Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 87
Pesticide Resistance: Strategies and Tactics for Management.
1986. National Academy Press, Washington, D.C.
Resistance to 4-Hydroxycoumann
Anticoagulants in Rodents
ALAN D. MACNICOLL
There are few reported cases of development of resistance to
pesticides in vertebrates. The most widespread and well-documented
example is resistance to warfarin in rodents. It has been demon-
strated in Rattus norvegicus and Mus musculus that inheritance of
warfarin resistance is monogenic and the gene is closely linked to
that for coat color. The biochemistry and mechanism of resistance
in the latter species has not been investigated thoroughly, but war-
farin resistance may be associated with an altered metabolism of the
anticoagulant. Wa~arin resistance in R. norvegicus is probably as-
sociated with alterations in a vitamin K metabolizing enzyme or
enzymes. Second-generation anticoagulants, which are more toxic
than warfarin, were introduced in the 1970s and were considered
elective in controlling warfarin-resistant rodent infestations. Some
warfarin-resistant populations may also be cross-resistant to other
4-hydroxycoumarin anticoagulant rodenticides, and control of these
infestations with more toxic compounds is less effective than using
warfarin to control anticoagulant-susceptible rodents.
INTRODUCTION
The incidence of inheritable resistance to pesticides in vertebrates is re-
markably low. The mosquito fish Gambusia Alibis (Vinson et al., 1963;
Boyd and Ferguson, 1964) and other fish species (Ferguson et al., 1964;
Ferguson and gingham, 1966) have developed resistance to chlorinated hy-
drocarbon pesticides. Also, two frog species may have developed resistance
to DDT (Boyd et al., 19631. Incidences of inheritable pesticide resistance in
87
OCR for page 88
88
MECHANISMS OF RESISTANCE TO PESTICIDES
mammals are confined almost exclusively to rodents. Differential suscepti-
bility to fluoroacetate, however, has been reported in some areas of Australia
in populations of the grey kangaroo and tammar wallaby, as well as the bush
rat Rattus fuscipes (Oliver et al., 19791. Inheritable tolerance in these species
is thought to be a result of the abundance in some parts of Australia of
leguminous plants that naturally produce fluoroacetate.
Genetically determined resistance in humans to coumarin anticoagulant
drugs, some of which are also used as rodenticides, was first reported in
1964 (O' Reilly et al., 1964~. Resistance to coumarin anticoagulants in rodents
is the most widespread and thoroughly investigated example of inheritable
pesticide resistance in vertebrates and will be discussed in detail.
A laboratory mouse strain has been developed that showed a 1.7-fold
tolerance to DDT when compared to the original susceptible strain (Ozburn
and Morrison, 19621. This was achieved by treating nine successive gen-
erations with DDT and breeding the survivors. Probably more significant
was the discovery that pine voles, Microtus pinetorium, trapped in orchards
with a history of endrin treatment, had a 12-fold resistance to this compound,
compared with voles trapped in untreated orchards (Webb and Horsfall,
19671. These resistant animals also showed a two-fold cross-resistance to
dieldrin, a stereoisomer of endrin. This example of inheritable resistance
may be associated with alterations in the metabolism of endrin, as indicated
by studies on the hepatic, microsomal, mixed-function oxidase system of
endrin-resistant and endrin-susceptible strains (Webb et al., 1972; Hartgrove
and Webb, 19731.
INCIDENCE AND GENETICS OF WARFARIN
RESISTANCE IN RODENTS
Warfarin resistance in R. norvegicus was first noted in Scotland in 1958
(Boyle, 1960) and subsequently on the Wales-England border (Drummond
and Bentley, 1967) and in Denmark (Lund, 1964), Holland (Ophof and
Langveld, 1969), Germany (Telle, 1967), and the United States (Jackson
and Kaukeinen, 19721. These initial observations were not isolated, and in
1979, it was reported in 36 out of 77 American cities surveyed that more
than 10 percent of each R. norvegicus population was warfarin-resistant
(Jackson and Ashton, 19801. With evolutionary pressure from the continued
use of warfarin, some resistant populations can spread to cover areas of
several thousand square kilometers (Greaves, 19701.
Inheritance of warfarin resistance in R. norvegicus is due to the inheritance
of an autosomal gene, closely linked to the gene controlling coat color, which
has been mapped in linkage group I (Greaves and Ayres, 19694. Further
genetic studies (Greaves and Ayres, 1977, 1982) on warfarin resistance in
wild rats from Wales, Scotland, and Denmark showed that there are at least
OCR for page 89
RESISTANCE TO 4-HYDROXYCOUMARIN ANTICOAGULANTS
89
three multiple alleles of the warfarin resistance gene Rw. Strains of R. norv-
egicus derived from wild Welsh or Danish rats have an increased requirement
for vitamin K (Pool et al., 1968; Hermodson et al., 1969; Greaves and Ayres,
1973, 1977; Martin, 1973), but only the Welsh resistance gene is described
as dominant (Greaves and Ayres, 1969, 19821.
