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Steroid hormone levels and bi‐directional sex change in Gobiodon histrio
Author(s) -
Kroon F. J.,
Munday P. L.,
Pankhurst N. W.
Publication year - 2003
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 - 10.1046/j.1095-8649.2003.00017.x
Subject(s) - biology , goby , sex change , testosterone (patch) , medicine , endocrinology , sex reversal , fish <actinopterygii> , aromatase , hormone , fishery , gene , biochemistry , genetics , cancer , breast cancer
Sex change in the coral‐dwelling goby Gobiodon histrio was induced by placing two adult fish of the same sex on a coral colony. The sex change of individual fish was confirmed using histology, and whole‐body concentrations of the gonadal steroids testosterone (T), 11‐ketotestosterone (11‐KT), and 17β‐oestradiol (E 2 ) were examined. The results show that T, 11‐KT and E 2 occurred in both female and male G. histrio . E 2 concentration in females was twice that in males, while concentrations of T did not differ between the sexes. Contrary to predictions, concentrations of T and E 2 did not differ between fish that changed sex and those that did not. Most samples had 11‐KT concentrations below minimum levels of detection ( i.e. <0·15 ng ml −1 ) and were therefore not analysed statistically. The results suggest that: (i) specific activation or de‐activation of the T–E 2 (aromatase) pathway is a probable candidate for mediating serial adult sex change in G. histrio , and (ii) low levels of 11‐KT may be important in allowing serial adult sex change in G. histrio .