INVESTIGADORES
STOKER Cora
congresos y reuniones científicas
Título:
Ovarian Features in Xenoestrogen-determined Females of Caiman latirostris.
Autor/es:
STOKER C; BELDOMENICO P M; RODRIGUEZ H; REY F; MUÑOZ-DE-TORO M; LUQUE E H
Lugar:
New Orleans Louisiana USA
Reunión:
Congreso; e.hormone; 2004
Resumen:
Ovarian Features in Xenoestrogen-determined Females of Caiman latirostris.
Stoker C, Beldoménico PM, Rodríguez
HA, Rey F, Muñoz-de-Toro M, Luque EH
Laboratorio de Endocrinología y
Tumores Hormonodependientes, School of Biochemistry and Biological Sciences,
Universidad Nacional del Litoral.
Selection of sentinel species and
biomarkers is critical to design strategies to evaluate environmental
contamination. C. latirostris 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 ovo to 17b-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 (30°C) 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.