Details

Autor(en) / Beteiligte

• Lee, Yan-Horn
• Du, Jin-Lien
• Yen, Fan-Pin
• Lee, Cheng-Yen
• Dufour, Sylvie
• Huang, Jing-Duan
• Sun, Lian-Tien
• Chang, Ching-Fong

Titel

Regulation of plasma gonadotropin II secretion by sex steroids, aromatase inhibitors, and antiestrogens in the protandrous black porgy, Acanthopagrus schlegeli Bleeker

Ist Teil von

• Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology, 2001-06, Vol.129 (2-3), p.399-406

Ort / Verlag

England: Elsevier Inc

Erscheinungsjahr

2001

Quelle

MEDLINE

Beschreibungen/Notizen

• Plasma gonadotropin II (GTH II) concentrations were significantly higher (approx. 15–20-fold) in estradiol-17β (E2) treated (1.0 μg or 2.5 μg g−1 body weight) female black porgy from days 4 to 12 compared with the control. E2 (1 μg g−1 wt.) had a stronger stimulation on plasma GTH II in early recrudescent phase (low GSI) males (11-fold) than in high GSI and late spermiating males (2.6-fold, P<0.05). No effect of androgens (testosterone, T; 5α-dihydrotestosterone, DHT) on plasma GTH II levels was observed either sex. The levels of plasma GTH II were stimulated in 1,4,6-androstatriene-3,17-dione (ATD, 1 μg g−1, 2 μg g−1 body wt.) and fadrozole-treated (1 μg g−1, 3 μg g−1 body wt.) groups compared to control. Tamoxifen (1 μg g−1, 3 μg g−1 body wt.) but not enclomiphene could stimulate high GTH II levels in plasma. In another experiment of ATD in combination with T, T treatment further attenuated the ATD stimulation of plasma GTH II levels. We concluded that GTH II secretion is positively regulated by an estrogen-specific effect in female and male black porgy. Gonadal stage had significant effects on the responsiveness of GTH II to E2 stimulation in males. A negative aromatase-dependent feedback control of plasma GTH II levels was also suggested in the protandrous black porgy, Acanthopagrus schlegeli.