Gulick C N, Peddie M C, Jowett T, Hackney A C, Rehrer N J
School of Physical Education, Sport & Exercise Sciences, University of Otago, PO Box 56, Dunedin 9054, New Zealand.
Department of Human Nutrition, University of Otago, PO Box 56, Dunedin 9054, New Zealand.
Int J Sci Res Methodol. 2020 Sep;16(3):61-77. Epub 2020 Sep 30.
Insulin-like growth factor 1 (IGF-1) is a dichotomous hormone. While beneficial for growth/repair, and regulating muscle hypertrophy, high concentrations of IGF-1 are associated with increased risk of cancer and mortality. Factors thought to mediate IGF-1 include dietary protein and exercise. The purpose of this study was to analyze acute effects of dietary protein and/or exercise on plasma free IGF-1 and the time-course thereof to inform individuals who may benefit from increased IGF-1 (muscle growth/repair) or reduced IGF-1 (risk/diagnosis of cancer). Twenty-four participants (11 females, 24.9±4.6y) completed the three-way crossover study consisting of: (1)a high protein (42g) meal; (2)exercise (20min with four 30sec sprints); and (3)exercise followed by a high protein meal. Blood samples were collected fasted at rest, immediately after rest (or 5min after exercise), and at regular intervals throughout a 5h recovery. An additional fasted venipuncture was performed the morning following each condition (24h after baseline). Free IGF-1 was higher at immediately after exercise in the exercise condition (p=0.04). In the protein condition the 24h IGF-1 was 17.5% higher (p=0.02) than baseline. IGF-1 did not change over time in response to exercise with protein. The data gleaned from this study can enhance the knowledge of the time-course effects from protein and/or exercise on IGF-1. This study can provide a foundation for future research to investigate optimal timing and dosage to enhance muscle protein synthesis for athletes, as well as investigate whether consistent high protein meals may chronically elevate IGF-1 and increase the risk of deleterious health outcomes.
胰岛素样生长因子1（IGF-1）是一种具有双重作用的激素。虽然它对生长/修复有益，并能调节肌肉肥大，但高浓度的IGF-1与癌症风险和死亡率增加有关。据认为，介导IGF-1作用的因素包括膳食蛋白质和运动。本研究的目的是分析膳食蛋白质和/或运动对血浆游离IGF-1的急性影响及其时间进程，以便为可能从IGF-1增加（肌肉生长/修复）或IGF-1降低（癌症风险/诊断）中获益的个体提供信息。24名参与者（11名女性，年龄24.9±4.6岁）完成了这项三因素交叉研究，该研究包括：（1）一顿高蛋白（42克）餐；（2）运动（20分钟，包含四次30秒冲刺）；（3）运动后进食高蛋白餐。在静息空腹状态下、静息后立即（或运动后5分钟）以及在5小时恢复过程中的定期时间点采集血样。在每种情况后的早晨（基线后24小时）进行额外的空腹静脉穿刺。在运动情况下，运动后立即的游离IGF-1水平较高（p=0.04）。在蛋白质摄入情况下，24小时时的IGF-1比基线水平高17.5%（p=0.02）。在蛋白质与运动同时进行的情况下，IGF-1水平未随时间变化。从这项研究中收集的数据可以增进对蛋白质和/或运动对IGF-1时间进程影响的了解。这项研究可以为未来的研究提供基础，以调查最佳时间和剂量，从而增强运动员的肌肉蛋白质合成，同时还可以研究持续的高蛋白餐是否会长期升高IGF-1并增加有害健康后果的风险。
