsely
calibration standards according to the level of quantification.
with scissors and rinsed with KCl. After discarding the last KCl
Quantification of ABZ-SO from the in vitro incubation medium
rinsing, four volumes of ice-cold 0.25 M sucrose (ICN Biomed-
was performed based on calibration curves obtained with
icals – 821271, Costa Mesa, CA, USA) were added (e.g. 1 g
liver = 4 mL 0.25 M sucrose). The minced livers in sucrose weretransferred to a homogenizer and then to an ice-cold, high-speed
Calculation of ABZ sulfoxidation kinetics parameters
centrifuge tube and spun at 8000 g for 20 min at 4 °C (Biofuge22 R – Heraeus Instruments, Hanau, Germany). The superna-
Maximal velocity (Vmax), Michaelis–Menten constant (Km) and
tant was spun at 100 000 g for 60 min at 4 °C (Beckman
Vmax ⁄ Km were calculated by linear regression after obtaining
Ultracentrifuge XL-80, Fullerton, CA, USA).
double-reciprocal, Lineweaver–Burk plots.
Microsomal and cytosolic fractions preparation
After ultracentrifugation, the tubes were removed to ice and the
The EROD assay was conducted, with modification, according to
supernatant (cytosolic fraction) was aliquoted into cryotubes.
Eggens and Galgani (1992) and Haasch et al. (1994). Reaction
Ó 2009 Blackwell Publishing Ltd. No claim to original US government works
In vitro kinetics of hepatic albendazole sulfoxidation in three fish species
mixtures consisted of 50 lL of Tris–HCl buffer (100 mM,
mixture). Other metabolites such as ABZ-SO2 and ABZ-2-
pH = 7.4), 25 lL of microsomal fraction accounting for
NH2SO2 that have been reported in residue depletion studies
100 lg of protein, 10 lL of 7-ethoyxresorufin (7-ER) (Sigma-
with fish were not detected (Shaikh et al., 2003b). Michaelis–
E3763) (1 lM final concentration) and 25 lL of NADPH (1 mM
tetrasodium salt, Calbiochem 481973, San Diego, CA, USA).
reaction kinetics for each species are shown in Fig. 1.
Blanks consisted of reaction mixtures with boiled microsomes.
Apparent maximum velocity (Vmax), Michaelis–Menten con-
Reaction was quantified by reading the fluorescence units of
stant (Km) and Vmax ⁄ Km values for this reaction are presented
in Table 1. Channel catfish had higher Vmax (264.0 ± 58.6
microplate absorbance–fluorescence reader (GeniosÔ – TECAN,
pmols ABZ-SO ⁄ min ⁄ mg protein) as compared with tilapia
Austria). A resorufin calibration curve (0–0.5 lM) was used for
(112.3 ± 8.2) and rainbow trout (73.3 ± 10.3). Km values
the quantification of the reaction rate.
