Goldenberg N, Horowitz J F, Gorgey A, Sakharova A, Barkan A L
Department of Medicine, University of Michigan, Ann Arbor, USA.
School of Kinesiology, University of Michigan, Ann Arbor, USA.
Clin Diabetes Endocrinol. 2022 Feb 1;8(1):1. doi: 10.1186/s40842-022-00137-y.
The increase in growth hormone (GH) secretion during a prolonged fast stimulates lipolytic rate, thereby augmenting the mobilization of endogenous energy at a time when fuel availability is very low.
To identify the specific component of GH secretory pattern responsible for the stimulation of lipolytic rate during fasting in humans.
We measured lipolytic rate (using stable isotope dilution technique) after an overnight fast in 15 young, healthy, non-obese subjects (11 men and 4 women), and again on four separate occasions after a 59 h fast. These four prolonged fasting trials differed only by the contents of an infusion solution provided throughout the 59 h fasting period. Subjects were infused either with normal saline ("Control"; n = 15) or with graded doses of a GH Releasing Hormone Receptor Antagonist (GHRHa):10 μg/kg/h ("High"; n = 15), 1 μg /kg/h ("Medium"; n = 8), or 0.5 μg /kg/h ("Low"; n = 6).
As expected, the 59 h fast completely suppressed plasma insulin levels and markedly increased endogenous GH concentrations (12 h vs 59 h Fast; p = 0.0044). Administration of GHRHa induced dose-dependent reduction in GH concentrations in response to the 59 h fast (p < 0.05). We found a strong correlation between the rate of lipolysis and GH mean peak amplitude (R = 0.471; p = 0.0019), and total GH pulse area under the curve (AUC) (R = 0.49; p = 0.0015), but not the GH peak frequency (R = 0.044; p = 0.8) or interpulse GH concentrations (R = 0.25; p = 0.115).
During prolonged fasting (i.e., 2-3 days), when insulin secretion is abolished, the pulsatile component of GH secretion becomes a key metabolic regulator of the increase in lipolytic rate.
长时间禁食期间生长激素（GH）分泌增加会刺激脂肪分解速率，从而在能量供应非常低的时候增强内源性能量的动员。
确定在人类禁食期间负责刺激脂肪分解速率的GH分泌模式的特定组成部分。
我们在15名年轻、健康、非肥胖受试者（11名男性和4名女性）过夜禁食后，以及在禁食59小时后的四个不同时间点测量了脂肪分解速率（使用稳定同位素稀释技术）。这四项长时间禁食试验的不同之处仅在于整个59小时禁食期间提供的输注溶液的成分。受试者分别输注生理盐水（“对照组”；n = 15）或不同剂量的生长激素释放激素受体拮抗剂（GHRHa）：10μg/kg/h（“高剂量组”；n = 15）、1μg/kg/h（“中剂量组”；n = 8）或0.5μg/kg/h（“低剂量组”；n = 6）。
正如预期的那样，59小时禁食完全抑制了血浆胰岛素水平，并显著增加了内源性GH浓度（禁食12小时与59小时；p = 0.0044）。给予GHRHa可导致在59小时禁食期间GH浓度呈剂量依赖性降低（p < 0.05）。我们发现脂肪分解速率与GH平均峰值幅度（R = 0.471；p = 0.0019）以及曲线下总GH脉冲面积（AUC）（R = 0.49；p = 0.0015）之间存在强相关性，但与GH峰值频率（R = 0.044；p = 0.8）或脉冲间期GH浓度（R = 0.25；p = 0.115）无关。
在长时间禁食（即2 - 3天）期间，当胰岛素分泌被消除时，GH分泌的脉冲成分成为脂肪分解速率增加的关键代谢调节因子。
