Ghrelin是生长激素促泌素受体(GHS-R)的内源性配体，具有促进生长激素释放，调节食欲等广泛的生物学作用。我们在反刍动物研究已经证明外源性内皮素（ET）能够上调血浆Ghrelin 水平，但是介导该过程的内皮素受体亚型尚不清楚。本项目将用内皮素受体亚型ET-A和ET-B的高特异性阻断剂，探究介导内皮素上调羊Ghrelin分泌的内皮素受体亚型。其次，采用免疫组化技术，研究新疆细毛羊Ghrelin内分泌细胞、ET-A和ET-B受体在机体各组织的分布，并且探查在Ghrelin内分泌细胞上ET-A和ET-B受体存在的可能性，从组织学角度探明内皮素生理性上调Ghrelin分泌的可能性。最后，研究内皮素增加Ghrelin分泌的组织特异性。期望通过本项目研究为反刍动物Ghrelin调控机制提供理论依据，奠定调控动物食欲和生长实践的生理学基础。

Ghrelin is an endogenous ligand for growth hormone secretagogue receptors (GHS-R) and has a serial of biological effects, such as stimulation of growth hormone release and regulation of appetite. Our previous studies have shown exogenous endothelin (ET) can increase plasma ghrelin levels in ruminants, but the ET receptor subtypes, ET-A and ET-B, which mediated this effect are unclear. The project aims to (1) clarify the ET receptor subtype mediating ghrelin secretion using the specific antagonists for each ET receptor subtype; (2) to investigate the tissue localizations of ghrelin cells and ET-A and ET-B receptors by immunohistochemical techniques in Xinjiang fine-wool sheep; and (3) to explore whether ET-A and/or ET-B receptors are located on ghrelin cells to find the possibility of ET physiologically regulation of ghrelin secretion. We hope that the results from this project can contribute to explain the regulatory mechanism of ghrelin secretion as well as appetite and growth in ruminants.