(lM) varied significantly (P < 0.05) among the species: rain-
Pentoxyresorufin- (PROD) and benzyloxyresorufin-o-dealkyla-
bow trout (3.9 ± 0.5), tilapia (9.2 ± 1.7) and catfish (22.0 ±
tion (BROD) activities. PROD and BROD activities were assayed
3.2). These results indicate that rainbow trout had the highest
following the same protocol as for EROD. A 5 lM substrate
binding affinity for the substrate. Statistical analysis of the
concentration was tested. Phenobarbital-induced rat microsomes
Vmax ⁄ Km ratios showed no difference among the three species:
(R1078 – Xenotech, LLC, St Lenexa, KS, USA) served as positive
catfish (12.3 ± 1.9), tilapia (13.6 ± 1.7) and rainbow trout
Glutathione-s-transferase activity was determined by the
method of Habig et al. (1974). Reaction mixtures consisted of165 lL of 100 mM Tris–HCl buffer (pH = 7.4), 7 lL of 1-chloro-2,4-dinitrobenzene (CDNB; Sigma C 6396) (1 mM final concen-
tration), 3.5 lL of 60 mM reduced L-glutathione (Sigma G 6529)
and 10 lg of cytosolic protein. Blanks consisted of reactionmixtures with exception of the cytosolic fraction. The rate of
CDNB conjugation with GSH was evaluated after 5 min ofreaction determining changes in absorbance (k = 340 nm) at
room temperature. Absorbance readings were obtained using a
molar absorption coefficient for CDNB (€ = 9.6 ⁄ m
used for final calculations after adjusting the path length to thecorresponding 96-well plate volume (Styrene microtiterÒ S25-
[ABZ] µM
Results from albendazole in vitro metabolism and phase I–IIbiotransformation
(Shapiro–Wilcoxon test) and homogeneity of variances (Bar-
lettt’s test). Log transformations were calculated for somevariables to comply with statistical assumptions. Data being
both normal and homogeneous were compared using a one-way ANOVA test (comparison among species) followed by
Tukey’s mean separation test using SAS (Statistical AnalysisSoftware, Cary, NC, USA). Statistical significance was set at a
1/velocity 1/[ABZ] µM
Albendazole was transformed by hepatic microsomes to a
Fig. 1. (a) Michaelis–Menten plot of albendazole (ABZ) sulfoxidation by
single metabolite, ABZ sulfoxide (ABZ-SO) in the three species.
rainbow trout (RBT), tilapia (TILA) and channel catfish (CC) hepatic
This ABZ sulfoxidation reaction was NADPH-dependent as no
microsomes (n = 6) (means ± SEM). Velocity expressed in pmols ABZ-
ABZ-SO was detected in controls (no NADPH in incubation
SO ⁄ min ⁄ mg protein. (b) Lineweaver–Burk (double-reciprocal) plot.
Ó 2009 Blackwell Publishing Ltd. No claim to original US government works
Table 1. Vmax, Km and Vmax ⁄ Km values for in vitro ABZ sulfoxidation of
catfish, tilapia and trout hepatic microsomes (means ± SEM) (different
letters in the same column denote significant differences among the
EROD activity Time after ABZ dosage
Fig. 2. Ethoxyresorufin-o-deethylation activity (pmols resoru-fin ⁄ min ⁄ mg protein) of hepatic microsomes from albendazole-dosedchannel catfish (n = 6) (means ± SEM). Different letters on bars denote
Changes in EROD, PROD, BROD and GST activities after ABZ
statistically significant difference (P < 0.05).
A significant induction (2.2–2.6-fold) on EROD activity was
found in all the ABZ-dosed time points compared with controls
(Rawden et al., 2000) in other studies. Shaikh et al. (2003b)
(Fig. 2). Neither control fish nor ABZ-dosed fish showed PROD
found in residue depletion studies that rainbow trout and
or BROD activities in the microsomal fraction. No induction of
tilapia depleted ABZ in muscle by 12 h after ABZ ingestion,
GST activity was found in either of the ABZ treatments as
whereas channel catfish did it after 8 h (Shaikh et al., 2006).
