Effects of Aroclor 1254 on LH and 17,20β-P secretion in female Prussian carp (Carassius gibelio Bloch) in the spawning season

Abstract

The effects of Aroclor 1254 on the secretion of luteinizing hormone (LH) and 17,20β-dihydroxy-4-pregnen-3-one (17,20β-P) in female Prussian carp (Carassius gibelio Bloch) at the time of their natural spawning were determined. Aroclor 1254 at doses of 0.01, 0.1, and 1 mg/kg body weight was dissolved in 500 ml of oil and was administered three times intraperitoneally or rectally to female Prussian carp every 24 h for three days. Blood samples were collected after 3 days of Aroclor 1254 administration to determine the LH and 17,20β-P concentrations using ELISA. At 6, 12, and 24 h after injection of gonadotropin-releasing hormone analogue (GnRH-A) blood samples were collected for stimulated LH secretion determination. Aroclor 1254 administered intraperitoneally (0.1 and 1 mg/kg)and rectally (0.01 and 1 mg/kg) significantly increased spontaneous LH secretion. In the case of GnRH-A-stimulated LH release, Aroclor 1254 (administered intraperitoneally only) at concentrations of 0.1 and 1 mg/kg significantly decreased gonadotropin release. The intraperitoneal injections of the lowest tested concentration of Aroclor 1254 also significantly decreased 17,20β-P secretion. The results show that Aroclor 1254 can affect the reproductive system of Prussian carp by changing the secretion of two very important hormones, LH and 17,20β-P, at the time of natural spawning.