Steroid hormone levels and bi-directional sex change in Gobiodon histrio

✍ Scribed by F. J. Kroon; P. L. Munday; N. W. Pankhurst

• Publisher: John Wiley and Sons
• Year: 2003
• Tongue: English
• Weight: 198 KB
• Volume: 62
• Category: Article
• ISSN: 0022-1112
• DOI: 10.1046/j.1095-8649.2003.00017.x

✦ Synopsis

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.