Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2004-12-13
pubmed:abstractText
Juvenile three-spined stickleback (Gasterosteus aculeatus L.) is introduced as a unique model organism for both androgenic and oestrogenic endocrine action. Intersex is often used as an indicator for disruption of sexual differentiation in fish exposed to different kinds of effluents from human activities. In wild fish it has exclusively been reported in terms of feminisation due to xenoestrogens in the environment. The assumption that the intersex individuals are feminised genetic males can only be proven by genetic sex identification of the intersexual individuals. Intersex and gonadal sex reversal were induced in three-spined sticklebacks by treatment with natural and synthetic steroid hormones. Juvenile sticklebacks were exposed to three nominal concentrations of 17 beta-oestradiol (E2); i.e. 0.01, 1.0 and 10.0 microg/L; which were administered to the water either continuously from hatching to the end of the experiment (39-58 days post hatch), during the first 2 weeks after hatching only, from 14 days after hatching onwards, or during the chorionated embryo stage until hatching. Other groups were exposed to 17 alpha-ethinylestradiol (EE2) at 0.05 microg/L and 17 alpha-methyltestosterone (MT) at 1.0 microg/L (nominal concentrations). MT was applied continuously, during the first 2 weeks post hatch only, or from 14 days after hatching onwards. Gonad histology was examined and the genetic sex was identified with male sex-linked PCR markers. Treatment with oestrogens caused feminisation at the two highest E2 concentrations and with EE2. Exposure to E2 before hatching had no effect. Intersexual individuals from oestrogen treatments were genetic males. The genetic sex marker identified apparent total reversal of the gonad type of genetic males. Treatment with MT did not reveal a clear picture, since intersex was observed in both genetic females and males. MT also caused severe testis abnormalities, mainly the development of large branched cavities with unidentified origin. The process of sex differentiation is most sensitive to the influence of external steroids during the first 2 weeks after hatching. A lower incidence of intersex could also be induced in sticklebacks exposed from 14 days after hatching by E2 treatment, but not with MT. The combination of gonad histopathology with genetic sex identification in juvenile sticklebacks is suggested as a tool for detecting endocrine disruption in laboratory studies, and might become very useful in field surveys.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0166-445X
pubmed:author
pubmed:issnType
Print
pubmed:day
20
pubmed:volume
70
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
287-310
pubmed:dateRevised
2010-12-1
pubmed:meshHeading
pubmed-meshheading:15588641-Analysis of Variance, pubmed-meshheading:15588641-Animals, pubmed-meshheading:15588641-DNA Primers, pubmed-meshheading:15588641-Dose-Response Relationship, Drug, pubmed-meshheading:15588641-Environmental Monitoring, pubmed-meshheading:15588641-Female, pubmed-meshheading:15588641-Gonadal Steroid Hormones, pubmed-meshheading:15588641-Gonads, pubmed-meshheading:15588641-Hermaphroditic Organisms, pubmed-meshheading:15588641-Histological Techniques, pubmed-meshheading:15588641-Male, pubmed-meshheading:15588641-Models, Animal, pubmed-meshheading:15588641-North Sea, pubmed-meshheading:15588641-Nucleic Acid Amplification Techniques, pubmed-meshheading:15588641-Polymorphism, Restriction Fragment Length, pubmed-meshheading:15588641-Sex Determination Processes, pubmed-meshheading:15588641-Smegmamorpha, pubmed-meshheading:15588641-Sweden, pubmed-meshheading:15588641-Time Factors, pubmed-meshheading:15588641-Water Pollutants, Chemical
pubmed:year
2004
pubmed:articleTitle
The juvenile three-spined stickleback (Gasterosteus aculeatus L.) as a model organism for endocrine disruption. I. Sexual differentiation.
pubmed:affiliation
Institute of Applied Environmental Research, Stockholm University, SE-106 91 Stockholm, Sweden. edda.hahlbeck@itm.su.se
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't