compared with control values. Interestingly, GST activity was
Interestingly, we found in the present study that channel
lower in the 120-h treatment when compared with control
catfish had the highest ABZ sulfoxidation rate of all three
species which correlates with the shortest depletion time forABZ in muscle found by Shaikh et al. (2003b). ABZ-SOdepletion in channel catfish was also the shortest (8 h) as
compared with the ones found in tilapia (48 h) and rainbowtrout (48 h). Shaikh et al. (2003b) found the longest retention
time in muscle for ABZ (24 h) an ABZ-SO (96 h) in Atlantic
The present study compared hepatic in vitro ABZ sulfoxidation in
salmon. Although we did not include this species in the
rainbow trout, tilapia and channel catfish. In vivo, ABZ
present study, a low in vitro ABZ sulfoxidation rate should be
undergoes negligible phase II-type of biotransformation reactions
expected if the same correlation found in the other three
and there is no sequential conjugation after the phase I
oxidation. As a result, microsomes are considered a good model
Km for ABZ sulfoxidation in channel catfish indicates that this
for ABZ in vitro metabolism (Wrighton et al., 1995). In the
species had the lowest binding affinity (e.g., highest Km value) of
present work, the microsomal fractions of all three species
the three species. Tilapia and rainbow trout showed greater
transformed ABZ to ABZ-SO. No other metabolites, such as ABZ-
binding affinities for ABZ. The three fish species studied in the
SO2 or ABZ-2-NH2SO2, that are reported in residue depletion
present work had higher binding affinities than those reported
studies in fish (Shaikh et al., 2003b), were detectable. The
for rat (53.6 lM) (Fargetton et al., 1986) and pig microsomes
absence of inactive metabolites could be due to limited oxidation
(41.7 lM) (Souhaili-ElAmry et al., 1987). Km in rainbow trout
of ABZ-SO to ABZ-SO2 in the liver or notably faster metabolism of
was even lower, although quite similar to the value reported by
ABZ to ABZ-SO not allowing the detection of the sulfone or the
Rawden et al. (2000) in human microsomes (4.6 ± 0.8). Fish
aminosulfone during the incubation period tested. Higher rates
with high biotransformation capacity may cope with extreme
of secondary sulfoxidations may occur in other organs (e.g.,
exposure concentrations better than those with low maximal
kidney) that were not evaluated in the present study. Neverthe-
velocities (Gallagher et al., 2000). However, for the purpose of
less, these data are consistent with previous studies in other
drug metabolism, the concentrations that more likely are present
animal species. When microsomal fractions of sheep (Galtier
at the site of biotransformation are in a lower range than the Km
et al., 1986), rat (Fargetton et al., 1986), pig (Souhaili-ElAmry
et al., 1987) and human (Rawden et al., 2000), were incubated
Vmax ⁄ Km is a pure measure of enzyme activity and is not
with ABZ as the parent compound, ABZ-SO was the only
influenced by other physiological factors of liver clearance.
This parameter is used as the basis for the extrapolation of
Channel catfish had the highest Vmax for the ABZ sulfox-
in vitro data to the in vivo situation (Houston, 1994).
idation of all three species. Vmax values in the fish species
Estimation of in vivo drug clearance is based on application
studied in this work were lower than those obtained for rat
of models that account for nonenzymatic, physiological factors
(590 pmols ⁄ min ⁄ mg protein) (Fargetton et al., 1986), pig
as well as the Vmax ⁄ Km estimate. When Vmax and Km values
(580 pmols ⁄ min ⁄ mg protein) (Souhaili-ElAmry et al., 1987)
were combined in the present work to analyze the overall
Ó 2009 Blackwell Publishing Ltd. No claim to original US government works
In vitro kinetics of hepatic albendazole sulfoxidation in three fish species
enzyme efficiency of the sulfoxidation process, the three species
The expression at the transcriptional level of the CYP1A gene
had very similar results. The high Vmax value found in catfish
is mediated through a ligand-dependent transcription factor
was accompanied by a high Km (e.g., low binding affinity),
located in the cytoplasm and known as the AhR receptor. Some
whereas an inverse relationship occurred in rainbow trout
of the organic contaminants previously mentioned (PAHs, PCBs,
(low capacity along with low Km – high affinity). Tilapia
TCDD, etc) are recognized as AhR ligands. TCDD is the most
results were in between the ranges found for catfish and trout.
potent known AhR ligand. However, endogenous substrates
The enzyme efficiency estimate (Vmax ⁄ Km) showed that the
such as bilirubin and biliverdin have also been described as AhR
three species had quite similar capabilities to activate ABZ
ligands. Authors in this area suggest that AhR acts ‘promiscu-
ously’ as a transcription factor given that it modulates theexpression of a battery of genes in addition to the CYP1A gene(Whitlock, 1999). This non-discriminatory feature of AhR could
Alkoxyresorufins and GST induction after ABZ treatment in channel
be suggested as an explanation for the inducing effects of ABZ in
the EROD activity found in the present work.
