Health & Environmental Research Online (HERO)


Print Feedback Export to File
6555113 
Journal Article 
17 beta-Estradiol, but not testosterone stimulates gonadotropin II concentrations in the protandrous black porgy, Acanthopagrus schlegeli Bleeker 
Lee, YH; Du, JL; Yueh, WS; Lee, FY; Tanaka, H; Chang, CF 
1999 
Yes 
Fish Physiology and Biochemistry
ISSN: 0920-1742
EISSN: 1573-5168 
21 
4 
345-351 
English 
WOS:000085987500007 
The objective of the present study was to investigate the in vivo effects of different doses of 17 beta-estradiol (E-2) and testosterone (T) on the levels of plasma and pituitary gonadotropin II (GTH II) in 2-year-old black porgy, Acanthopagrus schlegeli, during the spawning season. Male fish were distributed among 7 groups (n = 49), control, E(2)or T (with 3 doses, 2.4 ng, 72 ng and 2.2 mu g g(-1) body weight). Fish were injected with the respective vehicle or different doses of E-2 or T on days 1 and 14. Plasma E-2 levels were significantly increased in the 72 ng E-2 group on days 8 and 14. Plasma vitellogenin levels were significantly higher in the 72 ng E-2 group on days 14 and 20, and 2.2 mu g E-2 group on days 8, 14 and 20 than those in the control group. Plasma GTH II concentrations were significantly higher in the 2.2 mu g E-2 group than in the control and other E-2 groups on days 8, 14 and 20. Pituitary GTH II contents was significantly higher in the 7.2 ng E-2 group compared to the control and other E-2 groups on day 20. Plasma GTH II concentrations were similar in the control and all the T groups on days 8, 14 and 20. None of the doses of T treatment stimulated pituitary GTH II content on day 20, although plasma vitellogenin levels were elevated. It is concluded that GTH II synthesis and secretion in black porgy is stimulated by an estrogen-specific effect. 
trout oncorhynchus-mykiss; immature rainbow-trout; pituitary-gonadal; salmo-gairdneri; sex reversal; beta-subunit; anguilla-anguilla; steroid-hormones; juvenile males; Biochemistry & Molecular Biology; Fisheries; Physiology