Inheritable warfarin resistance in Rattus rattus has been observed in the
United Kingdom (Greaves et al., 1973a, 1976), Australia (Saunders, 1978),
and the United States (Jackson and Ashton, 1980~. Warfarin resistance in
this species was a significant problem in 4 of 12 American cities where
populations had been sampled.
Warfarin resistance in the house mouse Mus musculus has followed a
similar pattern to that of R. norvegicus. Problems in controlling house mice
(Dodsworth, 1961) were initially thought to be due to inheritance of more
than one gene (Rowe and Redfern, 1965; Roll, 19661. Subsequent investi-
gations (Wallace and MacSwiney, 1976) demonstrated a major warfarin
resistance gene, War, that was closely linked to coat color and located on
chromosome 7 in the mouse, which is analogous to linkage group I in the
rat. Monitoring of warfarin resistance in the house mouse is not routine, but
resistance seems to be widespread (Jackson and Ashton, 19801.
WARFARIN ACTION AND RESISTANCE MECHANISM
The naturally occurring anticoagulant dicoumarol (structure I in Figure 2)
was isolated from moldy sweet clover hay in 1939 (Link, 19441. Following
observations that cattle that were fed on spoiled sweet clover hay developed
a fatal haemorrhagic malady, dicoumarol was subsequently clinically used
as a prophylactic agent against thrombosis. Oral vitamin K3 (menadione:
structure V in Figure 2) or vitamin Kit were antidotal in excessive hypo-
prothrombinaemia (Cromer and Barker, 1944; Lehmann, 19431. This natu-
rally occurring coumarin was also considered for rodent control, but it was
replaced by a more toxic synthetic analogue, warfarin (structure II in Figure
21. Warfarin was also more suitable than dicoumarol for routine clinical use
and for 30 years has been widely used both as a drug and as a rodenticide
(Shapiro, 1953; Clatanoff et al., 19541.
Despite this widespread dual use of warfarin and the known role of vitamin
K as an antidote, little progress was made in elucidating the mode of action
of warfarin until the mid-1970s. Vitamin K and warfarin are antagonistic in
their effects on the synthesis of blood-clotting factors II, VII, IX, and X. In
1974 y-carboxyglutamic acid residues (GLA) were discovered (Stenflo et
al., 1974) in prothrombin (factor II), which were not present in the altered
proteins in the blood of cows or humans treated with coumarin anticoagulants.
Post-translational ~y-carboxylation of glutamyl residues appears to require the
hydroquinone (or reduced form) of vitamin K as a cofactor (Sadowski et al.,
OCR for page 90
go
MECHANISMS OF RESISTANCE TO PESTICIDES
Glutamic
acid
\
y-Carboxy
ghutanic acid
OH \ O2 + CO2 / o
FIR Carboxylase
OH ~NAD(P)+
~\ O ~ ~
_ NAD(P)H
~3
/.. 0~
11
Ha
11
o
FIGURE 1 Schematic representation of the vitamin K cycle.
1980), and vitamin K 2,3-epoxide is a product of this reaction (Larson et
al., 198 1 ). An enzyme cycle (Figure 1 ~ exists in liver microsomes to generate
vitamin K hydroquinone from the epoxide, with the quinone form of the
vitamin as an intermediate product (Fasco and Principe, 1980; Fasco et al.,
19821. Administration of warfarin and vitamin Kit to rats increased the ratio
of vitamin Kit 2,3-epoxide to vitamin Kit quinone in plasma and liver, when
compared with animals that received vitamin Kit alone (Bell and Caldwell,
1973~. This effect was more pronounced in warfarin-susceptible than in
warfarin-resistant animals. Further studies confirmed the hypothesis that 4-
hydroxycoumarin anticoagulants act by inhibiting the enzyme vitamin K
epoxide reductase (Ren et al., 1974, 1977; Shearer et al., 19741. In addition,
Sf-)-warfarin was more effective in inhibiting prothrombin synthesis and
vitamin K epoxide reductase activity than the Rt + )-enantiomer (Bell and
Ren, 1981~. An efficient method for determining the warfarin resistance
genotype in R. norvegicus was based partly on the effect of coadministration
of vitamin Kit 2,3-epoxide and warfarin on prothrombin synthesis (Martin
et al., 1 9791. Analysis of blood-clotting time 24 hours after treatment showed
that rats that were either homozygous or heterozygous for the Welsh warfarin
resistance gene had normal prothrombin levels, but homozygous-susceptible
animals had elongated clotting times. The implication was that warfarin-
resistant animals were able to utilize vitamin K 2,3-epoxide in the presence
OCR for page 91
RESISTANCE TO 4-HYDROXYCOUMARIN ANTICOAGULANTS
91
of warfarin. Other studies showed that warfarin metabolism and excretion
were not significantly altered in warfarin-resistant strains of R. norvegicus
when compared with a related susceptible strain (Hermodson et al., 1969;
Townsend et al., 19751.
