Sunday, April 12, 2009

ICCE 2009 Hong Kong

DOES TESTOSTERONE BENEFIT THE OVARIAN GROWTH IN THE EEL (ANGUILLA JAPONICA) BY ALTERING THE EXPRESSION LEVELS OF VEGF, FLK, AND EPH RECEPTOR BUT REDUCING PTEN AS WELL AS EDF-1?
Chen-Wei Chang1, Ya-Mai Chen1, Yan-Hong Lee2, and Yung-Sen Huang1*. 1Dept. Life Sci., Natl. Uni. Kaoshiung, Taiwan;2 TungKung BioTech. Res. Center., TFRI, TungKung, Taiwan. *yshuang@@XXX.XXX.tw

Previous studies showed that testosterone (T) could promote oogenesis, gonadotropins synthesis, and silvering process in the eel. In mammals, angiogenesis is important to the ovarian development, but there is no data to refer if the positive effects of T to promote oogenesis in the Japanese eel are achieved by influencing the expression levels of ovarian angiogenic-related factors. Farmed female eels were injected with catfish pituitary saline extract (CPE) or CPE supplied with T (dose=3ug T /kg BW) weekly to stimulate the ovarian development; after 9 weeks, the ovaries were sampled, RT-PCR was performed to analyze the expression levels of ovarain angiogenesis-related genes (VEGF, Flk, Angpt1, Dll4, ADAM10, Eph receptor, PTEN, EDF-1). Results indicated that GSI was significantly (p<0.05) stimulated by CPE (0.63+0.13% vs 1.50+0.31%), CPE stimulatory effect on GSI was enforced by the supplement of T (1.05+0.31% vs 2.51+0.86%, p<0.05). Expression levels of Angpt1, Dll4, and ADAM10 were not significantly (p>0.05) modified among all groups. Levels of VEGF Flk (VEGF receptor), and Eph receptor were reduced by CPE alone as compared with the Day0 control (p<0.05). Ovarian levels of VEGF and Flk (VEGF-receptor) were rescued by the supplement of T as compared those with CPE alone, since there was no difference (p>0.05) between the Day0 control and CPE+T; furthermore, the ovarian levels of Eph receptor was increased by the supplement of T as compared with CPE group or the Day0 control (p<0.01 or P<0.05, respectively). In addition, PTEN and EDF-1 (both are anti-angiogenic factors) were also significantly (p<0.01) reduced by T supplement while there was no significant (p>0.05) difference between the Day0 control and CPE alone group for these two genes. These results may highlight possible benefit roles of T on the ovarian development by altering the expression levels of VEGF-Flk as well as Eph system in the eel ovary.

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