Estrogen-induced ovarian development is time-limited during the temperature-dependent sex determination of the American alligator.
Gen Comp Endocrinol
; 291: 113397, 2020 05 15.
Article
en En
| MEDLINE
| ID: mdl-31991099
ABSTRACT
Many reptiles, including the American alligator, exhibit temperature-dependent sex determination (TSD), whose thermo-sensitive period for the female alligator begins at stages-15 and ends at stage-24. Estrogen signaling plays a central role in TSD, which can be overridden by an estrogen-exposure during the thermo-sensitive period. As some environmental contaminants are estrogenic, there is growing concern about their effects on the sex ratio and reproductive health of TSD-species. It is crucial to identify the timing of gonadal commitment to either ovary or testis for a better understanding of TSD and estrogen-signals. In the current study, eggs were exposed to 5 µg/g egg of 17ß-estradiol (E2) or vehicle ethanol alone at three developmental stages-22, 24, and 26 at a male-promoting temperature, which produced 81% testis in all controls. E2-exposure at stages-22 and 24 induced more ovaries than the control group, whereas the exposure at stage-26 did not induce the same outcome. These results indicated that there is a critical commitment in the testicular development between the developmental stage 24 (100% ovary in E2 Exposure) and 26 (39% ovary with E2). Based on these results, we estimated a pivotal stage as stage-25.28. Thus, a gonadal commitment to testis could be later than a known temperature-sensitive period for promoting male in TSD.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Ovario
/
Temperatura
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Procesos de Determinación del Sexo
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Caimanes y Cocodrilos
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Estrógenos
Límite:
Animals
Idioma:
En
Revista:
Gen Comp Endocrinol
Año:
2020
Tipo del documento:
Article