Endocrine Disruption In Fish

There is increasing concern in the media among politicians and withinenvironmental organizations about the effects of chemicals in our environmentthat affect th... » 

There is increasing concern in the media among politicians and withinenvironmental organizations about the effects of chemicals in our environmentthat affect the endocrine systems of wildlife and humans. At its simplest theseare referred to as genderbending chemicals or environmental estrogens. Thechemicals in question pesticides PCBs plasticizers petrochemicals and avariety of industrial chemicals have been known to decrease human spermcounts cause fish to change sex and increase male genital abnormalities. Agreat deal of pressure has been placed on environmental protection agencies todevise regulatory tests for the effects of these chemicals and to requirelimitations on their manufacture and release. Fish are increasingly recognizedas an excellent model for such tests in that the aquatic environment mayprovide early warnings of the effects that these chemicals will have on humanhealth. In addition the large number of eggs which fish produce provides anexcellent model to examine the effects on female fertility. EndocrineDisruption in Fish provides a simple yet extensive background to the field offish endocrinology in order to assist those toxicologists who have a limitedbackground in either mammalian or fish endocrinology. It shows thatenvironmental estrogens do not simply affect male reproductive potential butthat they may equally well affect the female. It is possible that thesechemicals may have a complex effect on the brain hypothalamus pituitarygonad and liver of both sexes. There are many other chemicals which affect boththe gonads and other parts of the endocrine system to cause decreasedfertility abnormal sexual differentiation and behavior decreased response tostress immune deficiency or altered basal metabolism. Many thousand manmadechemicals are released into the environment but very few have been tested forendocrine disrupting activity. This book covers only the minute fraction forwhich evidence has been collected. «