Short-Term Effects of Human Kisspeptin on LH Secretion in Prussian Carp (Carassius gibelio Bloch, 1782) Females at Two Gonad Maturity Stages

Kisspeptin plays a critical role in the control of reproduction and puberty onset in vertebrates, fish including. To demonstrate the pattern of LH secretory responses [spontaneous and stimulated by GnRH analogue (Des Gly10, D-Ala6 ethylamide LHRH)] to single, intraperitoneal injection of human kisspeptin [metastin (45-54) amide], blood samples from mature Prussian carp females (at the time of gonad recrudescence and natural spawning) were collected at 5, 10, 15 and 30 minutes after injection. To test the influence of dopamine on kisspeptin action on LH release, the dopamine antagonist - pimozide - was used together with kisspeptin and GnRH analogue. At the time of gonad recrudescence kisspeptin alone had no effect on LH secretion. At the time of natural spawning the transient increase of LH levels at 10th minute post-injection was observed. Also the combination of kisspeptin and GnRHa increased LH levels in comparison to control fish at 10, 15 and 30 minutes after injections and at 10th minute kisspeptin potentiated stimulatory effects of GnRHa. No influence of kisspeptin on the spontaneous, as well as GnRHa-stimulated LH release was observed in pimozide-treated fish. Presented data suggest that the short-term response to kisspeptin is dependent on the stage of gonadal maturity