Effect of 17beta-estradiol, o,p'-DDT, octylphenol and p,p'-DDE on gonadal development and liver and kidney pathology in juvenile male summer flounder (Paralichthys dentatus).

The intent of this study was to compare histopathologically the effect of 17beta-estradiol (E(2)), o,p'-DDT, octylphenol and p,p'-DDE on gonadal development and liver and kidney condition in sexually immature (juvenile) summer flounder (Paralichthys dentatus). The dorsal sinus of 2-year-old juvenile male summer flounder was injected with the appropriate amount of chemical incorporated in coconut oil. A second identical injection was administered 2 weeks later. Fish were sampled at 4, 6 and 8 weeks after the initial injection and observed histopathologically. In control fish, spermatogenesis was predominantly in mid to late maturation. In fish treated with 1.0 and 10.0 mg/kg E(2) spermatogenesis regressed to primary spermatogonia or an immature functional state. Testicular atrophy and spermatogonial proliferation was also observed. An eosin-positive, hyaline material was found in the gonad, liver and kidney. This eosinophilic material also stained positive with Periodic Acid Schiff (PAS) stain. Treatment of 30 or 60 mg/kg o,p'-DDT elicited altered gonadal development similar to that observed with E(2) treated fish. Octylphenol treatment of 100 mg/kg resulted in reduced testicular size, ducts full of sperm, numerous spermatogonia and PAS positive material in the testis with no developing sperm cysts. No effect on liver or gonad tissues was observed with p,p'-DDE at the concentrations tested. All chemicals tested, with exception of p,p'-DDE, altered gonadal development, whereas only E(2) caused histopathological changes in the liver and kidney. Estrogenic activity induced the liver to produce a vitellogenin (VtG)-like substance and inhibited testicular maturation. As a result, both the lack of target cells for VtG and a continuous supply of VtG from the liver allowed the hyaline material to accumulate in the liver, testis and kidney causing histopathological changes.

Effects of estrogenic (o,p'-DDT; octylphenol) and anti-androgenic (p,p'-DDE) chemicals on indicators of endocrine status in juvenile male summer flounder (Paralichthys dentatus).

Laboratory experiments were conducted with male summer flounder to assess the value of selected measures of endocrine status in fish as indicators of exposure to endocrine-disrupting contaminants. Effects of 1,1,1-trichloro-2-(p-chlorophenyl)-2-(o-chlorophenyl) ethane (o,p'-DDT), octylphenol and 1,1-dichloro-2,2-bis (p-chlorophenyl) ethylene (p,p'-DDE) on hepatosomatic and gonadosomatic indices, plasma steroid hormone levels, vitellogenin production, and gonadal development were evaluated in laboratory-raised, juvenile male summer flounder. Flounder were injected twice with test chemical in a coconut oil carrier. Each chemical was tested at three different concentrations. Estrogenic (o,p'-DDT; octylphenol) and anti-androgenic (p,p'-DDE) chemicals were evaluated alone and in combination (octylphenol plus o,p'-DDT or p,p'-DDE). Additionally, some fish were treated with the natural ligand for the estrogen receptor, 17beta-estradiol. Blood and tissues from different fish in each treatment were sampled 4, 6 and 8 weeks after the first injection. Fish exposed to a combination of o,p'-DDT plus octylphenol were also sampled after 15 weeks. In all cases, responses of fish exposed to a test chemical were compared to control fish sampled at the same time. The following significant differences, relative to controls, were observed in at least one sampling time or at least one concentration of chemical. 17beta-Estradiol-treated flounder exhibited decreased gonadosomatic index (GSI), altered hepatosomatic index (HSI), elevated plasma estradiol, reduced plasma testosterone, and high levels of plasma vitellogenin. Fish treated with o,p'-DDT showed lower GSI, no change in HSI or plasma estradiol, depression of plasma testosterone, and induction of vitellogenesis. Octylphenol treatment resulted in lower GSI, no change in HSI, initially increased plasma estradiol and decreased testosterone, and no vitellogenin production. p,p'-DDE treatment did not significantly alter any indicator relative to controls. In experiments using combinations of chemicals, flounder receiving o,p'-DDT plus octylphenol had lower GSI after 8 weeks and elevated plasma estradiol after 15 weeks exposure. Fish treated with p,p'-DDE plus octylphenol for 8 weeks exhibited a significantly lower GSI. Overall, lower GSI and plasma testosterone levels, relative to controls, were consistent indicators of exposure to estrogenic chemicals in juvenile male flounder. No indicators were found that would identify exposure to the mammalian anti-androgen p,p'-DDE.