This evidence, and some from other studies not described above, led to
the common belief that 4-hydroxycoumarin anticoagulants inhibit the enzyme
vitamin K epoxide reductase, which is altered in warfarin-resistant rats (R.
norvegicus), and therefore indirectly inhibits the synthesis of vitamin K-
dependent clotting factors. These hypotheses can be questioned on a number
of points. All of the supporting evidence has been obtained from investi-
gations of the metabolism of vitamin Kit (phylloquinone) and its epoxide,
but this form of vitamin K is present only in plant material (McKee et al.,
1939~. Vertebrates (Dialameh et al., 1971) as well as invertebrates (Burt et
al., 1977) and bacteria (Tishler and Sampson, 1948), synthesize compounds
of the vitamin K2 (menaquinone) series. Compounds of the vitamin K2 series
have a variable-length polyisoprene (unsaturated) substituent at the 3-position
of the 2-methyl 1,4-naphthoquinone nucleus, whereas the side chain of phyl-
loquinone is 20 carbon atoms long and has only one double bond. Synthesis
of vitamin K2~20', the equivalent of phylloquinone, by chick liver microsomes
is inhibited by warfarin in vitro (Dialameh, 1978), and the effects of the
Sk - ~ and Rid + )-enantiomers are proportional to the effects on prothrombin
synthesis. In addition, menadione (vitamin K3) is as effective as phylloqui-
none (when administered intravenously) in relieving vitamin K deficiency in
chicks (Dam and Sondergaard, 1953), but it is not as effective an antidote
to warfarin (Green, 1966; Griminger, 1966~.
Studies on vitamin K metabolism in warfarin-resistant R. norvegicus until
recently have only been carried out using animals derived from wild Welsh
rats (Pool et al., 1968; Greaves and Ayres, 19691. These rat strains un-
doubtedly have an altered hepatic microsomal vitamin K epoxide reductase
with reduced sensitivity to warfarin. The activity of this enzyme is, however,
as sensitive to warfarin in a strain derived from wild Scottish warfarin-
resistant rats as the enzyme from a closely related susceptible strain (MacNicoll,
19854. Studies of warfarin inhibition in vitro of NADH and dithiothreitol-
dependent vitamin K reductase (Fasco and Principe, 1980; MacNicoll et al.,
1984) have shown that this enzyme is as sensitive to warfarin as vitamin K
epoxide reductase, but it probably is not the same enzyme. Similar inves-
tigations of the vitamin K-dependent~y-glutamyl carboxylase, however, have
shown that this third enzyme of the vitamin K cycle is relatively insensitive
to warfarin (Hildebrandt and Suttie, 1982) and is probably not inhibited
directly in vivo by 4-hydroxycoumarin anticoagulants. The hypothesis that
inhibition of vitamin K epoxide reductase is the only effect of warfarin on
vitamin K-dependent protein synthesis and that reduced warfarin sensitivity
of this enzyme is the result of expression of all of the different allelic forms
OCR for page 92
92
MECHANISMS OF RESISTANCE TO PESTICIDES
of the warfarin resistance gene in R. norvegicus is, therefore, questionable
(Bechtold et al., 1983; MacNicoll, 1985; Preusch and Sutte, 19841.
Other hypotheses on the mechanism of warfarin resistance in R. norvegicus
have been largely discounted. For example, Ernster et al. (1972) observed
that the activity of the enzyme DT-diaphorase was considerably lower in a
soluble fraction prepared from the livers of warfarin-resistant rats when com-
pared with preparations from susceptible animals. This enzyme is present
(in different forms) in several liver fractions, utilizes NADH or NADPH as
cofactors, and reduces quinone groups in a number of substrates including
menadione (vitamin K3) (Ernster et al., 1960~. DT-diaphorase is also highly
sensitive to dicoumarol, and it was concluded (Ernster et al., 1972) that
altered activity of this enzyme was a result of expression of the warfarin
resistance gene. A later study (Greaves et al., 1973b), however, clearly
demonstrated that the different enzyme activities were more correctly as-
signed to differences between the Wistar stock, from which the warfarin-
resistant animals were derived, and the Sprague-Dawley strain, which was
used for the susceptible comparison in the earlier study. This enzyme has
been implicated in the production of vitamin K hydroquinone in viva. Highly
purified rat-liver cytosolic DT-diaphorase reduced vitamin Kit (Fasco and
Principe, 1982~; this reduction was dicoumarol- but not warfarin-sensitive.
The results are inconsistent with the warfarin-sensitive NADH or DDT-
dependent vitamin K~ hydroquinone formation observed with crude rat-liver
microsomal fractions. Recent studies (Lied et al., 1982; Talcott et al., 1983)
on the action of DT-diaphorase in detoxification or activation of a wide range
of quinones, including some antimalarial drugs, suggests that the capacity
of this enzyme for vitamin K reduction is not associated with the ribosomal
synthesis of vitamin K-dependent clotting factors.
A more recent hypothesis on the mechanism of warfarin resistance in R.
norvegicus was based on the formation of 2- or 3-hydroxyvitamin K~ from
the epoxide by liver microsomal fractions (Fasco et al., 19831. These putative
metabolites were detected in greater quantities in incubations with prepara-
tions from warfarin-resistant rats when compared with preparations from
susceptible animals. This observation was associated with the reduced activity
of vitamin K epoxide reductase in that resistant strain. A second report,
however, showed that under certain conditions these hydroxylated com-
pounds were formed by a chemical reaction in control incubations (Hilde-
brandt et al., 19841. The apparent increase in metabolism to these compounds
by liver microsomes from resistant animals probably reflected the reduced
rate of metabolism to the quinone form of the vitamin. The detection of
hydroxyvitamin K~ in the blood of warfarin-resistant rats that had received
an intravenous injection of vitamin K 2,3-epoxide (Preusch and Suttie, 1984),
therefore, is probably not associated directly with expression of the warfarin
resistance gene.
