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Effects of vertebrate hormones on development and sex determination in Daphnia magna
Author(s) -
Kashian Donna R.,
Dodson Stanley I.
Publication year - 2004
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/03-372
Subject(s) - daphnia magna , biology , medicine , endocrinology , hormone , hexestrol , testosterone (patch) , diethylstilbestrol , androgen , toxicity
Daphnia (Crustacea) are extensively used as model organisms in ecotoxicology; however, little is known regarding their endocrine system. This study examines Daphnia vulnerability to vertebrate hormones. Twelve natural or synthetic vertebrate hormones were screened for activity on developmental and reproductive processes in Daphnia magna. Natural hormones tested included: β‐estradiol, gonadotropin, hydrocortisone, insulin, melatonin, progesterone, somatostatin, testosterone, and thyroxine at concentrations ranging from 1 to 100 μg/L. Synthetic hormones tested included diethylstilbestrol (estrogenic), R‐1881 (androgen), and ICI‐182,780 (antiestrogen); all hormones were screened with a 6‐d assay. Additionally, progesterone, insulin, testosterone, and thyroxine were screened for 25 d. Diethylstilbestrol decreased D. magna growth rate while thyroxine increased it. Short‐term testosterone exposure reduced D. magna fecundity; however, long‐term exposure did not, potentially indicating testosterone hydroxylation with long‐term exposure. Hormones commonly considered sex‐hormones (estrogens and androgens) in vertebrates do not appear to control sexual differentiation in D. magna; however, several vertebrate hormones do affect reproduction and development in D. magna making D. magna a potentially useful tool in monitoring for the presence of these hormones or compounds that mimic them.