Vitellogenin-induced pathology in male summer flounder (Paralichthys dentatus).

Male summer flounder (Paralichthys dentatus) were given two injections (initially and 2 weeks later) of 17beta-estradiol (E2) totaling 0.2 (2 x 0.1), 2.0 (2 x 1.0) or 20.0 (2 x 10.0) mg E2/kg body weight. Blood and tissue samples were collected 4, 6 and 8 weeks after the initial injection in the (2 x 0.1) mg/kg treatment, 4, 6, 8, and 15 weeks after the first injection in the (2 x 1.0) mg/kg treatment and at 4 weeks only in the (2 x 10.0) mg/kg treatment. Five of the 12 fish injected twice with 10.0 mg/kg were moribund before the first sampling period. Circulating levels of vitellogenin (VTG) in the blood of all E2-injected fish from all treatments were comparable with those concentrations found in the blood of wild male carp (Cyprinus carpio) and walleye (Stezostedion vitreum) previously collected near a sewage treatment plant (0.1-10.0 mg VTG/ml plasma). Excessive hyalin material accumulated in the livers, kidneys and testes of the treated fish. A portion of that material was identified as VTG by immunohistochemistry. The accumulation of VTG, and possibly other estrogen-inducible proteins, resulted in hepatocyte hypertrophy, disruption of spermatogenesis, and obstruction or rupture of renal glomeruli.

Contaminant levels in harbor seals from the northeastern United States.

The concentrations of polychlorinated biphenyls (PCBs), organochlorine pesticides, polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzofurans (PCDF), polychlorinated dibenzo-p-dioxins (PCDD), and mercury (Hg) were determined in blubber and liver tissues of harbor seals (Phoca vitulina) collected along the northeast coast of the U.S. Average PCB concentrations in seal blubber (sum of congeners) were 12.0 micrograms/g (wet weight) with a range of 7.30 to 24.3 micrograms/g in 1980 and 6.66 micrograms/g (wet weight) with a range of 2.61 to 11.3 micrograms/g in 1990-1992. Comparisons between blubber data from this study and previous work indicated that the concentration of PCBs along the northeast coast of the U.S. may have decreased over the past twenty years. The average p,p'-DDE concentrations in seal blubber were 10.9 micrograms/g (wet weight) in 1980 with a range of 6.95 to 21.9 micrograms/g and 4.12 micrograms/g (wet weight) with a range of 1.83 to 7.84 micrograms/g in 1990-1992. Only trace amounts of PCDFs and PCDDs were found in a few blubber samples; levels in most tissues were below detection (3-5 pg/g) (wet weight). Trace amounts (< 30 ng/g) of phenanthracene, anthracene, and alkylated MW-178 compounds were found in some seal samples; all other PAH compounds were below the detection level (5-15 ng/g). Toxic equivalents (TEQ) of selected coplanar and mono-ortho PCB congeners and relative toxic equivalents (RTE) (pg total TEQ/microgram total PCB) were calculated, using recently proposed dioxin toxic equivalent factors (Ahlborg et al. 1994). The TEQs ranged from 41 to 315, and the RTEs ranged from 2.25 to 16.3.(ABSTRACT TRUNCATED AT 250 WORDS)

Organochlorine, organobromine, metal, and selenium residues in bottlenose dolphins (Tursiops truncatus) collected during an unusual mortality event in the Gulf of Mexico, 1990.

Polychlorinated biphenyls (PCBs), cis-chlordane, oxychlordane, heptachlor epoxide, mirex, hexachlorobenzene (HCB), lindane, octachlorostyrene (OCS), p,p'-DDE,p,p'-DDT, dieldrin, triphenylphosphate (TPP), polybrominated biphenyls (PBBs), and polybrominated diphenyl ethers (PB-DPEs) were measured in the blubber, and five metals (mercury, lead, cadmium, chromium, and manganese) and selenium were measured in the liver of bottlenose dolphins (Tursiops truncatus) obtained from the Gulf of Mexico during an unusual mortality event in 1990. The collection of animals included fetuses, sucklings (< 1 year old), immature dolphins (2-5 years old), and adults of both sexes. PCBs, p,p'-DDE, HCB, and PBDPEs were detected in the blubber of each animal. Mean concentrations of organic contaminants were generally highest in adult males. p,p'-DDE was the single component analyte measured at the highest concentration. Immature females had greater concentrations of most chlorinated organics than adult females. Mercury and cadmium concentrations in liver increased with increasing age-class. The correlation between mercury and selenium in all animals was r = 0.96, with a mole ratio of 0.90. Concentrations of lead, manganese, cadmium, and chromium did not follow any particular age-class trend.

