Reproductive toxicity dioxins

Tietge, J.E., R.D. Johnson, K.M. Jensen, P.M. Cook, G.E. Elonen, J.D. Fernandez, G.W. Holcombe, D.B. Lothenbach, and J.W. Nichols. 1998. Reproductive toxicity and disposition of 2,3,7,8-tetrachlorodibenzo--dioxin in adult brook trout (Salvelinus fontinalis) following a dietary exposure. Environ. Toxicol. Chem. 17 2395-2407. 

Toxicology. Chlorinated dibenzo-p-dioxins (CDDs) cause chloracne, may cause hepato-toxicity, immunotoxicity, reproductive toxicity, developmental toxicity, and central nervous system toxicity, and are considered to be a human carcinogen. 

Bjerke DL, Peterson RE. 1994. Reproductive toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin in male rats different effects of in utero versus lactational exposure. Toxicol Appl Pharmacol 127 241-249. 

Peterson RE, Theobald HM, Kimmel GL. 1993. Developmental and reproductive toxicity of dioxins and related compounds Cross-species comparisons. Crit Rev Toxicol 23 283-335. 

Umbreit TH, Hesse EJ, Gallo MA. 1987. Reproductive toxicity in female mice of dioxin-contaminated soils from a 2,4,5-trichlorophenoxyacetic acid manufacturing site. Arch Environ Contain Toxicol 16 461-466. 

There is a very broad range of toxic effects of dioxins. Many of the congeners can induce toxic responses at very low dose. The most sensitive effects are immunosuppression, developmental and reproductive toxicity, as well as neurological behavioral effects. Carcinogenic effects are induced at higher exposure. TCDD was considered a complete carcinogen by the International Agency for Research on Cancer, IARC [115]. 

The extensive toxicologic data available on TCDD and other dioxin and furan isomers from animal tests for rabbit ear chloracnegenicity, teratogenicity/fetotoxicity, reproductive toxicity, mutagenicity, clastogenicity, and carcinogenicity have been compiled and reviewed in previous publications ( , 2, 4). Because of space limitations... 

Kovacic P, Pozos RS (2006) Cell signaling (mechanism and reproductive toxicity) redox chains, radicals, electrons, relays, conduit, electrochemistry and other medical implications. Birth Defects Res Part C Embryo Today Rev 78 333-344 Kraemer SA, Arthur KA, Denison MS, Smith WL, DeWitt DL (1996) Regulation of prostaglandin endoperoxide H synthase-2 expression by 2, 3, 7, 8,-tetrachlorodibenzo-p-dioxin. Arch Biochem Biophys 330 319-328... 

At other level, it has implicated chlorophyllins in conjunction with chitosan (chl-chitosan) in the reduction of the body burden of environmental dioxins, by excretion in the feces [56]. Dioxins are the most toxic artificial compounds that mainly enter in the human body through the food. They have usually long half-lives and accumulate in the adipose tissue. The adverse effects of dioxins in the human body are the following teratogenicity, reproductive toxicity, immunosuppression, hepatotoxicity. 

Based on the observations of reproductive toxicity (including endocrine disruption) in wildlife and domestic animals, as well as ongoing concerns about reproductive dysgenesis in human populations and the observed effects of industrial accidents involving MIC and dioxins, there has been increasing interest in the effects of prenatal exposures of humans to suspected endocrine disrupters and other reproductive toxicants. However, when impaired reproductive function is discovered in adults, it is difficult to comment with complete certainty on the relative contributions of prenatal versus postnatal exposures to reproductive toxicants. There is a wide array of pesticides and other organic environmental... 

Toxic equivalency factors (TEFs) are estimated relative to 2,3,7,8-TCDD, which is assigned a value of 1. They are measures of the toxicity of individual compounds relative to that of 2,3,7,8-TCDD. A variety of toxic indices, measured in vivo or in vitro, have been used to estimate TEFs, including reproductive effects (e.g., embryo toxicity in birds), immunotoxicity, and effects on organ weights. The degree of induction of P450 lAl is another measure from which estimations of TEF values have been made. The usual approach is to compare a dose-response curve for a test compound with that of the reference compound, 2,3,7,8-TCDD, and thereby establish the concentrations (or doses) that are required to elicit a standard response. The ratio of concentration of 2,3,7,8-TCDD to concentration of test chemical when both compounds produce the same degree of response is the TEF. Once determined, a TEF can be used to convert a concentration of a dioxin-like chemical found in an environmental sample to a toxic equivalent (TEQ). 

PCDDs and PCDEs, together with coplanar PCBs, can express Ah-receptor-mediated toxicity. TCDD (dioxin) is used as a reference compound in the determination of TEFs, which can be used to estimate TEQs (toxic equivalents) for residues of PHAHs found in wildlife samples. Biomarker assays for Ah-receptor-mediated toxicity have been based on the induction of P450 lAl. TEQs measured in field samples have sometimes been related to toxic effects upon individuals and associated ecological effects (e.g., reproductive success). 

Nosek, J.A., S.R. Craven, J.R. Sullivan, S.S. Hurley, and R.E. Peterson. 1992a. Toxicity and reproductive effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin in ring-necked pheasant hens. Jour. Toxicol. Environ. Health 35 187-198. 

Chlorinated organic compounds (dioxins, other halocarbons) Combustion of municipal wastes, paper processing, cleaning solvents Toxic effects including birth defects, reproductive failure, cancer, and systemic poisoning. 

Table 7 Example application of process in Box B to evaluate the risk of dioxins in Dutch sediments. No observed effect (NOEC) concentrations for chronic toxicity of dioxins in vertebrates (immune, reproductive and developmental toxicity) expressed as internal concentration (ng TEQ/g Iw). The sediment to fish bioconcentration factor is set at 4 (ng TEQ/g Organic Carbon to ng/g lipid weight in fish) based on Traas et al. (2001). Based on a species-specific biomagnification factor (BMP) from fish to animal (ng TEQ/g Iw) the internal NOEC is extrapolated to a NOEC in sediment. These data are used to construct the SSDs in Figures 5 and 6.

Leonards, P.E.G., de Vries, T.H., Minnaard, W., Stuijfzand, S., de Voogt, P., Cofino, W.P, van Straalen, N.M., van Hattum, B. (1995). Assessment of experimental data on PCB-induced reproduction inhibition in mink, based on an isomer- and congener-specific approach using 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalency. Environ Toxicol Chem 14(4) 639-652. 

Hamm JI, Chen CY, Birnbaum LS A mixture of dioxin, furans, and non-ortho PCBs based upon consensus toxic equivalency factors produces dioxin-like reproductive effects. Toxicol Sci 2003 74 182. [PMID 12730615]... 

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