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المؤلفون: Crain Da, Spiteri Id, Louis J. Guillette
المصدر: Toxicology and Industrial Health. 15:181-186
مصطلحات موضوعية: 0301 basic medicine, Organochlorine contaminants, medicine.medical_specialty, 030102 biochemistry & molecular biology, Health, Toxicology and Mutagenesis, Public Health, Environmental and Occupational Health, Zoology, 010501 environmental sciences, Biology, Toxicology, In ovo, 01 natural sciences, 03 medical and health sciences, chemistry.chemical_compound, Endocrinology, chemistry, Internal medicine, medicine, Atrazine, Reproductive system, 0105 earth and related environmental sciences
الوصف: Wild alligators exposed to persistent organochlorine contaminants, municipal waste compounds, and contemporary-use herbicides exhibit reproductive alterations that are thought to be caused by endocrine disruption. This study tests the hypothesis that these alterations, at least in part, result from exposure of alligator embryos to contemporary-use herbicides. Alligator eggs were collected early in development, exposed to estradiol-17β, atrazine, or 2,4-D (at dosages of 0.14, 1.4, and 14 ppm, plus a dosage of 0.014 ppm for estradiol-17β only) before the period of gonadal differentiation, and incubated at a temperature that would produce either 100% males or 100% females. Analysis of histology was performed on the gonads and reproductive tracts of hatchlings. In females, epithelial cell height of the Müllerian duct and medullary regression of the ovary were assessed, whereas in males, sex-cord diameter was measured. Eggs incubated at the female-determining temperature produced all female hatchlings, whereas the estradiol-17β treatments caused the production of females at the male-determining temperature. Neither atrazine nor 2,4-D had this effect. Both Müllerian duct epithelial cell height and medullary regression were increased in estradiol-treated animals, but no differences were noted between herbicide-treated alligators and controls. A previous study found that male alligators exposed to 14 ppm atrazine had elevated gonadal aromatase activity, but there was no difference in sex-cord diameter in this or any other treatment group. Additionally, we observed that hepatic aromatase activity was not altered by in ovo exposure to any of the treatments. These results indicate that these herbicides alone are not responsible for the gonadal abnormalities previously reported for juvenile alligators from Lake Apopka and emphasize the importance of anlyzing both the function ( i.e., steroidogenic enzyme activity) and the structure ( i.e., histological analysis) of the reproductive system. Structural assessment alone may be insufficient for detecting subtle endocrine alterations.
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المؤلفون: Elizabeth A. Guillette, Louis J. Guillette
المصدر: Toxicology and Industrial Health. 12:537-550
مصطلحات موضوعية: Male, medicine.medical_specialty, Health, Toxicology and Mutagenesis, Reproductive tract, Wildlife, Environmental pollution, Biology, Toxicology, 03 medical and health sciences, Human health, 0302 clinical medicine, Environmental health, medicine, Animals, Humans, 030212 general & internal medicine, Gonadal Steroid Hormones, Health consequences, Mechanism (biology), Reproduction, Public health, Public Health, Environmental and Occupational Health, Abnormalities, Drug-Induced, Environmental Exposure, 030210 environmental & occupational health, Environmental Pollutants, Female, Public Health
الوصف: At the onset of the industrial age, environmental contaminants began to pose a major threat to the health of wildlife. That threat appears to continue today. In the last three decades, the focus of our concern on the health consequences of environmental pollution has been on lethal, carcinogenic, and/or extreme teratogenic manifestations. Evidence from a number of sources suggests that another mechanism, endocrine-disruption, also must be examined. There is excellent laboratory and field evidence that man-made chemicals (xenochemicals) released into the environment act as hormones or antihormones. They act as endocrine-disrupting contaminants (EDCs). The release of EDCs occurred in the past and continues today.The development of the reproductive system is vulnerable to perturbation by EDCs. Wildlife studies demonstrate that both sexes are affected and experience modifications of gonadal and reproductive tract development or functioning and abnormal synthesis or metabolism of hormones. A number of abnormalities seen in the reproductive system of various wildlife species correlate with similar abnormalities described as rising in human populations. We suggest that wildlife are excellent sentinels of ecosystem health. Data from these wildlife studies present models and methodologies for examining human health.
URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::f8ea7006e6bdec466c9c197f0c02a10e
https://doi.org/10.1177/074823379601200325
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