To develop laboratory cultures for suitable aquatic invertebrates and establish their base line
endocrinology for use in risk assessment of AACs and further EDCs.
The current knowledge about endocrine regulation of development and reproduction in aquatic invertebrates
is extremely limited and progress on understanding endocrine disruption in invertebrates has been hampered by
the lack of detailed insights in their endocrinology. It has been shown that androgens do not only occur in the
three different invertebrate groups under investigation (rodents, echinoderms, crustaceans, molluscs) but also
that they play a functional role at least in molluscs and echinoderms (comp. report of the
EDIETA workshop).
The weakest evidence was found in crustaceans, where a number of different humoral signalling systems have
been described, like ecdysteroids, neuropeptides, methyl farnesoate, the so-called "androgenic hormone" and
vertebrate-type sex steroids (17β-estradiol, testosterone, progesterone). Although an external administration of
testosterone has been shown to stimulate the conversion of ovaries into testes in female crabs, to induce a
hypertrophy and hyperplasia of the androgenic gland, the functional role of androgens has been questioned
in this group. The strongest evidence for a physiological use of vertebrate-type steroids within the invertebrates
is coming from molluscs and echinoderms. Both use additionally neuropeptides which might act as releasing
hormones comparably to the situation in vertebrates. Studies by the University of Frankfurt, the Technical
University of Denmark and the University of Milano have established that some EDCs that interact with
hormone receptors in vertebrates cause reproductive effects in all three invertebrate groups. These chemicals
include mainly xeno-estrogens like bisphenol A, octylphenol, nonylphenol, but also synthetic and natural
estrogens. Therefore, it is likely that these invertebrates are also sensitive to AACs.
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