Animal studies reproductive system

Chapter 3 Health Effects Specific health effects of a given hazardous compound are reported by type of health (death, systemic, immunologic, reproductive), by route of exposure, and by length of exposure (acute, intermediate, and chronic). In addition, both human and animal studies are reported in this section. 

Data on safety have been obtained from in vitro as well as in vivo animal and human studies (see also Section 10.4). About 50 years ago, Australian farmers observed an infertility syndrome in sheep associated with the consumption of clover species (Bennets et al., 1946). The clover compounds shown to cause the infertility (genistein, daidzein, equol, biochanin A, formononetin) were members of the isoflavone family (Bradbury and White, 1951 Shutt and Braden, 1968), raising the question of whether soy might cause infertility in humans (see also Section 10.4.9). A variety of reports further supported adverse effects of isoflavones on animal reproductive systems (Santell et al., 1997 Flynn et al., 2000a,b). 

The database for HFC-134a is extensive it contains studies with both human subjects and animal models. Potentially sensitive populations, including patients with COPD and adult and pediatric asthmatic patients, were tested with direct inhalation of HFC-134a from metered-dose inhalers. The response of these groups was no different than that of healthy adults. The animal studies covered acute, subchronic, and chronic exposure durations and addressed systemic toxicity as well as neurotoxicity, reproductive and developmental effects, cardiac sensitization, genotoxicity, and carcinogenicity. The metabolism of HFC-134a is well understood, and the relationship of exposure con... 

We do not know how mirex directly affects the health of people. However, animal studies have shown that eating mirex can cause harmful effects on the stomach, intestines, liver, and kidneys. Eating mirex can also cause harmful effects on the eyes, thyroid, nervous system, and reproductive system. Since these effects occur in animals, they may also occur in people. 

Nocturnal habits and dark living environments have led to the evolution of olfaction as a major method of communication in many rodents. Although the dark and cramped habitats of many rodents complicate the study of their behavior, they can mostly be bred in large numbers under controlled conditions at modest cost and they are therefore ideal animals to use in the study of certain semiochemical phenomena. A considerable body of information on the chemical cues regulating the social and reproductive systems of these animals has thus been gathered over the last two to three decades. 

The direct effect of inhalation exposure to 1,2-dibromoethane on spermatogenesis in animals has not been studied. Nonetheless, the available data from animal studies indicate that the male reproductive system in rats is affected by exposure to 1,2-dibromoethane at high doses. In all studies discussed below, however, rats had high mortality associated with chemical toxicity and/or chemically-induced neoplasia. It is therefore difficult to attribute effects on the reproductive organs to... 

Reproductive Effects. No studies were located regarding reproductive effects in humans or animals following exposure to 3,3 -dichlorobenzidine by any route of exposme. Consequently, reproductive system disruptions are not expected in humans exposed to 3,3 -dichlorobenzidine at the levels at which it occurs at hazard waste sites. 

Studies on health effects of PAEs in humans have remained controversial due to limitations of the study design. Some findings in human populations are consistent with animal data, suggesting that PAEs and their metabolites produce toxic effects in the reproductive system. Some studies associate monoesters PAEs with semen parameters, sperm DNA damage, and hormones in human population, but none of them are statistically significant. Urinary monomethyl phthalate (MMP), monobenzyl phthalate (MBzP), mono- -butyl phthalate (MBP), MEHP, and monoethyl phthalate (MEP) were associated with poor sperm morphology and vigor, and with low sperm concentration, motility, and linearity [31-35]. However, it is not yet possible to conclude whether phthalate exposure is harmful for human reproduction. 

Studies on health effects of PAEs in humans have remained controversial due to limitations of the study designs. Some findings in human populations are consistent with animal data suggesting that PAEs and their metabolites produce toxic effects in the reproductive system. However, it is not yet possible to conclude whether phthalate exposure is harmful for human reproduction [116]. 

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