OCR for page 93
RESISTANCE TO 4-HYDROXYCOUMARIN ANTICOAGULANTS
93
Little if any work has been carried out on the mechanism of warfarin
resistance in R. rattus, but there have been many studies conducted on M.
musculus. Observations of the effect of warfarin on mortality and blood
clotting in wild warfarin-resistant and -susceptible house mice indicated that
resistant animals developed a tolerance to daily doses of warfarin (admin-
istered intravenously) up to 100 mg/kg, and susceptible animals developed
a tolerance to doses of 1 mg/kg administered at 21-day intervals (Rowe and
Redfern, 19681. Female mice were particularly tolerant to warfarin. Animals
trapped in areas with control problems had normal clotting times when fed
a diet containing 0.025 percent warfarin for 21 days.
As mentioned above, warfarin resistance in M. musculus is due to inher-
itance of the gene War located on chromosome 7 (Wallace and MacSwiney,
1976~. This resistance may be related to a gene on the same chromosome
(Wood and Conney, 1974), which is expressed as an increased rate of hy-
droxylation of coumarin. Subsequent investigation of 16 different strains
demonstrated that warfarin resistance and rapid coumarin hydroxylation were
not coinherited (Lush and Arnold, 19751. Warfarin resistance in this species
may be inversely related to hexobarbitone sleeping time, but it is not stim-
ulated by phenobarbitone (Lush, 19761. The report suggested that warfarin
resistance in the house mouse may be due to an increased rate of warfarin
hydroxylation. There are no reports of vitamin K deficiency in warfarin-
resistant mouse strains, and it is possible that resistance in this species is
related to alterations in warfarin rather than vitamin K metabolism.
SECOND-GENERATION ANTICOAGULANT RODENTICIDES
The three compounds (Figure 2) based on 4-hydroxycoumarin, commonly
known as the second-generation anticoagulant rodenticides, are difenacoum
(structure III: when radical = hydrogen), brodifacoum (structure III: when
radical = bromine), and bromadiolone (structure IV). The mechanism of
action of these compounds is assumed to be the same as for warfarin. The
increased toxicity is assigned to the highly lipophilic nature of the substituents
at the 3-position of the 4-hydroxycoumarin nucleus (Hadler and Shadbolt,
1975; Dubock and Kaukeinen, 1978~. Initial laboratory studies and field
trials indicated that these compounds could effectively control warfarin-re-
sistant rat and mouse populations (Hadler, 1975; Hadler et al., 1975; Hadler
and Shadbolt, 1975; Redfern et al., 1976; Rennison and Dubock, 1978;
Redfern and Gill, 1980; Lund, 1981; Richards, 1981; Rowe et al., 19811.
Studies in vitro on the mode of action of difenacoum (Whitlon et al., 1978;
Hildebrandt and Suttie, 1982) and in vivo on difenacoum and brodifacoum
(Breckenbridge et al., 1978; Leck and Park, 1981) indicated that these com-
pounds inhibited the enzyme vitamin K epoxide reductase and were effective
in both warfarin-susceptible and -resistant R. norvegicus.
OCR for page 94
94
MECHANISMS OF RESISTANCE TO PESTICIDES
OH AH
r - ~'CH
I
OH ¢4
III OR
o
m:CH3
o
I K, Ra CH' of CH2` ACHE` iCH3
Kit R=CH' off ~H2` ACHE ACHE
CH3 CH 3
K3 R-H
OH ~ 11
[^H ~C'H EACH
II
OH ~ OH
AH C H`3`Br
V
FIGURE 2 Chemical structures: I. Dicoumarol. II. Warfare. III. When the radical (R)
is hydrogen, the compound is difenacoum. When R is bromine, the compound is bro-
difacoum. IV. Bromadiolone. V. Vitamin K.
Some early reports on field trials of difenacoum and bromadiolone ex-
pressed concern about apparent incidences of cross-resistance observed in
some warfarin-resistant populations of R. norvegicus and M. musculus. A
laboratory test for difenacoum resistance in R. norvegicus was developed a
few years after this compound was introduced as a rodenticide (Redfern and
Gill, 19781. A significant widespread incidence of difenacoum resistance
was detected in rat populations across an area of English farmland (Greaves
et al., 1982a) where a monogenic form of resistance to warfarin had been
present for several years. Resistance to difenacoum suggested that this was
an example of another allele of the warfarin resistance gene, since no dif-
ficulty had been experienced previously in controlling warfarin-resistant pop-
ulations of R. norvegicus (Rennison and Dubock, 1978~. Further field trials
OCR for page 95
RESISTANCE TO 4-HYDROXYCOUMARIN ANTICOAGULANTS
95
of bromadiolone, brodifacoum, and difenacoum in this area showed that
these compounds were not as effective in controlling the R. norvegicus
populations as warfarin was for controlling warfarin-susceptible infestations
(Greaves et al., 1982b). Continued use of 4-hydroxycoumarin anticoagulants
in this area may apply evolutionary pressure favoring animals that may be
resistant to this whole class of compounds. Since there are several forms of
the warfarin resistance gene in R. norvegicus, and inherited resistance in R.
rattus and M. musculus, it may be difficult to control rodent infestations in
other areas using 4-hydroxycoumarin anticoagulants.
