Endocrine disruption in aquatic vertebrates.
Environmental compounds can interfere with endocrine systems of wildlife and humans. The main sink of such substances, called endocrine disrupters (ED), are surface waters. Thus, aquatic vertebrates, such as fish and amphibians, are most endangered. ED can adversely affect reproductive biology and the thyroid system. ED act by (anti)estrogenic and (anti)androgenic modes of action, resulting in abnormal sexual differentiation and impaired reproduction. These effects are mainly driven by direct interferences of ED with sex steroid receptors rather than indirectly by impacting synthesis and bioavailability of sex steroids, which in turn might affect the hypothalamic-pituitary-gonadal axis. Recent findings reveal that, in addition to the human-produced waste of ED, natural sources, such as parasites and decomposition of leaves, also might act as ED, markedly affecting sexual differentiation and reproduction in fish and amphibians. Although the thyroid system has essential functions in both fish and amphibians, amphibian metamorphosis has been introduced as the most sensitive model to detect thyroidal ED; no suitable fish model exists. Whereas ED may act primarily on only one specific endocrine target, all endocrine systems will eventually be deregulated as they are intimately connected to each other. The recent ecotoxicological issue of pharmaceutically active compounds (PhACs) present in the aquatic environment indicates a high potential for further endocrine modes of action on aquatic vertebrates by ED derived from PhACs, such as glucocorticoids, progestins, and beta-agonists.
Kloas
Werner
W
Department of Endocrinology, Institute of Biology, Humboldt University, Berlin, Germany. werner.kloas@igb-berlin.de
Urbatzka
Ralph
R
Opitz
Robert
R
Würtz
Sven
S
Behrends
Thomas
T
Hermelink
Björn
B
Hofmann
Frauke
F
Jagnytsch
Oana
O
Kroupova
Hana
H
Lorenz
Claudia
C
Neumann
Nadja
N
Pietsch
Constanze
C
Trubiroha
Achim
A
Van Ballegooy
Christoph
C
Wiedemann
Caterina
C
Lutz
Ilka
I
D000818:Animals; D052244:Endocrine Disruptors / Q000378:metabolism*; D006801:Humans; D008386:Marine Biology; D004364:Pharmaceutical Preparations; D012098:Reproduction; D013961:Thyroid Gland / Q000378:metabolism; D014714:Vertebrates / Q000378:metabolism*
D052244:Endocrine Disruptors; D004364:Pharmaceutical Preparations