Age-related changes in ghrelin function, ghrelin concentration and ghrelin related molecules expression in the growing chickens.

Ghrelin感染了鸡的胃肠道。Ghrelin引起的腺胃收缩和生长激素促分泌素受体(GHS-R1a)mRNA的表达随年龄增加而减少。腺胃和血浆中的Ghrelin浓度在孵化后升高，在30日龄时达到平台期。Ghrelin和Ghrelin-O-乙酰转移酶(山羊)mRNAs的表达也有随年龄增长而降低的趋势。Ghrelin基因的表达与血浆Ghrelin无相关性。Ghrelin浓度与GHS-R1a和山羊mRNAs表达之间的反向关系表明Ghrelin诱导的Ghrelin受体和合成酶下调。Ghrelin、山羊和GHS-R1a mRNAs在脑内的表达模式随生长阶段的变化具有明显的区域依赖性。本研究结果表明，生长激素释放蛋白系统在生长鸡的脑和胃肠道中的生理作用发生了变化。

Ghrelin contracted a chicken gastrointestinal tract. The ghrelin-induced contraction and expression of growth hormone secretagogue receptor (GHS-R1a) mRNA in the proventriculus decreased depending on age. Ghrelin concentrations in the proventriculus and plasma increased after hatching and reached plateau at 30 days. Expression of ghrelin and ghrelin-O-acetyltransferase (GOAT) mRNAs also tended to decrease depending on age. Expression of ghrelin mRNA did not show any correlation with plasma ghrelin. Inverse relationships between ghrelin concentration and GHS-R1a and GOAT mRNAs expression are indicative for a ghrelin-induced downregulation of the ghrelin receptor and synthetic enzyme. The expression pattern of ghrelin, GOAT and GHS-R1a mRNAs in the brain distinctly change in region-dependent manner on growing stage. The present results indicated that physiological role of ghrelin system changes in the brain and gastrointestinal tract of growing chickens.