We were interested in investigating whether or not ABZ could
induce CYP1A and GST activities in fish after a therapeutic
have been used, among other alkoxyresorufins, to characterize
regime (single dose of 10 mg ⁄ K p.o.). Other cytochrome P450-
responses of cytochrome P450 isoforms in mammals (Burke
mediated reactions (e.g., PROD and BROD), for which no isoforms
et al., 1985) and fish (Haasch et al., 1994). Induction of S9
responsible for their biotransformation have been identified in
fraction activity, specifically EROD, MROD, PROD and BROD
fish, were also investigated. Because of logistics, this part of the
activities and protein concentration of rat livers after intraperi-
study was done only with channel catfish. All of the time points
toneal ABZ injection were reported by Escobar-Garcı´a et al.
after the ABZ dosage (24, 48, 72 and 120 h) showed significant
(2001). However, neither PROD nor BROD activities were
induction of EROD activity, a good indicator of CYP1A expression
detected in either controls nor ABZ-dosed fish in the present
(Whitlock, 1999). EROD activity at all of the exposure time points
work. PROD and BROD induction has been reported in rainbow
was significantly different (P < 0.05) from the one found in the
trout after intraperitoneal injection of inducing agents such as
control (ABZ-free feed). EROD activity has been used as a good
isosafrole and dexamethasone (Haasch et al., 1994), but the
indicator of CYP1A induction in fish (Whyte et al., 2000) and
P450 isoforms involved in such biotransformation reactions
other species (Whitlock, 1999). Some of the CYP1A inducers are
have not been identified in fish. In the same study by Haasch
organic contaminants that may be present in the water column,
et al. (1994), non-induced rainbow trout had negligible baseline
in sediments or in the food. Among these compounds are
PROD ⁄ BROD activities. Although PROD ⁄ BROD inductions were
polyaromatic hydrocarbons (PAHs), coplanar polychlorinated
reported in rats after ABZ treatment, it is not uncommon to find
biphenils (PCBs), polychlorinated dibenzo-p-dioxins (TCDD),
discrepancies between inducers and the target P450 isoforms
dibenzofurans (PCDD ⁄ PCDF) and other halogenated compounds
when different animal species are compared. This makes the
present in some pesticides and herbicides. For this reason, the
extrapolation of results between species difficult.
induction of CYP1A1 protein has been widely used as a
Glutathione-s-transferase activity was significantly induced in
biomarker of pollution in many different species. EROD activity
mouse serum and muscle after ABZ treatment (Derda et al.,
induction due to in vivo ABZ treatment in a fish species had not
2003). In the present work, we found that GST did not change in
been previously reported. In the present work, ABZ exposure
24, 48 and 72 h after ABZ dosage treatments, when compared
evoked higher EROD activity in dosed-catfish (between 2.2- and
with controls. On the contrary, GST activity in the 120-h
2.6-fold) than in controls. Haasch et al. (1994) found 66.3- and
treatment was significantly lower than the one found in the
38.8-fold induction in EROD activity after rainbow trout were
control group. We have no clear explanation for this particular
treated with isosafrole and b-naphtoflavone respectively. TCDD is
reduction in GST activity in this group.
