Changes in ghrelin and ghrelin receptor expression according to feeding status.

Ghrelin, a newly identified gut hormone, has been implicated in the regulation of food intake and energy homeostasis. This study was undertaken to investigate changes in expression levels of stomach ghrelin as well as of ghrelin receptor in the hypothalamus and pituitary glands according to feeding state. Stomach ghrelin mRNA levels were increased by 48 h fasting but decreased by re-feeding. The ghrelin receptor mRNA levels of 48 h fasted rats were 8 times higher in the hypothalamus and 3 times higher in the anterior pituitary gland than levels in fed rats. In summary, not only stomach ghrelin, but also hypothalamic ghrelin receptor mRNA expression, increased during a fast. Such as enhanced ghrelin receptor expression could contribute to the amplification of ghrelin action in a negative-energy balance state.