Abstract

threespined sticklebacks, Gasterosteus aculetaus, as well as in castrated and sham-operated nesting males. Furthermore, expression of an androgen induced kidney protein, spiggin, and 11-ketotestosterone (11KT) levels, were measured in the castrated and sham-operated males. Nesting males had significantly higher levels of both LH-β and FSH-β mRNA expression compared to post-breeding males. Furthermore, sham-operated males had significantly higher levels of LH-β mRNA and spiggin mRNA expression than the castrated fish. Expression of FSH-β, on the other hand, did not differ between castrated and sham-operatedmales. There were strong positive individual correlations between circulating levels of 11KT on the one hand and expressions of LH-β and spiggin mRNA, whereas the correlation between 11KT levels and FSH-β mRNA was weak. The negative effect of castration on β-LH mRNA indicates that gonadal hormones stimulate this expression, whereas this was not the case for β-FSH. The observed decline in β-LH expression after the end of the breeding season may be the result of cessation of the gonadal stimulation of the pituitary. On the other hand, it is not likely that this can explain the decline in FSH-β expression

Published in

Fish Physiology and Biochemistry
2001, volume: 25, number: 4, pages: 311-317
Publisher: Springer Verlag (Germany)

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