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Dopamine inhibits gonadotropin secretion in the Chinese loach (Paramisgurnus dabryanus)
H R Lin1, C Peng, G Van Der Kraak
1Department of Biology, Zhongshan University, Guangzhou, People's Republic of China.
Abstract:
The effects of dopamine on gonadotropin (GtH) secretion in sexually mature Chinese loach were investigated. Spontaneous secretion of GtH was inhibited within 1 h following an intramuscular injection of dopamine (100 μg/g body wt). Similarly, dopamine (50 and 100 μg/g body wt) caused a significant reduction in serum GtH in fish with elevated GtH levels as a result of pretreatment with gonadotropin-releasing hormone (GnRH) analogs either alone or in combination with the dopamine receptor antagonist domperidone. In summary, the present study provides direct evidence that dopamine functions as a gonadotropin-release inhibitory factor in the Chinese loach by blocking spontaneous and GnRH-stimulated GtH release.
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