reported to induce EROD activity up to 200-fold in some fishspecies (Whyte et al., 2000). The induction found in our studywas seen in all the time point treatments. Reports on EROD
induction within the first 48 h after treatment with inducers arefound in the literature. The extent of the EROD induction may
The in vitro incubation system used in this study provided a good
depend on how easily the inducer is metabolized. PAHs, as an
indicator of the rate of ABZ sulfoxidation but not the production
example of easily metabolized inducers, elicited increases in EROD
of the sulfone or aminosulfone. There were significant differences
activity in sea bass (Dicentrarchus labrax) after 24 h, followed by
in Vmax and Km in ABZ sulfoxidation kinetics among tilapia,
dramatic decline after 1 week (Lemaire et al., 1992). Effects due
channel catfish and rainbow trout. Interestingly, Vmax values in
to halogenated inducers (e.g., TCDD) are reported to persist for
the three species correlate with muscle residue depletion times
several weeks in fish (Whyte et al., 2000). Although our exposure
found in other reports. Vmax ⁄ Km ratios showed no differences
protocol only covered 120 h, and the response was more typical
among the three species investigated. Albendazole appears to be
of an easily metabolized compound, it is worth considering likely
a weak inducer of EROD activity in channel catfish when
implications of the EROD inducing effect in ABZ-treated fish in the
compared with the effect exerted by organic pollutants as cited in
Ó 2009 Blackwell Publishing Ltd. No claim to original US government works
Further research in ABZ metabolism in fish should be directed
Eggens, M.L. & Galgani, F. (1992) Ethoxyresorufin-o-deethylase (EROD)
to discern isoforms involved in the biotransformation pathways
activity in flatfish: fast determination with a fluoresecence plate reader.
as well as the identification of the role that other organs, such as
Marine Environmental Research, 33, 213–221.
Escobar-Garcı´a, D., Camacho-Carranza, R., Pe´rez, I., Dorado, V., Arriaga-
the intestine may play in ABZ first pass metabolism.
Alba, M. & Espinosa-Aguirre, J.J. (2001) S9 induction by the combinedtreatment with cyclohexanol and albendazole. Mutagenesis, 16, 523–528.
FAO (Food and Agriculture Organization of the United Nations) (2007)
State of World Fisheries & Aquaculture 2006. FAO, Rome.
This work was funded by the Joint Institute of Food Safety and
Fargetton, X., Galtier, P. & Delatour, P. (1986) Sulfoxidation of alben-
Nutrition (JIFSAN) – Contract # FDU001418. The authors thank
dazole by a cytochrome P450-independent monooxygenase from ratliver microsomes. Veterinary Research Communications, 10, 317–324.
Charlie Gieseker and Stanley Serfling for their help with the
Gallagher, E.P., Sheehy, K.M., Lame, M.W. & Segall, H.J. (2000) In vitro
acclimation of fish specimens and Nathan Rummel for HPLC
kinetics of hepatic glutathione-s-transferase conjugation in large-
analysis at the Center for Veterinary Medicine at FDA (Laurel,
mouth bass and brown bullheads. Environmental Toxicology and
Galtier, P., Alvinerie, M. & Delatour, P. (1986) In vitro sulfoxidation of
albendazole by ovine liver microsomes: assay and frequency of various
xenobiotics. American Journal of Veterinary Research, 47, 447–452.
Gottschall, D.W., Theodorides, V.J. & Wang, R. (1990) The metabolism of
benzimidazole anthelmintics. Parasitology Today, 6, 115–124.
Asteinza, J., Camacho-Carranza, R., Reyes-Reyes, R.E., Dorado-Gonza´lez,
Haasch, M.L., Graf, W.K., Quardokus, E.M., Mayer, R.T. & Lech, J.J.
V. & Espinosa-Aguirre, J.J. (2000) Induction of cytochrome P450
(1994) Use of 7-alkoxyphenoxazones, 7-alkyloxycoumarins and
enzymes by albendazole treatment in the rat. Environmental Toxicology,
7-alkoxyquinolines as fluorescent substrates for rainbow trout hepatic
microsomes after treatment with various inducers. Biochemical Phar-
Baliharova´, V., Velı´k, J., Lamka, J., Balarinova´, R. & Ska´lova´, L. (2003)
The effects of albendazole and its metabolites on hepatic cytochromes
Habig, W.H., Pabst, M.J. & Jakoby, W.B. (1974) Glutathione S-transfer-
P450 activities in mouflon and rat. Research in Veterinary Science, 75,
ases: the first enzymatic step in mercapturic acid formation. Journal of
Biological Chemistry, 249, 7130–7139.