CONCLUSION
The development of resistance to 4-hydroxycoumarin anticoagulants in
rodents may have implications for resistance to other pesticides. Studies on
the biochemistry and pharmacology of warfarin resistance may have provided
misleading information. Almost all such studies used rat strains derived from
wild Welsh rats, and comparative studies have not always used a suitable
susceptible control. At least one hypothesis of the mechanism of resistance
was erroneously based on a strain difference. The current theory on altered
vitamin K epoxide reductase activity may apply only to animals whose re-
sistance is associated with an increased susceptibility to vitamin K deficiency.
When the highly toxic second-generation anticoagulants were developed,
most of the evidence for the control of warfarin-resistant R. norvegicus was
based on studies using rats of the Welsh resistant strains. Control of rat
infestations in Wales and several other areas was achieved with these com-
pounds, but in other areas resistance to the new compounds developed or
was already present. It is important, therefore, that appropriate comparative
studies are carried out and that when similar compounds are introduced to
control pesticide-resistant populations, the potential for cross-resistance is
fully investigated.
There is not a logical explanation for the apparent confinement of cross-
resistance to 4-hydroxycoumarin anticoagulants to the United Kingdom. The
long history of widespread use of anticoagulants for rodent control may be
significant, but so could the established system for detecting and monitoring
rodenticide resistance, which may not be so well developed in other countries.
It is likely, therefore, that the continued use of 4-hydroxycoumarin antico-
agulants in areas with known warfarin-resistant populations could result in
rodent infestations that are difficult to control with any of this class of
compounds.
REFERENCES
Bechtold, H., D. Trenk, T. Meinertz, M. Rowland, and E. Jahnchen. 1983. Cyclic interconversions
of vitamin Kit and vitamin Kit 2,3-epoxide in man. Br. J. Clin. Pharmacol. 16:683-689.
OCR for page 96
96
MECHANISMS OF RESISTANCE TO PESTICIDES
Bell, R. G., and P. T. Caldwell. 1973. Mechanism of warfarin-resistance. Warfarin and the me-
tabolism of vitamin Kit. Biochemistry 12:1759-1762.
Bell, R. G., and P. Ren. 1981. Inhibition by warfarin enantiomers of prothrombin synthesis, protein
carboxylation, and the regeneration of vitamin K from vitamin K epoxide. Biochem. Pharmacol.
30: 1953-1958.
Boyd, C. E., and D. E. Ferguson. 1964. Susceptibility and resistance of mosquito fish to several
insecticides. J. Econ. Entomol. 57:430-431.
Boyd, C. E., S. B. Vinson, and D. E. Ferguson. 1963. Possible DDT resistance in two species of
frog. Copeia 2:426-429.
Boyle, C. M. 1960. Case of apparent resistance of Rattus norvegicus Berkenhout to anticoagulant
poisons. Nature (London) 188:517.
Breckenbridge, A. M., J. B. Leck, B. K. Park, M. J. Serlin, and A. Wilson. 1978. Mechanisms
of action of the anticoagulants warfarin, 2-chloro-3-phytylnapthoquinone (Cl-K), acenocoumarol,
brodifacoum and difenacoum in the rabbit. Br. J. Pharmacol. 64:399.
Burt, V. T., E. Bee, and J. F. Pennock. 1977. The formation of menaquinone-4 (vitamin K) and
its oxide in some marine invertebrates. Biochem. J. 162:297-302.
Clatanoff, D. V., P. O. Triggs, and O. O. Meyer. 1954. Clinical experience with coumarin anti-
coagulants Warfarin and Warfarin sodium. Arch. Int. Med. 94:213-220.
Cromer, H. E., Jr., and N. W. Barker. 1944. Effect of large doses of menadione bisulfite (synthetic
vitamin K) on excessive hypoprothrombinaemia induced by dicoumarol. Proc. Staff Meet. Mayo
Clin. 19:217-223.
Dam, H., and E. Sondergaard. 1953. Comparison of the effects of vitamin K~, menadione, and
Synkavit intravenously injected in vitamin K-deficient chicks. Experientia 9:26-27.
Dialameh, G. H. 1978. Stereobiochemical aspects of warfarin isomers for inhibition of enzymatic
alkylation of menaquinone-O to menaquinone-4 in chick liver. Int. J. Vitam. Nutr. Res. 48:131-135.
Dialameh, G. H., W. V. Taggart, J. T. Matschiner, and R. E. Olson. 1971. Isolation and char-
acterization of menaquinone-4 as a product of menadione metabolism in chicks and rats. Int. J.
Vitam. Nutr. Res. 41:391-400.
