Neuropeptide regulation of feeding in catfish,Ictalurus punctatus: a role for glucagon-like peptide-1 (GLP-1)?

摘要

Glucagon-like peptide 1 is a compound known to cause reduced food intake in mammals, though its action on feed intake in fish is unknown. The clear differences in the effects of GLP-l on mammalian and teleostean glucose homeostasis suggest that we cannot assume a similar action of GLP-l on feeding in mammals and fish. In this study the effects and specificity of centrally administered GLP-l on feed intake were examined. It was demonstrated that intracerebroventricular (ICY) injection of glucagon-like peptide 1 (GLP-l) in the channel catfish (Ictalurns punctatus) is a potent inhibitor of feed intake with a dose of 0.25 ng 9 -I body wt. reducing feed intake by 50%. The weak response to intraperitoneal (i.p.) and intravenous (i.v.) injection treatments with GLP-l suggests the major effects on feed intake are centrally mediated. GLP-l action on feed intake was not antagonized by ICY injection of exendin9-39. Immunoneutral- ization of GLP-l by ICY injection of antisalmon GLP-l antisera did not affect feed intake over 48 h, while ICY injection of GLP-l at a dose of 30 ng g-l body wt. reduced feed intake for over 20 h. Additionally, there is some evidence that GLP-l caused gastric evacuation. We conclude that GLP-l is a potent inhibitor of feeding in fish, but its involvement in feed intake regulation under physiological conditions remains to be clarified. Published by Elsevier Science Inc.