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Induction of gonadal intersex in genotypic male rainbow trout ( Oncorhynchus mykiss ) embryos following immersion in estradiol‐17ß
Author(s) -
Krisfalusi Michelle,
Nagler James J.
Publication year - 2000
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/1098-2795(200008)56:4<495::aid-mrd7>3.0.co;2-e
Subject(s) - biology , rainbow trout , gonad , embryo , andrology , endocrinology , medicine , development of the gonads , estrogen , embryogenesis , period (music) , salmonidae , fish <actinopterygii> , fishery , physics , acoustics
This investigation was conducted to determine the initial period of gonadal sensitivity to estrogen in genetically male rainbow trout ( Oncorhynchus mykiss ). Fish were immersed in approximately 250 μg estradiol‐17β (E 2 )/l for two 2 hr periods during different stages of embryonic development beginning 30 days postfertilization (DPF) and continuing until 68 DPF. Histological analysis of gonad samples indicated a significant proportion of E 2 ‐treated fish had intersex gonads; these gonads were primarily comprised of testicular tissue with one or more oocytes scattered throughout. The most sensitive period for altering normal testicular development was found to occur between 44 and 51 DPF (63% intersex), while the labile period in general was determined to span 24 days (from 30 to 54 DPF). Additionally, quantitative RT‐PCR was used to measure estrogen receptor (ER) mRNA expression in whole individual untreated embryos at six weekly time points throughout the period of E 2 ‐exposure. Although the intersex condition was not observed throughout the entire E 2 ‐exposure period, ER mRNA was detected at each time point assayed. Mol. Reprod. Dev. 56:495–501, 2000. © 2000 Wiley‐Liss, Inc.