Feeding rainbow trout 0.3-0.4 mg dieldrinlkg/d for 9-12 weeks stimulated the biliary excretion of a subsequent dose of [¹⁴C]dieldrin by 500% and [³H]7,12- dimethylbenz[a]anthracene (DMBA) by 240%. In vitro work demonstrated that this interaction occurred without induction of the cytochrome P450 system, or other hepatocellular proteins involved in metabolism. The...
Chlordecone belongs to the class of persistent organochlorine pesticides that are remarkably resistant to environmental degradation. Even though their use was banned in the United States in 1978, these compounds can still be detected in both humans and wildlife throughout the world. Previous work has shown that the pretreatment of...
Biliary excretion of taurocholate in thermally acclimated rainbow trout was stimulated at higher environmental temperature (18 vs. 14 or 10° C)e Acute 4° C shifts in body temperature produced more pronounced changes in biliary excretion. Thermally modulated biliary excretion was negatively correlated with plasma half live of taurocholate. Absorption of...
Temperature influences the incidence of chemically induced cancer in fish,
with warmer temperatures being associated with higher cancer incidence. The
mechanisms of temperature-modulated chemical carcinogenesis in fish, however,
have not been described in detail. Therefore, one primary objective of this study
was increased understanding of how temperature-modulated genotoxicity of 7,12-...
Overtly non-toxic doses of organochlorine (OC) insecticides perturb lipid homeostasis
in mice and rats. To increase understanding of how chlordecone (CD), an OC
insecticide, modulates cholesterol (CH) homeostasis, we determined the effect of CD
pretreatment on the tissue and hepatic subcellular distribution of exogenous [¹⁴C]CH. Corn oil alone or CD...
Effects of diet on food energy utilization by grass
carp fed aquatic plants or formulated diets with varied
lipid sources and levels are presented in three
manuscripts. Significant effects of diet on food
consumption, digestion, growth and muscle fatty acid (FA)
composition of fingerling diploid grass carp fed aquatic
macrophytes...
Previous studies have shown that rainbow trout exposed to dieldrin via diet for 9 to 12 weeks increased biliary excretion of a subsequent dose of [¹⁴C]dieldrin by 500%. This was not explained by induction of the cytochrome P-450 (CYP) system involved in oxidative metabolism of these compounds. We hypothesized that...
Factors that influenced the uptake, storage, and elimination of dietary quinoline by rainbow trout (Salmo gairdneri) were studied to obtain an understanding of the mechanisms affecting the bioaccumulation of dietary contaminants in teleosts. Rainbow trout readily absorbed ¹⁴C-quinoline from pelleted food (1% ration at 138 ug quinoline/g food) and most...
Polycyclic aromatic hydrocarbons (PAHs) are significant pollutants in aquatic environments. Many are carcinogenic and lead to DNA fragmentation and adduct formation in marine and freshwater organisms. Previous research demonstrates that rainbow trout (Oncorhynchus mykiss) compensate to long-term PAH dietary exposures and reduce the DNA damage.
The aim of this study...
During the past 30 years, numerous studies have focused on the toxicities of polycyclic aromatic hydrocarbons (PAH). Laboratory and field studies have helped elucidate the detrimental effects of these chemicals on growth, reproduction and immune response. Polycyclic aromatic hydrocarbons are in the priority list of chemicals to be studied by...
Two Oregon reservoirs contaminated by different mercury
sources were compared for mercury distribution in sediment and
bioaccumulation by fish. The average mercury concentration in
the sediment of Cottage Grove reservoir (0.67 ± 0.05 μg/g dry
wt) was higher than for Dorena Reservoir (0.12 ± 0.01 μg/g dry
wt). Sediment mercury...
Liver X receptor (LXR), farnesoid X receptor (FXR) and peroxisome proliferator-activated receptor (PPAR) are adopted orphan nuclear receptors that function as lipid sensors. These receptors respond to cellular lipid levels and regulate the expression of target gene. Previously, it was demonstrated that low doses of chlordecone (CD) pretreatment disturbed exogenous...
Rats exposed to one or two doses of 60 mg mirex/kg
by gavage exhibited hypertrophied livers and various
degrees of hepatobiliary dysfunction. Although single
dosed animals demonstrated elevated whole liver bile flow
after 96 hours, the single dose was insufficient to
significantly inhibit whole liver hepatobiliary
performance as measured by...
Persistent organochlorines (OCs) bioaccumulate in aquatic biota and potentially impair reproduction via endocrine disruption. The present research evaluated estrogenic effects of the OCs, chlordecone (CD) and o,p'-DDT/DDE, and the antiestrogenicity of 3,4,5,3',4',5'-hexachlorobiphenyl (345-HCB) in juvenile rainbow trout, utilizing vitellogenesis as a biomarker. Vitellogenesis, estrogen regulated hepatic production of the yolk...
Rainbow trout were exposed to aluminum at pH 7.25 and
8.25 and four hardnesses (10, 30, 80, and 120 ppm CaCO₃)
for 96 hours in a continuous-flow system and mortality and
aluminum accumulation in the gills were determined.
Temperature, pH, and dissolved oxygen were measured
daily for each treatment. Dissolved...
The Arctic has long been considered to be a pristine environment, far
from population centers and pollution sources. The detection of synthetic
organochlorine compounds in various elements of the Arctic food web has confirmed
the global dispersion of pollutants, particularly of persistent compounds such as
organochlorines and heavy metals. Levels...
Female mink (Mustela vison) are highly sensitive to polychlorinated biphenyl (PCB)-induced reproductive impairment. The goal of this research was to develop a better understanding of the mechanism of PCB-induced effects on female mink, mink embryos, and surviving mink kits. Anestrous, juvenile female mink and pregnant, adult mink were exposed to...
The aim of this study was to assess sensitivity of early life stage zebrafish to cadmium (Cd). Embryos and larva were exposed to Cd before the formation of skeletal elements. Exposure times were selected to determine whether Cd perturbed developmental processes that lead to skeletal deformities, and to characterize the...
Whole body accumulation and tissue distribution of dieldrin
(HEOD1) in rainbow trout was studied through oral dose disposition
tests and subchronic exposures via water (0.04 and 0.08 jig dieldrin/l)
and/or diet (0.087 jig dieldrin/g fish/day). Growth and maintenance
rations of 4 and 2% body weight/day were employed. Subchronic testing
produced...
The Cottage Grove Reservoir has been impacted by a point source (Black Butte Mine), where mercury mining and processing has occurred within its watershed from the 1890's to the late 1960's. Total mercury concentrations in surface sediments transect samples, core samples, tributary samples, and representative food web species were measured...
Aquatic insects are used extensively to evaluate water quality. Despite their
widespread use as indicator organisms, relatively little is known about the
organismal characteristics that determine sensitivity differences to individual and
multiple stressors. Insects have evolved several respiratory strategies that range
from breathing atmospheric air to utilizing dissolved oxygen in...
The atmospheric transport and deposition of semi-volatile organic compounds (SOCs), including current and historic use pesticides, polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs), to mountain ecosystems may result in the exposure of tadpoles to these SOCs. This exposure has been implicated in amphibian population declines in California. Tadpoles encounter...
Protection of the quality and integrity of food supplies is of global concern. Crops can accumulate non-nutritive and sometimes toxic metals and metalloids. Accumulated metals/metalloids can come in part, from fertilizers, which may contain variable levels of non-nutritive metals or metalloids such as arsenic (As), cadmium (Cd), lead (Pb), nickel...
