Studies on steroidogenesis in zebrafish (Danio rerio)

This project was a collaboration project between the QMRI (Dr Chris Kenyon, Dr Carl Tucker, Kathryn S. Wilson) and the EBVC (Dr Sionagh Smith, and Neil McIntyre), looking into the possible use of zebrafish as a model of study of steroidogenesis. This project focused on the determination of cortisol levels in developing zebrafish, the expression of target steroidogenic enzymes (cholesterol side chain cleavage enzyme and 11-beta-hydroxylase), and the dissection of the role of 11-beta-hydroxylase using metyrapone (a competitive inhibitor of this enzyme).

My role in this project was to collaborate at the experimental design stage, interpretation of findings and histopathological interpretation of samples taken during the study. The majority of the lab work was undertaken by Kathryn S. Wilson, as part of her MSc thesis.

Zebrafish may be used as a model for the study of the synthesis of steroid hormones. In this study we analyse specific features of this animal species regarding specific steps of the synthetic pathways involved in the synthesis of steroid hormones.

Cortisol presents with a biphasic distribution, suggesting that there may be a reserve of preexisting (maternal) cortisol in the embryo, before commencement of synthesis by the embryo themselves. Broadly, this was supported by the expression profile of cholesterol side chain cleavage enzyme and 11-beta-hydroxylase.



Metyrapone driven blockage of 11-beta-hydroxylase resulted in morphological changes consistent with oedema. This may have been a result of impaired mineralocorticoid synthesis, although further studies will be required to confirm this.