FASTING ENHANCES GROWTH-HORMONE SECRETION AND AMPLIFIES THE COMPLEX RHYTHMS OF GROWTH-HORMONE SECRETION IN MAN
FASTING ENHANCES GROWTH-HORMONE SECRETION AND AMPLIFIES THE COMPLEX RHYTHMS OF GROWTH-HORMONE SECRETION IN MAN
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DOI：
10.1172/jci113450
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发表时间：
1988-04-01
影响因子：
15.9
通讯作者：
THORNER, MO
中科院分区：
文献类型：
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作者：
HO, KY;VELDHUIS, JD;THORNER, MO
对人体的研究表明，生长激素（GH）的间歇性释放很少见且不稳定，而且与大鼠不同的是，似乎没有明显的超日周期。然而，在非禁食受试者中的这些观察结果可能是无效的，因为混合营养素对GH释放具有不可预测的影响。此外，在进食状态下，基础GH水平经常检测不到，从而使得低幅度脉冲的识别不可靠。因此，24小时的脉冲式生长激素分泌的模式，从重复静脉采样在6个正常的成年男性受试者进行了检查，在一个控制喂养的一天，并在第一和第五天的5天的快速。GH数据进行了分析，使用两种不同的方法：一个离散的脉冲检测算法（聚类分析）和傅立叶展开时间序列，它允许固定的周期性的分泌活动被解决。5-d快速导致离散GH脉冲频率显著增加（5.8 +/- 0.7 vs. 9.9 +/- 0.7脉冲/24 h，P = 0.028），24 h综合GH浓度（2.82 +/- 0.50 vs. 8.75 +/- 0.82 μ g.min/ml; P = 0.0002）和最大脉冲幅度（5.9 +/- 1.1 vs. 12.3 +/- 1.6 ng/ml，P <0.005）。虽然多个低振幅的正弦周期性存在于控制进食日，时间序列分析显示，增强的昼夜节律和超昼夜周期的第一天和第五天的禁食。与此同时，禁食导致（第1天与第5天）生长调节素C的血清浓度（1.31 +/- 0.22 vs. 0.77 +/- 0.18 U/ml）和葡萄糖（4.9 +/- 0.2对3.2 +/- 0.2 mmol/L），游离脂肪酸（0.43 +/- 0.12对1.55 +/- 0.35 mmol/L）和乙酰乙酸（35 +/- 6对507 +/- 80 nmol/L）显著升高。我们的结论是，急性营养状况是一个重要的决定因素自发脉冲GH分泌的man. Fast-induced增强GH的释放是通过联合频率（离散脉冲）和幅度（正弦周期）调制。生长激素释放的这种改变可能在饥饿期间底物的稳态中起重要作用。
Studies in man have shown that the episodic release of growth hormone (GH) is infrequent and erratic, and unlike that in the rat does not appear to have discernible ultradian periodicities. However, these observations in nonfasted subjects may be invalid since mixed nutrients have unpredictable effects on GH release. Moreover, in the fed state basal GH levels are frequently undetectable, thus rendering the identification of low amplitude pulses unreliable. Accordingly, the 24-h pulsatile pattern of GH secretion obtained from repetitive venous sampling in six normal adult male subjects was examined during a control fed day and during the first and fifth days of a 5-d fast. The GH data were analyzed using two distinct methods: a discrete pulse detection algorithm (Cluster analysis) and Fourier expansion time-series, which allows fixed periodicities of secretory activity to be resolved. The 5-d fast resulted in a significant increase in discrete GH pulse frequency (5.8 +/- 0.7 vs. 9.9 +/- 0.7 pulses/24 h, P = 0.028), 24 h integrated GH concentration (2.82 +/- 0.50 vs. 8.75 +/- 0.82 micrograms.min/ml; P = 0.0002), and maximal pulse amplitude (5.9 +/- 1.1 vs. 12.3 +/- 1.6 ng/ml, P less than 0.005). While multiple low-amplitude sinusoidal periodicities were present on the control fed day, time-series analysis revealed enhancement of circadian and ultradian cycles on the first and fifth days of fasting. Concomitantly, fasting resulted in a decline (day 1 vs. day 5) in serum concentrations of somatomedin C (1.31 +/- 0.22 vs. 0.77 +/- 0.18 U/ml) and glucose (4.9 +/- 0.2 vs. 3.2 +/- 0.2 mmol/liter), and a marked rise in free fatty acid (0.43 +/- 0.12 vs. 1.55 +/- 0.35 mmol/liter) and acetoacetate (35 +/- 6 vs. 507 +/- 80 nmol/liter). We conclude that the acute nutritional status is an important determinant of spontaneous pulsatile GH secretion in man. Fast-induced enhancement of GH release is achieved through combined frequency (discrete pulses) and amplitude (sinusoidal periodicities) modulation. Such alterations in somatotropic hormone release may play an important role in substrate homeostasis during starvation.