Ovarian Features in Xenoestrogen-determined Females of Caiman latirostris

STOKER C, BELDOMÉNICO PM, RODRÍGUEZ HA, REY F, MUÑOZ-DE-TORO M, LUQUE EH

New Orleans, Louisiana, U.S.A

Congreso; e.hormone 2004; 2004

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 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 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.