Histopathologic lesions in sea otters exposed to crude oil.

Following the Exxon Valdez oil spill in Prince William Sound, Alaska, sea otters (Enhydra lutris) that appeared to be contaminated with oil, that were in danger of becoming contaminated, or that were behaving abnormally were captured and taken to rehabilitation centers. Exposure to oil was assessed by visual examination when otters arrived at the centers. Degree of oil exposure was graded according to the following criteria: oil covering greater than 60% of the body--heavily contaminated; oil covering 30-60% of the body--moderately contaminated; oil covering less than 30% of the body or light sheen on fur--lightly contaminated. If there was no oil visible, otters were considered uncontaminated. Tissues from 51 oil-contaminated sea otters (14 males, 37 females) and from six uncontaminated sea otters (three males, three females) that died in rehabilitation centers were examined histologically. Among oil-contaminated sea otters, 19/46 had interstitial pulmonary emphysema, 13/40 had gastric erosion and hemorrhage, 11/47 had centrilobular hepatic necrosis, 14/47 had periportal to diffuse hepatic lipidosis, and 10/42 had renal tubular lipidosis. Of the uncontaminated sea otters, 1/6 had gastric erosion and hemorrhage and 1/6 had diffuse hepatic lipidosis. Histologic examinations were performed on tissues from five sea otters (three males, two females) found dead with external oil present 15 to 16 days after the spill. Periportal hepatic lipidosis and renal tubular lipidosis were found in 3/5, and interstitial pulmonary emphysema was found in 1/5. Tissues from six apparently normal sea otters (four males, two females) collected from an area not affected by an oil spill were examined histologically, and none of these lesions were found. We conclude that interstitial pulmonary emphysema, centrilobular hepatic necrosis, and hepatic and renal lipidosis of sea otters were associated with exposure to crude oil. Gastric erosion and hemorrhage may have been associated with stress of captivity and/or oil exposure.

Differential susceptibility of immature rat testes to doxorubicin at critical stages of maturation. Biochemical and functional assessment.

The toxic effects of doxorubicin on the reproductive system of the male rat were studied at different susceptible stages of postnatal development. A multidisciplinary approach including the assessment of histopathological, functional and biochemical parameters was chosen. Groups of male rats were treated once with the compound (3 mg/kg) on postnatal day 6, 16, 24 or 45. Both the onset of reproductive capacity and fertility were determined by serially mating ten animals per group for 12 weeks beginning at the age of 45 days. Reproductive organ weights, sperm counts and epididymal androgen binding protein (ABP) were measured at intermediate (80-day-old rats) or terminal sacrifice (129-day-old rats). Age dependent differential doxorubicin toxicity was evident. Treatment of 6-day-old animals with doxorubicin severely impaired development of reproductive functions. Treatment of 16-day-old animals reduced fertility throughout the mating study, as well as body and reproductive organ weights and sperm counts. Initial toxicity was observed in the group treated at 24 days of age; particularly, low reproductive organ weights and low sperm counts were found. These findings proved reversible towards the end of the study. Neither biochemical nor functional impairment of the reproductive system could be observed in the group treated at 45 days of age.

Testicular toxicity of antineoplastic drugs during postnatal development of the rat.

A multidisciplinary approach was chosen to assess effects of anticancer drugs on the postnatally developing reproductive system. Male rats were treated once with doxorubicin (3 mg/kg bw i. p.) on either postnatal day 6, 16, 24, or 45. Mating studies, sperm counts, estimation of androgen binding protein and assessment of pathological parameters were performed at the time of onset of reproductive capacity of the controls and for 12 weeks thereafter. Male reproductive toxicity of doxorubicin was clearly dependent on the age at the time of treatment, being greatest for 6 day old animals and absent for 45 day old animals.