Dodsworth, E. 1961. Mice are spreading despite such poisons as warfarin. Munic. Eng. (London)
3746:1668.
Drummond, D. C., and E. W. Bentley. 1967. The resistance of rodents to warfarin in England and
Wales. Pp. 56-67 in EPPO Report of the International Conference on Rodents and Rodenticides,
Paris 1965. Paris: EPPO Publications.
Dubock, A. C., and D. E. Kaukeinen. 1978. Brodifacoum (Talon rodenticide), a novel concept.
Pp. 127-137 in Proc. 8th Vertebr. Pestic. Conf., Sacramento, Calif.: University of California,
Davis.
Ernster, L., M. Ljunggren, and L. Danielson. 1960. Purification and some properties of a highly
dicoumarol-sensitive liver diaphorase. Biochem. Biophys. Res. Commun. 2:88-92.
Ernster, L., C. Lind, and B. Rase. 1972. A study of DT-diaphorase activity of warfarin-resistant
rats. Eur. J. Biochem. 25:198-206.
Fasco, M. J., and L. M. Principe. 1980. Vitamin K~ hydroquinone formation catalysed by a
microsomal reductase system. Biochem. Biophys. Res. Commun. 97:1487-1492.
Fasco, M. J., and L. M. Principe. 1982. Vitamin K~ hydroquinone formation catalysed by a DT-
diaphorase. Biochem. Biophys. Res. Commun. 104:187-192.
Fasco, M. J., E. F. Hildebrandt, and J. W. Suttie. 1982. Evidence that warfarin anticoagulant action
involves two distinct reductases. J. Biol. Chem. 257:11210-11212.
Fasco, M. J., P. C. Preusch, E. F. Hildebrandt, and J. W. Suttie. 1983. Formation of hydroxy-
vitamin K by vitamin K epoxide reductase of warfarin resistant rats. J. Biol. Chem. 258:4372-
4380.
Ferguson, D. E., and C. R. gingham. 1966. Endrin resistance in the yellow bullhead, Ictaluris
natalis. Trans. Am. Fish Soc. 95:325-326.
OCR for page 97
RESISTANCE TO 4-HYDRoXYCoUMARIN ANTICOAGULANTS
97
Ferguson, D. E., D. D. Culley, W. D. Cotton, and R. P. Dodds. 1964. Resistance to chlorinated
hydrocarbon insecticides in three species of freshwater fish. BioScience 14:43-44.
Greaves, J. H. 1970. Warfarin-resistant rat. Agriculture 77:107-110.
Greaves, J. H., and P. B. Ayres. 1969. Linkages between genes for coat color and resistance to
warfarin in Rattus norvegicus. Nature (London) 224:284-285.
Greaves, J. H., and P. B. Ayres. 1973. Warfarin resistance and vitamin K requirement in the rat.
Lab. Anim. 7:141-148.
Greaves, J. H., and P. B. Ayres. 1977. Unifactorial inheritance of warfarin resistance in Rattus
norvegicus from Denmark. Genet. Res. 29:215-222.
Greaves, J. H., and P. B. Ayres. 1982. Multiple allelism at the locus controlling warfarin resistance
in the Norway rat. Genet. Res. 40:59-64.
Greaves, J. H., C. Lind, B. Rase, and K. Enander. 1973a. Warfarin resistance and DT-diaphorase
activity in the rat. F.E.B.S. Letts. 37:144.
Greaves, J. H., B. D. Rennison, and R. Redfern. 1973b. Warfarin resistance in the ship rat in
Liverpool. Int. Pest. Control. 15:17.
Greaves, J. H., B. D. Rennison, and R. Redfern. 1976. Resistance of the ship rat, Rattus rattus L.
to warfarin. J. Stored Prod. Res. 12:65-70.
Greaves, J. H., D. S. Shepherd, and J. E. Gill. 1982a. An investigation of difenacoum resistance
in Norway rat populations in Hampshire. Ann. Appl. Biol. 100:581-587.
Greaves, J. H., D. S. Shepherd, and R. Quy. 1982b. Field trials of second-generation anticoagulants
against difenacoum-resistant Norway rat populations. J. Hyg. 89:295-301.
Green, J. 1966. Antagonists of vitamin K. Vitam. Horm. 24:619-632.
Griminger, P. 1966. Biological activity of the various vitamin K forms. Vitam. Horm. 24:605-618.
Hadler, M. R. 1975. A weapon against the resistant rat. Pesticides 9:63-65.
Hadler, M. R., and R. S. Shadbolt. 1975. Novel 4-hydroxycoumarin anticoagulants active against
resistant rats. Nature (London) 253:275-277.
Hadler, M. R., R. Redfern, and F. P. Rowe. 1975. Laboratory evaluation of difenacoum as a
rodenticide. J. Hyg. 74:441-448.
Hartgrove, R. W., and R. E. Webb. 1973. The development of benzpyrene hydroxylase activity in
endrin susceptible and resistant pine mice. Pestic. Biochem. Physiol. 3:61-65.
Hermodson, M. A., J. W. Suttie, and K. P. Link. 1969. Warfarin metabolism and vitamin K
requirement in the warfarin resistant rat. Am. J. Physiol. 217:1316-1319.
