Annual cycle of serum gonadal steroids and serum lipids in Capoeta capoeta umbla, Güldenstaedt, 1772 (Pisces: Cyprinidae)

Seasonal changes in serum concentrations of the testosterone in males, 17beta-estradiol in females and triglyceride and cholesterol in both sexes of Capoeta capoeta umbla were determined. Peak concentrations of testosterone (2.828 +/- 0.278 ng/mL) and 17beta-estradiol (3.182 +/- 0.116 ng/mL) occurred in May. The concentrations of testosterone and 17beta-estradiol were significantly correlated with the gonadosomatic index in both sexes. After the spawning period, steroid hormone levels significantly diminished (P < 0.05). The triglyceride concentration was highest in April (607.611 +/- 30.146 mg/dL). The serum cholesterol level showed a rising trend until April and reached peak values during this month (393.000 +/- 8.991 mg/dL). In the spawning month (May), a significant decrease was observed in triglyceride and cholesterol concentrations (P < 0.05). These results suggest that seasonal changes in both serum lipids and steroid hormones were associated with reproductive activity in C. c. umbla.