Estradiol and Incubation Temperature Modulate Regulation of Steroidogenic Factor 1 in the Developing Gonad of the Red-Eared Slider Turtle1
Red-eared slider turtles are genetically bipotential for sex determination, with incubation temperature of the egg determining gonadal sex. At higher incubation temperatures, females are produced, possibly due to increased biosynthesis of estrogen. Exogenous estrogen causes the formation of ovaries,...
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Published in | Endocrinology (Philadelphia) Vol. 142; no. 4; pp. 1403 - 1411 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
Endocrine Society
01.04.2001
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Online Access | Get full text |
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Summary: | Red-eared slider turtles are genetically bipotential for sex
determination, with incubation temperature of the egg determining
gonadal sex. At higher incubation temperatures, females are produced,
possibly due to increased biosynthesis of estrogen. Exogenous estrogen
causes the formation of ovaries, and prevention of estrogen
biosynthesis results in the development of testes. In mammals,
steroidogenic factor 1 (SF-1) regulates most genes required for
estrogen biosynthesis from cholesterol. In mammals as well as red-eared
slider turtles, SF-1 is differentially expressed in males and females
during gonadogenesis. To examine a possible role for SF-1 in
temperature-dependent sex determination, we assayed its expression in
red-eared slider turtles after treatments that alter sex development
during gonadogenesis of the wild-type organism.
We examined gonadal SF-1 expression in embryos 1) incubating at three
different temperatures, 2) after treating eggs with estrogen at a
male-producing temperature, and 3) after inhibition of estrogen
biosynthesis at a female-producing temperature. Our findings suggest
that both temperature and estrogen lie upstream of SF-1 in a
sex-determining regulatory hierarchy in red-eared slider turtles and
that estrogen directly or indirectly modulates the regulation of SF-1
expression. |
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ISSN: | 0013-7227 1945-7170 |
DOI: | 10.1210/endo.142.4.8043 |