Department of Pediatrics, Aarhus University Hospital Skejby, Dk-8200 Aarhus N, Denmark.
J Clin Endocrinol Metab. 2011 Feb;96(2):468-77. doi: 10.1210/jc.2010-1995. Epub 2010 Nov 17.
Ghrelin is the endogenous agonist for the growth hormone secretagogue receptor (GHS-R). Intravenous administration of ghrelin induces insulin resistance and hyperglycemia and increases the levels of free fatty acids (FFA).
To investigate whether these effects are mediated directly by ghrelin in skeletal muscle tissue.
This study was single blinded, randomized, and placebo controlled. Eight healthy men (25.5 ± 3.1 years) received 240 min of intraarterial ghrelin infusion (4.2 ng × kg(-1) × min(-1)) into one femoral artery and intraarterial placebo infusion into the contralateral artery. Simultaneous blood samples were drawn from both femoral veins and muscle biopsies were obtained from both legs during both a basal period and during a hyperinsulinemic and euglycemic clamp period.
Ghrelin significantly elevated venous FFA levels and venous dilution of palmitate, suggestive of increased lipolysis. Glucose metabolism was unchanged, and there were no direct effects on pertinent enzymes in the insulin signaling cascade. The metabolic clearance rate of acyl ghrelin was 12.5 ± 3.3 ml × kg(-1) × min(-1). Acyl and desacyl ghrelin levels both increased.
The results of this study suggest that ghrelin may stimulate lipolysis directly in skeletal muscle.
Ghrelin 是生长激素促分泌素受体（GHS-R）的内源性激动剂。静脉内给予 Ghrelin 可诱导胰岛素抵抗和高血糖，并增加游离脂肪酸（FFA）的水平。
研究这些作用是否直接由骨骼肌组织中的 Ghrelin 介导。
本研究为单盲、随机、安慰剂对照。8 名健康男性（25.5±3.1 岁）接受 240 分钟股动脉内 Ghrelin 输注（4.2ng×kg(-1)×min(-1))，对侧股动脉给予内动脉安慰剂输注。在基础期和高胰岛素-正常血糖钳夹期同时从双侧股静脉抽取血样，并从双腿获取肌肉活检。
Ghrelin 显著升高静脉 FFA 水平和棕榈酸静脉稀释度，提示脂肪分解增加。葡萄糖代谢无变化，胰岛素信号级联中相关酶无直接作用。酰基 Ghrelin 的代谢清除率为 12.5±3.3ml×kg(-1)×min(-1)。酰基和去酰基 Ghrelin 水平均增加。
本研究结果表明，Ghrelin 可能直接刺激骨骼肌中的脂肪分解。