Burke, M.D., Thompson, S., Elcombe, C.R., Halpert, J., Haaparanta, T. &
Houston, J.B. (1994) Utility of in vitro drug metabolism data in predicting
Mayer, R.T. (1985) Ethoxy-, pentoxy- and benzyloxyphenoxazones
in vivo metabolic clearance. Biochemical Pharmacology, 47, 1469–1479.
and homologues: a series of substrates to distinguish between different
Lanusse, C.E. & Prichard, R.K. (1992) Effects of methimazole on the
induced cytochormes P-450. Biochemical Pharmacology, 34, 3337–
kinetics of netobimin metabolites in cattle. Xenobiotica, 22, 115–
Campbell, W.C. (1990) Benzimidazoles: veterinary uses. Parasitology
Lemaire, P., Mathieu, A., Giudicelli, J. & Lafaurie, L. (1992) Effect of
benzo[a]pyrene on hepatic biotransformation activities: time course of
Chiap, P., Evrard, B., Bimazubute, M.A., de Tullio, P., Hubert, P.,
induction in aquaculture European sea bass (Dicentrarchus labrax).
Delattre, L. & Crommen, J. (2000) Determination of albendazole and its
Polycyclic Aromatic Compound, 2, 263–273.
metabolites in ovine plasma by liquid chromatography with dialysis as
Li, T., Quiao, G.L., Hu, G.Z., Meng, F.D., Qui, Y.S., Zhang, X.Y., Guo,
an integrated sample preparation technique. Journal of Chromatogra-
W.X., Yie, H.L., Li, S.F. & Li, S.Y. (1995) Comparative plasma and
tissue pharmacokinetics and drug residue profiles of different chemo-
Cook, G.C. (1990) Use of benzimidazole chemotherapy in human
therapeutants in fowls and rabbits. Journal of Veterinary Pharmacology
Moroni, P., Buronfosse, T., Longin-Sauvageon, C., Delatour, P. & Benoit,
Cristo`fol, C., Navarro, M., Franquelo, C., Valladares, J. & Arboix, M.
E. (1995) Chiral sulfoxidation of albendazole by the flavin adenine
(1998) Sex differences in the disposition of albendazole metabolites in
dinucleotide-containing and cytochrome P450-dependent monooxy-
sheep. Veterinary Parasitology, 78, 223–231.
genases from rat liver microsomes. Drug Metabolism and Disposition, 23,
Csiko, G.Y., Bandidi, G.Y., Semjen, G., Laczay, P., Sandor, G.V., Lehel, J. &
Fekete, J. (1996) Metabolism and pharmacokinetics of albendazole
Ottesen, E.A., Ismail, M.M. & Horton, J. (1999) The role of albendazole in
after oral administration to chickens. Journal of Veterinary Pharmacol-
programmes to eliminate lymphatic filariasis. Parasitology Today, 15,
ogy and Therapeutics, 19, 322–325.
Delatour, P., Benoit, E., Besse, S. & Boukraa, A. (1991a) Comparative
Rawden, H.C., Kokwaro, G.O., Ward, S.A. & Edwards, G. (2000) Relative
enantioselectivity in the sulphoxidation of albendazole in man, dogs,
contribution of cytochromes P-450 and flavin-containing monooxy-
and rats. Xenobiotica, 21, 217–221.
genases to the metabolism of albendazole by human liver microsomes.
Delatour, P., Garnier, F., Benoit, E. & Caude, I. (1991b) Chiral behaviour
British Journal of Clinical Pharmacology, 49, 313–322.
of the metabolite albendazole sulfoxide in sheep, goats and cattle.
Rolin, S., Souhaili-ElAmry, H., Batt, A.M., Levy, M., Bagrel, D. & Siest, G.
Research in Veterinary Science, 50, 134–138.
