The endocrine system of animals is a main source of bioregulatory compounds. Hormonal actions regulate all aspects of animal life: reproduction and development, digestion, metabolism, behavioural responses etc. (Hertenstein 2006, Norris 2007). Hormones and glands of vertebrate and invertebrate endocrine system differ in structure and function, but their main regulatory role remains conserved. However, the balance among the environmental clues, hormonal signals and organisms’ responses can be easily disturbed. One of the causes of this disturbance is the presence of Endocrine Disrupting Chemicals (EDC’s) in the environment.
EDC’s are primarily man-made pollutants, structurally resembling natural hormones (Jenssen 2006) and interfering with hormonal function in a variety of ways. Some act as hormone agonists, binding to the receptors and preventing endogenous hormones from binding. An example of agonistic EDC is diethylstilbestrol (DES), a synthetic estrogen (Newbold et al 2006). Antagonistic EDC’s, which include many herbicides, act as ligands, completely or partially inhibiting receptors (Lintelmann et al 2003). The third main group is responsible for altering the hormonal pathways and reducing the number of receptors (Depledge & Billinghurst 1999).
Human activities releasing the most EDC’s into water, soil and air include metal and crude oil processing, plastic, pharmaceuticals and food manufacturing, and use of pesticides and fertilizers to increase agricultural productivity (Rhind 2009). A rapid increase in human population, expansion of human settlement and technological advances lead to a surge in environmental pollution and bioaccumulation of the pollutants in terrestrial and aquatic environments. Many EDC’s are very persistent and have a synergistic and additive mode of action (Colborn et al 1993), raising the concern about their effect on long-term ecosystem health.
The effects of EDC’s depend on the age and life stage of an animal, and may differ amongst species and individuals, depending on the degree of exposure, metabolism and other factors (Rhind 2012). Usually EDC’s do not produce obvious malformations or malfunctions (Gilbert & Epel 2009). However, they alter gene expression, particularly in early development, leading to dysfunctions of reproductive and immune system and other morphological and physiological changes (Zhou et al 2009). These changes are often manifested in adult individuals, and may be passed on to the offspring and persist for generations (Gilbert & Epel 2009). This in turn can have a profound negative effect on ecosystem health, by fuelling population declines and reduction of biodiversity (Zhou et al 2009).
The present paper reviews the evidence of endocrine disrupting chemicals’ effect on ecosystem health, with an emphasis on disruption of normal reproductive functions, including functional changes in reproductive system and alteration of reproductive behaviour. Changes in the pattern of...