Toshinai K, Mondal M S, Nakazato M, Date Y, Murakami N, Kojima M, Kangawa K, Matsukura S
Third Department of Internal Medicine, Miyazaki Medical College, Miyazaki, 889-1692, Japan.
Biochem Biophys Res Commun. 2001 Mar;281(5):1220-5. doi: 10.1006/bbrc.2001.4518.
Ghrelin is a novel gut-brain peptide that binds to the growth hormone secretagogue receptor (GHS-R), thereby functioning in the regulation of growth hormone (GH) release and food intake. Ghrelin-producing cells are most abundant in the oxyntic glands of the stomach. The regulatory mechanism that governs the biosynthesis and secretion of ghrelin has not been clarified. We report that ghrelin mRNA expression in the gastric fundus was increased, but that ghrelin peptide content decreased after a 48-h fast. Both values returned to control levels after refeeding. The ghrelin plasma concentration in the gastric vein and systemic venous blood increased after 24- and 48-h fasts. Furthermore, des-octanoylated ghrelin and n-octanoylated ghrelin were found in rat stomach, with the ratio of des-octanoylated ghrelin to n-octanoylated ghrelin markedly increased after fasting. The ghrelin mRNA level in the stomach also increased after administration of insulin and leptin. Conversely, db/db mice, which are deficient in the leptin receptor, had lower ghrelin mRNA levels than control mice. These findings suggest that this novel gastrointestinal hormone plays a role in the regulation of energy balance.
胃饥饿素是一种新型的肠脑肽，它与生长激素促分泌素受体（GHS-R）结合，从而在调节生长激素（GH）释放和食物摄入中发挥作用。产生胃饥饿素的细胞在胃的泌酸腺中最为丰富。胃饥饿素生物合成和分泌的调控机制尚未阐明。我们报告称，禁食48小时后，胃底中胃饥饿素mRNA表达增加，但胃饥饿素肽含量下降。重新进食后，这两个值均恢复到对照水平。禁食24小时和48小时后，胃静脉和体静脉血中的胃饥饿素血浆浓度升高。此外，在大鼠胃中发现了去辛酰化胃饥饿素和正辛酰化胃饥饿素，禁食后去辛酰化胃饥饿素与正辛酰化胃饥饿素的比例显著增加。给予胰岛素和瘦素后，胃中胃饥饿素mRNA水平也升高。相反，缺乏瘦素受体的db/db小鼠的胃饥饿素mRNA水平低于对照小鼠。这些发现表明，这种新型胃肠激素在能量平衡调节中发挥作用。
