The study of LHRHa2 and dopamine antagonists on gonadotropin II level in Abramis brama orientalis (Berg, 1905)

Synthetic LHRHa or its superactive analogues stimulate GTH release. It shows an overlap in the biological activity of LHRHa and GnRH in many teleost species. The aim of the present study was to investigate the effects of LHRHa2, Metoclopramide and Chlorpromazine on HPG axis and plasma levels of GHT II. Luteinizing Hormone Releasing Hormone Analogue 2 (LHRHa2) (3 mg/kg) with dopamine antagonis’s (Metoclopramide, (5 mg/kg) and Chlorpromazine (10 mg/kg)) were injected via I.M to 64 female Bream (Abramis brama orientalis) (0.71371±0.026 kg, BW) through combined and solitary teeatments: Positive Control (saline), Metoclopramide (5 mg/kg), Chlorpromazine (10 mg/kg), LHRHa2 (3mg/kg), Metoclopramide (5 mg/kg) + LHRHa2 (3 mg/kg), Chlorpromazine (10 mg/kg)+LHRHa2 (3 mg/kg), Metoclopramide (5mg/kg) + Chlorpromazine (10 mg/kg)+LHRHa2 (3 mg/kg) and Negative Control (intact). Fishes were examined through primary bleeding, injection and secondary bleeding. The time interval between two bleeding step was 5h. The GTH II measurement was conducted on the basis of RIA. Results indicate that while LHRHa2 and Metocloptamide could significantly increasethe level of GTH II (p<0.05), Chlorpromazine did not showed any significant impact on the increase of GTH II (p> 0.05). Meanwhile, compared to the complex treatments the individual treatments have had relatively significant effects (p< 0.05). All compounds showed a positive stimulation effect on the HPG axis and GTH II level in plasma.