| Research Abstract |
Leptin plays an important role in regulation of food intake and metabolism in rats and mice. However, central administration of leptin did not alter food intake of chicks. Feeding behavior was stimulated by low levels of norepinephrine and decreased by further production of norepinephrine in chicks. Central GLP-1 suppressed food intake and induced sleeping behavior. Sleeping behavior was also induced by central morphine and consequently food intake was suppressed. Relationships between GLP-1 and morphine in the brain were studied, but no interaction was detected. GLP-1 inhibited water intake as well as food intake. It was suggested that N-terminal histidine had a key role for the action of GLP-1. Central gastrin as a brain-gut peptide inhibited both food intake and food passage from the crop. CCK, having a similar amino acid sequence for gastrin, suppressed food intake and the effect was stronger in a large size molecule than in a small one. Central histamine, a-MSH and bombesin strongly inhibited food intake. In mammalian species, orexin, MCH, galanin and motilin have been recognized as an orexigenic factors. However, these peptides did not enhance food intake of chicks. Peripheral administration of erythromycin, having an action like motilin, did not show any effects for feeding. Orexigenic actions of both NPY and norepinephrine were depressed by the inhibition of nitric oxide synthesis in the brain. Release of arginine vasotocin inhibited by opioid peptide. Synthesis and release of arginine vasotocin was simultaneously decreased under a hypertonic condition.
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