Istituto Auxologico Italiano, IRCCS, Laboratorio Sperimentale di Ricerche Auxo-endocrinologiche, Milan and Verbania, Italy.
Horm Metab Res. 2013 Mar;45(3):239-44. doi: 10.1055/s-0032-1323767. Epub 2012 Sep 12.
It is well established that obese patients are hypo-responsive to classical GH-releasing stimuli, including aerobic exercise. Recently, we have demonstrated that whole body vibration was able to markedly stimulate GH secretion in obese patients, thus suggesting that this refractoriness is not absolute but dependent on the GH-releasing stimulus. Furthermore, we have shown the ability of a respiratory muscle endurance training (RMET) to stimulate GH and cortisol secretion in healthy subjects. The objective of this study was to evaluate the effects of RMET on GH and cortisol responses in severely obese patients. Eight severely obese patients (4 M/4 F, mean age±SEM: 22.8±1.6 years, body mass index, BMI: 39.9±1.1 kg/m2) underwent an incremental progressive RMET protocol of 11 daily sessions, obtained through the use of a specifically designed respiratory device (Spiro Tiger®). The 12th session of RMET (15 min duration: 1 min at a respiration rate of 28 acts/min, 5 min at 32 acts/min, 5 min at 34 acts/min, 4 min at 36 acts/min) was associated with blood samplings for determination of GH, cortisol, and lactate (LA) levels. An age- and sex-matched normal-weighted control group (n=7, 4 M/3 F, age: 26.1±3.1 years, BMI: 22.4±0.6 kg/m2) was also recruited. In both normal-weighted subjects and obese patients, GH secretion significantly increased after a 15-min RMET session. Although serum GH levels at 30 min were higher in normal-weighted subjects than in obese patients, there was no statistically significant difference in either GH peaks or net GH areas under the curve between the 2 groups. RMET significantly increased serum cortisol levels in normal-weighted subjects, but was associated to a progressive cortisol decline in obese patients. RMET stimulated LA production, with no significant differences in normal-weighted subjects and in obese patients. A 15-min RMET session was capable to induce a GH response in severely obese patients, which was comparable to that recorded in normal-weighted subjects. A progressive decline in serum cortisol levels occurred in obese patients after RMET, while an opposite pattern (i. e., a significant cortisol increase) was found in normal-weighted subjects. Optimization of long-term RMET protocols could represent a valid strategy to (physiologically) stimulate GH/IGF-I system in those GH hyposecretory states such as obesity.
已经证实，肥胖患者对经典的 GH 释放刺激（包括有氧运动）反应不佳。最近，我们已经证明全身振动能够显著刺激肥胖患者的 GH 分泌，这表明这种抵抗不是绝对的，而是取决于 GH 释放刺激。此外，我们已经证明呼吸肌耐力训练（RMET）能够刺激健康受试者的 GH 和皮质醇分泌。本研究的目的是评估 RMET 对严重肥胖患者 GH 和皮质醇反应的影响。
八名严重肥胖患者（4 名男性/4 名女性，平均年龄±SEM：22.8±1.6 岁，体重指数，BMI：39.9±1.1 kg/m2）接受了 11 次递增递增 RMET 方案的治疗，该方案通过使用专门设计的呼吸设备（Spiro Tiger®）获得。第 12 次 RMET （15 分钟：1 分钟以 28 次/分钟的呼吸率进行，5 分钟以 32 次/分钟进行，5 分钟以 34 次/分钟进行，4 分钟以 36 次/分钟进行）与血液采样以确定 GH、皮质醇和乳酸（LA）水平有关。还招募了一组年龄和性别匹配的正常体重对照组（n=7，4 名男性/3 名女性，年龄：26.1±3.1 岁，BMI：22.4±0.6 kg/m2）。在正常体重受试者和肥胖患者中，RMET 治疗 15 分钟后，GH 分泌明显增加。尽管正常体重受试者的血清 GH 水平在 30 分钟时高于肥胖患者，但两组之间的 GH 峰值或 GH 曲线下面积均无统计学差异。RMET 显著增加了正常体重受试者的血清皮质醇水平，但在肥胖患者中则与皮质醇水平逐渐下降相关。RMET 刺激了 LA 的产生，在正常体重受试者和肥胖患者中没有差异。15 分钟的 RMET 治疗能够诱导严重肥胖患者的 GH 反应，与正常体重受试者记录的反应相当。RMET 后肥胖患者的血清皮质醇水平下降，而正常体重受试者则出现相反的模式（即皮质醇显著增加）。优化长期 RMET 方案可能是刺激 GH/IGF-I 系统的有效策略（生理性）在那些 GH 分泌不足的状态，如肥胖。
