INVESTIGADORES
RODRIGUEZ Horacio Adolfo
congresos y reuniones científicas
Título:
Ovarian Features in Xenoestrogen-determined Females of Caiman latirostris
Autor/es:
STOKER C; BELDOMENICO PM; RODRIGUEZ HA; REY F; MUÑOZ DE TORO MM; LUQUE EH
Lugar:
New Orleans, Louisiana, USA
Reunión:
Congreso; e.hormone 2004.; 2004
Institución organizadora:
Tulane/Xavier Center for Bioenvironmental Research,
Resumen:
Selection of sentinel species and biomarkers is
critical to design strategies to evaluate
environmental contamination. C. latirostris, a
species with temperature sex determination, is widely distributed in South
American aquatic ecosystems and features characteristics to be selected as
sentinel of xenoestrogens exposure. Bisphenol A (BPA), a documented
xenoestrogen, is a plasticizer used in polycarbonates and epoxy resins.
Recently, we reported sex reversal effects and/or gonadal histoarchitecture
disruption on C. latirostris exposed in ovum to 17β-estradiol (E2) or BPA. In the present study,
we assessed ovarian features in sex-reversed females of Caiman latirostris.
Eggs from 5 nests were harvested immediately after oviposition from pristine
areas and incubated at 30ºC
(female producing temperature) or 33ºC
(male producing temperature). To obtain sex reversed females, eggs incubated at
33ºC
received either E2 (1.4ppm) or BPA (140ppm). Treatments were applied topically
to the eggshell at stage 20 of embryonic development. Control eggs received
vehicle. Serial sections of paraffin-embedded gonads of 10-day and 12-month old
females were stained with a trichromic stain. In hatchling samples, ovarian
dynamics was evaluated by quantification of the different stages of oocyte growth
and maturation (oogonia, previtellogenic oocytes stages I to III). In 12
month-old caiman ovaries, polyovular follicles incidence was estimated. Ovaries
from sex-reversed female hatchlings exhibited a significant reduction in stage
III oocytes and polyovular follicles were more frequent in 12-month olds than
controls. These results demonstrate that gonadal characteristics of
xenoestrogen-determined females differ from those of temperature-determined females,
which could affect reproductive performance.