Page 306 - Veterinary Toxicology, Basic and Clinical Principles, 3rd Edition

VetBooks.ir Chapter 17

Reproductive Toxicity

and Endocrine Disruption

Tim J. Evans

INTRODUCTION Unfortunately, space constraints limit the amount of
information which can be presented in this chapter, and
Reproduction is a critical biological process in all living
many of the presented topics cannot be discussed at great
systems and is required for species survival. Toxicant-
length. There are a number of recently published textbooks
induced abortions, congenital defects and infertility can
and issues of journals which cover some of these subjects
have devastating effects on livestock production. Wildlife
in greater detail and provide information which is comple-
species living in environments contaminated by industrial
mentary to what is presented in this chapter (Burrows and
and/or agricultural chemicals have experienced impaired
Tyrl, 2001; Plumlee, 2004; Naz, 2005; Golub, 2006a;
fertility and declining populations. There is growing
Hood, 2006; Jobling and Tyler, 2006; Jørgensen et al.,
concern within the scientific community and among
2006b; Mukerjee, 2006; Gupta, 2017). The reader is
government regulatory agencies about the effects of occu-
directed to these publications and other references cited in
pational and environmental exposures to reproductive tox-
this chapter in order to gain additional insight into specific
icants on human fertility.
areas of reproductive function and toxicology.
For the purposes of this chapter, the term “reproduction”
It is important that the reader understand that the areas
will be used primarily in reference to vertebrate species of
of toxicology involving reproductive toxicity and endo-
animals (especially mammals) and will be inclusive of
crine disruption, in particular, are in continual flux. New
“development,” which is sometimes treated as a separate
data and exceptions to “classical” mechanisms of action
topic in toxicology texts. This particular book chapter will
are being reported on a regular basis, and there continues
emphasize the interactions between toxicants and the male
to be ongoing debate about the various aspects of normal
and female reproductive tracts, as well as xenobiotic-
as well as xenobiotic-induced abnormal reproductive
induced effects on the growth, maturation and sexual differ-
function. Every effort has been made to accurately repre-
entiation of the embryo and fetus. Since “endocrine disrup-
sent what is currently understood about the topics of dis-
tion” is an extremely common mechanism of action for
cussion in this chapter. Controversial topics or those
xenobiotics associated with impaired reproductive function,
currently still subject to debate within the scientific com-
reproductive toxicity and endocrine disruption will be dis-
munity have been noted wherever possible.
cussed together in this chapter. Efforts will be made to clar-
ify the current terminology related to reproductive toxicity
and endocrine disruption and to introduce the reader to nor-
mal reproductive anatomy and physiology, as well as IMPORTANT DEFINITIONS
important concepts associated with embryonic and fetal AND CONCEPTS
development. Endocrine disruption in wildlife species and
Reproduction
humans and the effects of xenobiotics, including endocrine
disrupting chemicals (EDCs), on reproductive function in Reproduction in domestic, wild and laboratory vertebrates
domestic animals will be discussed along with a brief encompasses the wide range of physiological processes
description of proposed mechanisms of action and the and associated behaviors and anatomical structures
effects of some selected reproductive toxicants. involved in the production of the next generation and
Veterinary Toxicology. DOI: http://dx.doi.org/10.1016/B978-0-12-811410-0.00017-9
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