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Rapid bioconcentration of steroids in the plasma of three‐spined stickleback Gasterosteus aculeatus exposed to waterborne testosterone and 17β‐oestradiol
Author(s) -
Maunder R. J.,
Matthiessen P.,
Sumpter J. P.,
Pottinger T. G.
Publication year - 2007
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.2006.01303.x
Subject(s) - gasterosteus , three spined stickleback , stickleback , steroid , biology , medicine , testosterone (patch) , endocrinology , endocrine system , sex steroid , androgen , fish <actinopterygii> , steroid hormone , hormone , fishery
The relationship over time between the concentrations of two steroids, singly and in combination, in a static exposure system and in the blood of three‐spined stickleback Gasterosteus aculeatus , held within the exposure system was investigated. Groups of three‐spined stickleback were exposed (nominally) to either 1000 ng l −1 17β‐oestradiol (E2), testosterone (T) or E2 and T in combination at the same concentrations for 6 days. Both water and fish were sampled at intervals and steroid concentrations in both compartments were determined. The plasma steroid time profile revealed a rapid bioconcentration within the first 6 h of exposure. The plasma steroid levels attained at this time point (20–90 ng ml −1 ) were up to 50‐fold (E2) and 200‐fold (T) greater than the actual levels of steroid measured in the exposure water, while levels in the blood of control fish did not exceed 4 ng ml −1 . The substantial elevation of plasma steroid levels relative to the concentrations of steroid to which the fish were exposed in the ambient water gives scope for delivery of the steroids to target endocrine tissues at levels far in excess of what might be predicted on the basis of passive branchial uptake alone. These results are discussed in relation to endocrine disruption, and in particular the occurrence of effects in fish exposed to levels of endocrine active substances that are seemingly physiologically irrelevant.