Androgenic Modulation of Early Growth of Atlantic Cod (Gadus morhua L.) Previtellogenic Oocytes and Zona Radiata-Related Genes

• Type: Article in International Scientific Journal
• Date: 2009

Authors

kortner, tm (Author) Other; rocha, e (Author) ICBAS; arukwe, a (Author) Other

Journal

Title: Journal of Toxicology and Environmental Health - Part A

Vol. 72

Pages: 184-195

ISSN: 1528-7394

Publisher: Taylor & Francis

Indexing

ISI Web of Knowledge - 28 Citations

Scopus - 29 Citations

Scientific classification

FOS: Natural sciences > Earth and related Environmental sciences

Other information

Authenticus ID: P-003-R4D

DOI: 10.1080/15287390802539020

Abstract (EN): Available evidence suggests that androgens play critical roles in early oocyte growth and development in fish. However, the molecular mechanisms underlying this important aspect of reproductive endocrinology have not yet been established. In this study the effects of androgens (11-ketotestosterone [11-KT] and testosterone [T]) were determined on gene expression patterns and growth of cod previtellogenic oocytes, using an in vitro oocyte culture technique. Previtellogenic ovarian tissue was cultured for 5 and 10 d at different concentrations of 11-KT and T (0, 1, or 1000 M) dissolved in ethanol (0.3%). The androgen concentrations were selected as they represent physiological and supra-physiological concentrations, respectively. Quantitative polymerase chain reaction (PCR) demonstrated increased mRNA expression for five genes recently identified as androgen responsive in our subtracted cDNA library in previtellogenic cod ovary exposed in vitro to androgens. Quantitative histological analyses showed a consistent stereological validation of oocyte growth and development after exposure to androgens. In general, both 11-KT and T induced previtellogenic oocyte growth and development, and these effects were more pronounced with 11-KT exposure. Taken together, our study reveals some novel roles of androgens on the development of previtellogenic oocytes, indicating control of early follicular and oocyte growth in cod ovary. The potent effects of 11-KT on oocyte growth support our earlier hypothesis that non-aromatizable androgens play significant roles in regulating early oocyte growth with potential consequences for the fecundity process. Therefore, these novel roles of androgens as promoters of ovarian growth and development presented in this study may be useful for the aquaculture industry and for breeding of new captive and endangered species. From a toxicological point of view, the cod is a marine species and exposure to complex chemical mixtures that may exert androgenic and/or anti-androgenic effects represents an environmental issue of reasonable concern in the marine environment. Therefore, the findings in the present study represent a novel basis that can be used to determine the effects of xenoandrogens on oocyte development and fecundity in this important marine species.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12