Effect of the organochlorine pesticide endosulfan on GnRH and gonadotrope cell populations in fish larvae.
Endocrine-disrupting chemicals can influence the hypothalamus-pituitary-gonad axis and possibly affect reproduction in vertebrates. We analyzed the effect of 30-day endosulfan (ES) exposure in sexually undifferentiated larvae of the cichlid fish Cichlasoma dimerus. The number, area, mean cytoplasmic and nuclear diameter, and mean cytoplasmic optical density of gonadotropin-releasing hormone (GnRH) I, II, and III immunoreactive (ir-) neurons and β follicle-stimulating hormone (βFSH) ir-cells were measured. Animals exposed to the highest ES concentration (0.1 μg/l) showed a decrease in GnRH I nucleus/cytoplasm area ratio upon exposure. Nuclear area and mean nuclear diameter of βFSH ir-cells was higher in ES treated fish. βFSH nucleus/cytoplasm area ratio was high in exposed animals, and animals exposed to 0.1 μg/l ES showed smaller mean cytoplasmic optical density. These findings suggest that ES affects GnRH I and βFSH protein synthesis/release. However, these responses seem to be insufficient to affect gonadal differentiation at this stage of development.
Laboratory of Animal Embryology, Department of Biodiversity and Experimental Biology, Faculty of Exact and Natural Sciences, University of Buenos Aires, Buenos Aires, C1428EHA, Argentina.
Yanina G
YG
Piazza
Matias
M
Pandolfi
Fabiana L
FL
Lo Nostro
D000818:Animals; D023681:Cichlids / Q000254:growth & development*; D004726:Endosulfan / Q000633:toxicity*; D004781:Environmental Exposure / Q000032:analysis*; D005640:Follicle Stimulating Hormone / Q000378:metabolism; D052681:Gonadotrophs / Q000166:cytology; D007987:Gonadotropin-Releasing Hormone / Q000187:drug effects*; D006066:Gonads / Q000187:drug effects; D006843:Hydrocarbons, Chlorinated / Q000633:toxicity*; D007306:Insecticides / Q000633:toxicity*; D007814:Larva / Q000187:drug effects; D009474:Neurons / Q000187:drug effects
D006843:Hydrocarbons, Chlorinated; D007306:Insecticides; D007987:Gonadotropin-Releasing Hormone; D005640:Follicle Stimulating Hormone; D004726:Endosulfan