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Numerous questions remain, however, making this a prime area for future study.
For example, all of the work in this area to date has focused on perinatal exposure
because of the “Fetal Basis of Adult Disease” concept. Thus, nothing is known
about the effects of EDC exposure, or hormone administration, during other life
stages such as puberty or adulthood. Impacts on the peripheral kisspeptin system
also remain unaddressed and will be a particularly critical area of future work. Two
noteworthy regions are the pancreas and the gonads because they are prime targets
for EDCs, and the physiological role of
Kiss1
and its receptor in these organs
remains to be characterized. Moreover, all of the studies to date have been per-
formed in rodents, so it has not yet been established if other species are vulnerable,
although the effects of GEN implicate sensitivity in numerous other species, includ-
ing humans. Work in sheep and other species for which there is considerable knowl-
edge about the neuroanatomical structure and function of the kisspeptin system
would be tremendously benefi cial. This is particularly critical when considering if
any of the EDC effects on the kisspeptin system observed to date are predictive of
similar effects in humans. This has become a pressing question because effects in
rodents have now been documented at EDC exposure levels considered human rel-
evant. Confi rmation of EDC effects in other species would help clarify the possibil-
ity that the human kisspeptin system may be liable to disruption and the mechanisms
by which EDCs impact human health.
In general, the possibility that EDCs can alter kisspeptin signaling pathways is
an appealing hypothesis because it would be profoundly explanatory for a suite of
adverse human health effects, both reproductive and metabolic, that currently defy
explanation. Understanding the mechanisms by which EDCs alter the ontogeny and
function of kisspeptin pathways further elucidates the consequences of endocrine
disruption, but also contributes fundamental neuroanatomical data that advances
our understanding of the evolution and sex-specifi c responsivity of this complex
system to the environment. It is a rapidly growing fi eld with far-reaching implica-
tions for toxicology, endocrinology, and evolutionary biology.
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