Hildebrandt, E. F., and J. W. Suttie. 1982. Mechanism of coumarin action: Sensitivity of vitamin
K metabolizing enzymes of normal and warfarin-resistant rat liver. Biochemistry 21:2406-2411.
Hildebrandt, E. F., P. C. Preusch, J. L. Patterson, and J. W. Suttie. 1984. Solubilization and
characterization of vitamin K epoxide reductase from normal and warfarin-resistant rat liver
microsomes. Arch. Biochem. Biophys. 228:480-492.
Jackson, W. B., and A. D. Ashton. 1980. Present distribution of anticoagulant resistance in the
United States. Pp. 392-397 in Vitamin K Metabolism and Vitamin K-dependent Proteins, J.
Suttie, ed. Baltimore, Md.: University Park Press.
Jackson, W. B., and D. Kaukeinen. 1972. Resistance of wild Norway rats in North Carolina to
warfarin rodenticide. Science 176: 1343-1344.
Larson, A. E., P. A. Friedman, and J. W. Suttie. 1981. Vitamin K-dependent carboxylase: stoi-
chiometry of carboxylation and vitamin K 2,3-epoxide formation. J. Biol. Chem. 256:11032-
11035.
Leck, J. B., and B. K. Park. 1981. A comparative study of the effects of warfarin and brodifacoum
on the relationship between vitamin K~ metabolism and clotting factor activity in warfarin-sus-
ceptible and warfarin-resistant rats. Biochem. Pharmacol. 30:123-128.
Lehmann, J. 1943. Thrombosis: Treatment and prevention with methylenebis-(hydroxycoumarin).
Lancet 1:611-613.
Lind, C., P. Hochstein, and L. Ernster. 1982. DT-diaphorase as a quinone reductase: A cellular
OCR for page 98
98
MECHANISMS OF RESISTANCE TO PESTICIDES
control device against semiquinone and superoxide radical formation. Arch. Biochem. Biophys.
216:178-185.
Link, K. P. 1944. The anticoagulant from spoiled sweet clover hay. Harvey Lect. 34:162-216.
Lund, M. 1964. Resistance to warfarin in the common rat. Nature (London) 203:778.
Lund, M. 1981. Comparative effect of the three rodenticides warfarin, difenacoum and brodifacoum
on eight rodent species in short feeding periods. J. Hyg. 87:101-107.
Lush, I. E. 1976. A survey of the response of different strains of mice to substances metabolised
by microsomal oxidation: hexabarbitone, zoxasolamine and warfarin. Chem. Biol. Interact. 12:363-
373.
Lush, I. E., and C. J. Arnold. 1975. High coumarin 7-hydroxylase activity does not protect mice
against warfarin. Heredity 35:279-281.
MacNicoll, A. D. 1985. A comparison of warfarin-resistance and river microsomal vitamin K epoxide
reductase activity in rats. Biochim. Biophys. Acta. 840:13-20.
MacNicoll, A. D., A. K. Nadian, and M. G. Townsend. 1984. Inhibition by warfarin of liver
microsomal vitamin K-reductase in warfarin-resistant and susceptible rats. Biochem. Pharmacol.
33:1331-1336.
Martin, A. D. 1973. Vitamin K requirement and anticoagulant response in the warfarin resistant
rat. Biochem. Soc. Trans. 1:1206-1208.
Martin, A. D., L. C. Steed, R. Redfern, J. E. Gill, and L. W. Huson. 1979. Warfarin resistance
genotype determination in the Norway rat Rattus norvegicus. Lab. Anim. 13:209-214.
McKee, R. W., S. B. Binkley, D. W. MacCorquodale, S. A. Thayer, and E. A. Doisy. 1939. The
isolation of vitamin K2. J. Biol. Chem. 131:327-344.
Oliver, J. A., D. R. King, and R. J. Mead. 1979. Fluoroacetate tolerance, a genetic marker in some
Australian mammals. Aust. J. Zool. 27:363-372.
Ophof, A. J., and D. W. Langveld. 1969. Warfarin-resistance in the Netherlands. Schriften. Ver.
Wasser-, Boden-, Lufthyg. Berlin-Dahlem 32:39-47.
O'Reilly, R. A., P. M. Aggeler, M. S. Hoag, L. S. Leong, and M. Kropatkin. 1964. Hereditary
resistance to coumarin anticoagulant drugs: The first reported kindred. Clin. Res. 12:218.
Ozburn, G. W., and F. O. Morrison. 1962. Development of a DDT-tolerant strain of laboratory
mice. Nature (London) 196:1009-1010.
Pool, J. G., R. A. O'Reilly, L. J. Schneiderman, and M. Alexander. 1968. Warfarin resistance in
the rat. Am. J. Physiol. 215:627.
Preusch, P. C., and J. W. Suttie. 1984. Formation of 3-hydroxy-2-3-dihydrovitamin K~ in vivo:
Relationship to vitamin K epoxide reductase. J. Nutr. 114:902-910.
Redfern, R., and J. E. Gill. 1978. The development and use of a test to identify resistance to the
anticoagulant difenacoum in the Norway rat (Rattus norvegicus). J. Hyg. 81:427-431.
