Dopamine inhibits gonadotropin secretion in the Chinese loach (Paramisgurnus dabryanus)

• DOI: 10.1007/bf01881682
• Publication Date: 2005-07-14T05:17:28Z
• Authors: Hao-Ren Lin; Chun Peng; Glen Van Der Kraak; Richard E. Peter
• Keywords: 0301 basic medicine; 03 medical and health sciences; 3. Good health

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.