Fish Physiology and Biochemistry

, Volume 43, Issue 6, pp 1517–1529 | Cite as

Androgen-induced pseudo-hermaphroditic phenotypes in female Brevimyrus niger Günther 1866 (Teleostei, Mormyridae)

  • Sonja K. Stell
  • Peter Moller


This paper explores the plasticity of sexually dimorphic characters in subadult female Brevimyrus niger, an African weakly electric mormyrid species. Thirty-five fish were exposed in a staggered fashion (five fish a week) to aromatizable 17α-methyltestosterone over a period of 7 weeks; 18 fish served as untreated controls. 17α-MT induced precocious vitellogenesis that mirrored the natural maturational process during seasonal ovarian recrudescence. At the same time, 17α-MT exposure resulted in complete masculinization of the females’ anal fin support structure normally observed during rainy season in adult males. We discuss possible hormonal mechanisms acting along the brain-pituitary-gonad axis that would explain the occurrence of precocious vitellogenesis and the male-typical transformation of the female’s anal fin ray bases. Our findings are relevant to commercial aquaculture as the use of 17α-MT in fish hatcheries can pose serious environmental issues.


Mormyridae Brevimyrus niger 17α-Methyltestosterone Developmental plasticity Pseudo-hermaphroditism 



This study was supported by PSC-CUNY grant (#623140031) and CUNY Hunter College Equipment grant to PM, as well as a grant from the National Center for Research Resources (RR03037-NCRR–NIH). The content of this article is solely the responsibility of the authors and does not necessarily represent the official views of NCRR or NIH. We like to acknowledge the use of the radiographic facility in the Department of Ichthyology at the American Museum of Natural History, and wish to thank staff in the department, Dr. B. Brown, R. Arindell, and D. Rodriguez for their assistance. Dr. C.B. Braun and two anonymous reviewers provided invaluable comments for improvement of this paper.

Compliance with ethical standards

All procedures were approved by the Hunter College Animal Care and Use Committee (Protocol No. PM/SH/AV/7/00).


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© Springer Science+Business Media Dordrecht 2017

Authors and Affiliations

  1. 1.Department of PsychologyHunter CollegeNew YorkUSA

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