(1989) Study of the in vitro bioactivation of albendazole in human liver
Derda, M., Boczon, K., Wandurska-Nowak, E. & Wojt, W. (2003)
microsomes and hepatoma cell lines. Cell Biology and Toxicology, 5, 1–14.
Changes in the activity of glutathione-s-transferase in muscles and
Schmahl, G. & Benini, J. (1998) Treatment of fish parasites. 11. Effects of
sera from mice infected with Trichinella spiralis after treatment with
albendazole and levamisole. Parasitology Research, 89, 509–512.
fenbendazole) on Glugea anomala, Moniez, 1887 (Microsporidia):
Douch, P.G. & Buchanan, L.L. (1979) Some properties of the sulphox-
ultrastructural aspects and efficacy studies. Parasitology Research, 60,
idases and sulphoxide reductases of the cestode Moniezia expansa, the
nematode Ascaris suum and mouse liver. Xenobiotica, 9, 675–679.
Ó 2009 Blackwell Publishing Ltd. No claim to original US government works
In vitro kinetics of hepatic albendazole sulfoxidation in three fish species
Shaikh, B., Rummel, N., Gieseker, C., Serfling, S. & Reimschuessel, R.
P450 dependent mono-oxygenases from pig liver microsomes.
(2003a) Metabolism and residue depletion of albendazole and its
metabolites in rainbow trout, tilapia and Atlantic salmon after oral
Souhaili-ElAmry, H., Fargetton, X., Benoit, E., Totis, M. & Batt, A.M.
administration. Journal of Veterinary Pharmacology and Therapeutics, 26,
(1988) Inducing effect of albendazole on rat liver drug-metabolizing
enzymes and metabolite pharmacokinetics. Toxicology and Applied
Shaikh, B., Rummel, N. & Reimschuessel, R. (2003b) Determination of
albendazole and its major metabolites in the muscle tissues of Atlantic
Vodicnik, M.J., Elcombe, C.R. & Lech, J.J. (1981) The effect of various
salmon, tilapia and rainbow trout by high performance liquid chro-
types of inducing agents on hepatic microsomal monooxygenase
matography with fluorometric detection. Journal of Agricultural and
activity in rainbow trout. Toxicology and Applied Pharmacology, 59,
Shaikh, B., Rummel, N., Geiseker, C. & Reimschuessel, R. (2006)
Whitlock, J.P. Jr (1999) Induction of cytochrome P4501A1. Annual
Metabolism and depletion of albendazole in the muscle tissue of
Review of Pharmacology and Toxicology, 39, 103–125.
channel catfish following oral treatment. Journal of Veterinary Phar-
Whyte, J.J., Jung, R.E., Schmitt, C.J. & Tillitt, D.E. (2000) Ethoxyresoru-
macology and Therapeutics, 51, 3254–3259.
fin-O-deethylase (EROD) activity in fish as a biomarker of chemical
Solana, H.D., Rodrı´guez, J.A. & Lanusse, C.E. (2001) Comparative
exposure. Critical Reviews in Toxicology, 30, 347–570.
metabolism of albendazole and albendazole sulphoxide by different
Wrighton, S.A., Ring, B.J. & VandenBraden, M. (1995) The use of in vitro
helminth parasites. Parasitology Research, 87, 275–280.
metabolism techniques in the planning and interpretation of drug
Souhaili-ElAmry, H., Fargetton, X., Delatour, P. & Batt, A.M. (1987)
safety studies. Toxicologic Pathology, 23, 199–208.
Sulphoxidation of albendazole by the FAD-containing and cytochrome
Ó 2009 Blackwell Publishing Ltd. No claim to original US government works
What You Need to Know about Doxycycline for Prevention of Anthrax You are being given a medicine called doxycycline (sounds like DOCKS-ee-SY-cleen) because you may have breathed in anthrax germs. These germs can be deadly. Taking this drug reduces your chance of getting sick and dying. Until officials know for sure who breathed in the germs, it is important to start taking this
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