Redfern, R., and J. E. Gill. 1980. Laboratory evaluation of bromadiolone as a rodenticide for use
against warfarin-resistant and non-resistant rats and mice. J. Hyg. 84:263-268.
Redfern, R., J. E. Gill, and M. R. Hadler. 1976. Laboratory evaluation of WBA 8119 as a rodenticide
for use against warfarin-resistant and non-resistant rats and mice. J. Hyg. 77:419-426.
Ren, P., R. E. Laliberte, and R. G. Bell. 1974. Effect of warfarin, phenylindanedione and tetrach-
loropyridinol in normal and warfarin-resistant rats. Mol. Pharmacol. 10:373-380.
Ren, P., P. Y. Stark, R. L. Johnson, and R. G. Bell. 1977. Mechanism of action of anticoagulants:
Correlation between the inhibition of prothrombin synthesis and the regeneration of vitamin K~
from vitamin K~ epoxide. J. Pharmacol. Exp. Ther. 201:541-546.
Rennison, B. D., and A. C. Dubock. 1978. Field trials of WBA 8119 (PA 581, brodifacoum)
against warfarin-resistant infestations of Rattus norvegicus. J. Hyg. 80:77-82.
Richards, C. G. J. 1981. Field trials of bromadiolone against infestations of warfarin-resistant Rattus
norvegicus. J. Hyg. 86:363-367.
Roll, R. 1966. Uber die Wirkung eines Cumarinpraparates (Warfarin) auf Hausemouse (Mus musculus
L.). Z. Angewante Zool. 53:277-349.
OCR for page 99
RESISTANCE TO 4-HYDROXYCOUMARIN ANTICOAGULANTS
99
Rowe, F. P., and R. Redfern. 1965. Toxicity tests on suspected warfarin-resistant house mice (MUS
musculus L.). J. Hyg. 63:417-425.
Rowe, F. P., and R. Redfern. 1968. The effect of warfarin on plasma clotting time in wild house
mice (MUS musculus). J. Hyg. 66:159-174.
Rowe, F. P., C. J. Plant, and A. Bradfield. 1981. Trials of the anticoagulant rodenticides broma-
diolone and difenacoum against the house mouse (MUS musculus L.). J. Hyg. 87:171-177.
Sadowski, J. A., C. T. Esmon, and J. W. Suttie. 1980. Vitamin K-dependent carboxylase: Re-
quirements of the rat liver microsomal enzyme system. J. Biol. Chem. 251:2770-2776.
Saunders, G. R. 1978. Resistance to warfarin in the roof rat in Sydney, N.S.W. Search 9:39-40.
Shapiro, S. 1953. Warfarin sodium derivative (coumadin sodium): Intravenous hypoprothrombi-
naemia-inducing agent. Angiology 4:380-390.
Shearer, M. J., A. McBurney, and P. Barkhan. 1974. Studies on the absorption and metabolism of
phylloquinone (vitamin Kit) in man. Vitam. Horm. 32:513-542.
Stenflo, J., P. Fernlund, W. Egan, and P. Roepstorff. 1974. Vitamin K-dependent modifications
of glutamic acid residues in prothrombin. Proc. Natl. Acad. Sci. 71:273~2733.
Talcott, R. E., M. Rosenblum, and V. A. Levin. 1983. Possible role of DT-diaphorase in the bio-
activation of antitumour quinones. Biochem. Biophys. Res. Commun. 111:346-351.
Telle, H. J. 1967. Die Auswahl von Rodentiziden fur die Rattenvertilgungen und fur die Beibehaltung
eines rattenfreien Zustandes. Anz. Schaedlingskd. Pflanzenschutz 40:161-166.
Tishler, M., and W. L. Sampson. 1948. Isolation of vitamin K2 from cultures of a spore-forming
bacillus. Proc. Soc. Exp. Biol. Med. 68:136-137.
Townsend, M. G., E. M. Odam, and J. M. J. Page. 1975. Studies on the microsomal drug metabolism
system in warfarin-resistant and susceptible rats. Biochem. Pharmacol. 24:729-735.
Vinson, S. B., C. E. Boyd, and D. E. Ferguson. 1963. Resistance to DDT in the mosquito fish,
Gambusia a~inis. Science 139:217-218.
Wallace, M. E., and F. J. MacSwiney. 1976. A major gene controlling warfarin resistance in the
house mouse. J. Hyg. 76:173-181.
Webb, R. E., and F. Horsfall. 1967. Endrin resistance in the pine mouse. Science 156:1762.
Webb, R. E., W. C. Randolph, and F. Horsfall. 1972. Hepatic benzyprene hydroxylase activity in
endrin susceptible and resistant pine mice. Life Sci. 11:477-483.
Whitlon, D. S., J. A. Sadowski, and J. W. Suttie. 1978. Mechanism of coumarin action: Significance
of vitamin K epoxide reductase inhibition. Biochemistry 17:1371-1377.
Wood, A. W., and A. H. Conney. 1974. Genetic variation in coumarin hydroxylase activity in the
mouse (Mus musculus). Science 185:612-613.
Representative terms from entire chapter:
epoxide reductase
