Effects of pimozide and LHRH-Aa on carp (Cyprinus carpio L.) oocyte maturation and ovulationin vivo

Effects of pimozide (Pim) and [(D-Ala⁶, Pro⁹-NEt) LHRH] (LRH-Aa) on common carp oocytes maturation and ovulationin vivo under laboratory and commercial fisheries farm conditions were investigated.Although injections of Pim and LRH-Aa at the doses of 10 mg and 50 µg/kg body weight respectively, did not increase mGtH levels (66.7–155.8 mg/ml) as much as injections of carp pituitary extract (chh) (382.1 ng/ml), induced GtH levels were high enough to induce ovulation. Changes in the ovary caused by Pim and LRH-Aa were similar to those induced by chh, and Pim injected together with LRH-Aa in a single injection gave the same results concerning ovulation induction as when they were applied separately at 6h interval.     

Dopaminergic influence on gonadotropin secretion in white sturgeon (Acipenser transmontanus)

The effects of dopamine on the secretion of two sturgeon gonadotropins (stGTH I and stGTH II) in sexually mature male white sturgeon (Acipenser transmontanus) were evaluated. In Experiment I, sturgeon were given intraperitoneal injections of physiological saline (PS), dopamine (100 mg kg⁻¹), the gonadotropin releasing hormone analog D-Ala⁶-des-Gly¹⁰-GnRH ethylamide (GnRHA) (10 μg/kg⁻¹), and a combination of GnRHa and dopamine. Fish receiving only GnRHa had significantly higher (p < 0.05) concentrations of plasma stGTH I and stGTH II compared to fish receiving PS, dopamine, or a combination of GnRHa and dopamine. Two hours following its administration, dopamine was effective in decreasing plasma concentrations of both stGTHs that were previously elevated by GnRHa. Dopamine or PS administered by themselves did not alter plasma concentrations of either stGTH. In Experiment II, sturgeon injected intraperitoneally with a combination of GnRHa and pimozide had significantly higher (p < 0.05) concentrations of plasma stGTH I and stGTH II compared to males receiving GnRHa or pimozide alone. While this effect of GnRHAa + pimozide was observed in the spring, no such potentiation was seen in these fish during the summer (Experiment III). These results represent the first evidence of dopaminergic inhibition of GnRH-induced pituitary gonadotropin secretion in Chondrostean fish.     

多巴胺拮抗物 pimozide(PIM)或排除剂 reserpine(RES)和促黄体素释放激素类似物(LHRH-A)诱导养殖鱼类促性腺激素分泌和排卵的研究

由多巴胺拮抗物PIM或排除剂RES组成的高效新型鱼类催产合剂能有效的诱导主要的淡水养殖鱼类促性腺激素分泌和产卵，其中青鱼催产率为80％，鲢鱼为84％，鳙鱼和草鱼为88％，长春鳊为94％，鲮鱼为96％。试验表明这种催产剂的主要优点是：催产效果高而稳定，可以完全取代鱼脑垂体；对当年第二次成熟和产卵的亲鱼同样有效；有利于保护亲鱼；节省劳力和成本。