Plasma steroid and corticosteroid levels in female pacu Piaractus mesopotamicus, Teleostei-Characidae.
We report the plasma levels of estradiol-17 beta (E2), testosterone (T), 17 alpha-20 beta-dihydroxy-4-pregnen-3-one (17-20P), and cortisol (F) in female pacu during the reproductive cycle (N = 44) and in females induced to ovulate with an analogue of luteinizing hormone releasing hormone (LHRHa; 10 micrograms/kg) (N = 24). The plasma hormone levels were determined by validated radioimmunoassays. Females sampled during the reproductive cycle were grouped into 4 gonadal stages: resting, early maturation, advanced maturation and regression. The calculated gonadosomatic index varied from 0.5 +/- 0.1% in resting stage to 8.1 +/- 0.6% in advanced maturation stage. The E2 and T values were highest during the early maturation stage (E2 = 2172 +/- 7.1 pg/ml; T = 412 +/- 58 pg/ml) and the F values were highest during the advanced maturation stage (132 +/- 5 ng/ml). Females induced to ovulate by LHRHa injection were sampled at 0.6, and 12 h after injection of LHRHa. Two additional groups were sampled at ovulation and 24 h after ovulation. The E2 values were highest at 6 h (2917 +/- 65 pg/ml). The T and F values were highest at ovulation (T = 3498 +/- 77 pg/ml; F = 387 +/- 16 ng/ml) and 17-20P was detected only at ovulation (2163 +/- 80 pg/ml).
Gazola
R
R
Escola de Farmácia e Odontologia de Alfenas, MG, Brasil.
Borella
M I
MI
Donaldson
E M
EM
Val-Sella
M V
MV
Sukumasavin
N
N
Fava-de-Moraes
F
F
Bernardino
G
G
D000704:Analysis of Variance; D000818:Animals; D004958:Estradiol / Q000097:blood*; D005260:Female; D005399:Fishes; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives*; D006854:Hydrocortisone / Q000097:blood*; D010062:Ovulation Induction; D011863:Radioimmunoassay; D012680:Sensitivity and Specificity; D013739:Testosterone / Q000097:blood*
D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D004958:Estradiol; D006854:Hydrocortisone