Publication Abstract

Further refinement of the non-invasive procedure for measuring steroid production in the male three-spined stickleback, Gasterosteus aculeatus.

Further refinement of the non-invasive procedure for measuring steroid production in the male stickleback, Gasterosteus aculeatus L.

M. Sebire*, I. Katsiadaki*, A.P. Scott*

Measurement of steroids in water has already been shown to be an effective way of studying the reproductive endocrinology of the male stickleback, Gasterosteus aculeatus L. without having to sacrifice the fish. In the present paper, we have repeated our previous observation on the existence of a compound (other than 11-ketotestosterone; 11-KT) in water that cross-reacts in the 11-KT radioimmunoassay. However, the amounts of this compound are not sufficient to warrant a separation step prior to carrying out an assay. We have also confirmed the lack of association between androstenedione levels in water and those in plasma. We have for the first time shown that: the amounts of testosterone released into the water are positively correlated to the amounts in plasma; the sampling procedure (placing the fish for 30 min in 50 ml water) has no effect on the rate of release of cortisol but causes a rapid drop in the rate of release of 11-KT (which means that the fish cannot be sampled twice in short succession); physical interaction between two nesting males (which is accompanied by aggression) significantly increases the rate of release of 11-KT, T and Ad (but not of cortisol; the rate of release of 11-KT is at its maximum between 2 and 5 h after exposure.

Reference

M. Sebire*, I. Katsiadaki*, A.P. Scott* (2009) Further refinement of the non-invasive procedure for measuring steroid production in the male stickleback, Gasterosteus aculeatus L. Journal of Fish Biology 75:2082-2094

M. Sebire*, I. Katsiadaki*, A.P. Scott*

Journal of Fish Biology 75; 2082-2094