The P450 aromatase (P450 arom) gene is asymmetrically expressed in a critical period for gonadal sexual differentiation in the chick.
Gen Comp Endocrinol
; 117(3): 325-34, 2000 Mar.
Article
en En
| MEDLINE
| ID: mdl-10764544
Steroid hormones appear to play an important role in gonadal sex differentiation of birds. Here we studied the steady-state level of the P450 arom mRNA by reverse transcriptase polymerase chain reaction (RT-PCR) in the left and the right presumptive ovary and testis of developing chicken embryos. The gonads were evaluated every hour during the undifferentiated period, at 144-156 h of incubation (h/i), and every 24 h after sexual differentiation at 168 and 192 h/i. Activity of P450 arom was determined by estrone production from [3H]androstenedione at 144-192 h/i. Moreover, morphological development of the gonad was also examined by light microscopy. Results show that onset of P450 arom mRNA and its protein activity were simultaneously detected in the left and the right ovaries at 147 h/i. Asymmetric function of P450 arom gene expression was observed at 156 h/i when morphological gonadal differentiation is first recognized. Biotransformation of [3H]androstenedione to estrone was also asymmetrically detected between the left and right gonad at 156 h/i and asymmetry was maintained throughout the analyzed stages. It is proposed that there is a gene in birds that is asymmetrically expressed in the undifferentiated stage of the female and the male gonad. In the female this gene could promote P450 arom gene expression, increasing estrogen production, which in turn could induce ovarian cortex proliferation and expression of other structural estrogen-regulated genes involved in ovarian sexual determination.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Diferenciación Sexual
/
Aromatasa
/
Expresión Génica
/
Embrión de Pollo
Límite:
Animals
Idioma:
En
Revista:
Gen Comp Endocrinol
Año:
2000
Tipo del documento:
Article
Pais de publicación:
Estados Unidos