High temperature inhibits cyp19a1a expression and estradiol synthesis in pejerrey (Odontesthes bonariensis) ovaries in vitro

MIRANDA LA; ELISIO M; STRUSSMANN CA

Buenos Aires

Simposio; 7th International Symposium On Fish Endocrinology; 2012

7th International Symposium On Fish Endocrinology

High water temperature impairs fish reproduction inhibiting gonad steroidogenesis and gametogenesis. In pejerrey, it has been demonstrated that water temperatures above 23° C affect all levels of reproductive axis blocking its spawning. Because it remains unclear if high temperature directly affects fish ovary functions independently of pituitary control, in vitro pejerrey ovary assays were done. Fragments of approximately 200 mg of vitelogenic ovaries were incubated with 10 UI of HCG at 20 °C or at 27° C. After 3, 6, 9 and 12 hs, culture media were removed for testosterone (T) and estradiol (E2) analysis, and ovary fragments were taken to measure the expression levels of FSH-R and cyp19a1a. The results showed that E2 levels and cyp19a1a expression significantly decreased since 3 hs of culture at 27 °C compared with 20 °C, meanwhile T levels and FSH-R expression remained without changes. These findings demonstrated that ovary functions are directly disrupted by high temperature independent of the brain-pituitary axis, being the inhibition of aromatase expression and consequently E2 synthesis a primary effect provoking female reproductive impairment.