The relationships between gonad development and sex steroid levels at different ages in Acipenser schrenckii.

Summary The histological developments of the gonad and the associated sex steroid levels were determined in the breeding stocks of Acipenser schrenckii (age classes 1 to 5) maintained under natural temperature regimes (December 4°C; August 26°C). Early sex differentiation was observed in 1-year-old fish, while testosterone (T) and 17β-estradiol (E2) levels ranged from T 1.1 to 3.4 nmol l−1 (average 1.8 nmol l−1), and E2 varied from 24 to 85 pmol l−1 (av. 50.3 pmol l−1). Gonadal status of 2-year-old males was in stage II while ovaries were at stage I, exhibiting T levels from 1.2 to 4.4 nmol l−1 (av. 2.2 nmol l−1), and E2 concentrations from 10 to 97 pmol l−1 (av. 38.9 pmol l−1). At the age of 3 years, the testes in males were at developmental stage III while the ovaries remained in stage I, with T levels ranging from 1.3 to 21.7 nmol l−1 (av. 9.6 nmol l−1), and E2 concentrations ranging from 17 to 108 pmol l−1 (av. 44.8 pmol l−1). At the age of 4 years, testes in males were at developmental stage III while ovaries in females had reached stage II, with T concentrations ranging from 7.3 to 52.6 nmol l−1 (av. 26.3 nmol l−1), and E2 levels between 13 and 86 pmol l−1 (average 55.3 pmmol l−1). In 5-year-old fish, the testes reached maturity stage while the ovaries were mostly in stage III, with T values from 5.7 to 44.2 nmol l−1 (av. 13.9 nmol l−1), and E2 concentrations from 21 to 453 pmol l−1 (av. 137.7 pmol l−1). Data demonstrated large differences in sex steroid levels among immature Amur sturgeon, and testicular maturation occurred earlier than ovarian maturation.

[1]  L. Bayunova,et al.  Serum sex steroids and their specific cytosol binding in the pituitary and gonads of Russian sturgeon (Acipenser gueldenstaetdii Brandt) during final maturation. , 2006 .

[2]  E. Couto,et al.  Sex steroids and oocyte maturation in the sterlet (Acipenser ruthenus L.) , 2006 .

[3]  L. Bayunova,et al.  Sex steroids and cortisol levels in the blood of stellate sturgeon (Acipenser stellatus Pallas) during final maturation induced by LH‐RH‐analogue , 2006 .

[4]  G. Moberg,et al.  In vitro steroidogenesis by testicular fragments and ovarian follicles in a hybrid sturgeon, Bester , 1999, Fish Physiology and Biochemistry.

[5]  P. Williot,et al.  Plasma sex steroids and vitellogenin levels in stellate sturgeon (Acipenser stellatus Pallas) during spawning migration in the Danube River , 2002 .

[6]  D. Kime,et al.  Sex steroid profiles in female and male stellate sturgeon (Acipenser stellatus Pallas) during final maturation induced by hormonal treatment , 2002 .

[7]  K. Yamauchi,et al.  Effects of estradiol‐17β and 17α‐methyltestosterone on gonadal sex differentiation in the F2 hybrid sturgeon, the bester , 2002 .

[8]  K. Yamauchi,et al.  Histological observations of gonadal sex differentiation in the F2 hybrid sturgeon, the bester , 2001 .

[9]  S. Su.  Embryonic and larval development of Amur sturgeon Acipenser schrenckii , 2000 .

[10]  I. Barannikova.  Sex steroids in the serum of Caspian sturgeons and their specific cytosol binding in brain and gonads during the migratory cycle , 1999 .

[11]  K. Yamauchi,et al.  Ovarian development and serum sex steroid and vitellogenin profiles in the female cultured sturgeon hybrid, the bester , 1996 .

[12]  Z. Yaron.  Endocrine control of gametogenesis and spawning induction in the carp , 1995 .

[13]  R. Wright,et al.  A radioimmunoassay for 17α20β-dihydroxy-4-pregnen-3-one: Its use in measuring changes in serum levels at ovulation in Atlantic salmon (Salmo salar), coho salmon (Oncorhynchus kisutch), and rainbow trout (Salmo gairdneri) , 1982 .

[14]  R. Wright,et al.  A radioimmunoassay for 11-oxotestosterone: Its application in the measurement of levels in blood sebum of rainbow trout (S. Gairdneri). , 1977, Steroids.