Nicoll Justin X, Fry Andrew C, Mosier Eric M
California State University, Northridge, Department of Kinesiology, Northridge, CA, USA.
University of Kansas, Department of Health, Sport, and Exercise Sciences, Lawrence, KS, USA.
Steroids. 2021 Aug;172:108859. doi: 10.1016/j.steroids.2021.108859. Epub 2021 May 8.
Consumption of caffeine or caffeine containing pre-workout supplements (SUPP) augments steroid hormone responses to resistance exercise (RE). However, the activation of glucocorticoid (GR) and androgen receptors (AR) following RE SUPP has not been investigated. The purpose of this study was to determine the influence of a pre-workout supplement on AR and GR phosphorylation following RE.
In a randomized, counter-balanced, double-blind, placebo-controlled, within-subject crossover study, ten resistance-trained males ((X¯±SD, age = 22 ± 2.4 yrs, hgt = 175 ± 7 cm, body mass = 84.1 ± 11.8 kg) performed four sets of 8 repetitions of barbell back squats at 75% of their 1-repetition maximum (1-RM) with two minutes of rest between sets and a fifth set of barbell back squats at 60% of 1-RM until concentric failure. A SUPP or flavor and color matched placebo (PL) was consumed 60-minutes prior to RE. Vastus lateralis muscle biopsies were obtained prior to supplementation at rest (BL), and ten minutes post-exercise (POST). Biopsies were analyzed for phosphorylated GR (ser134, ser211, and ser226) and phosphorylated AR (ser81, ser213, ser515, ser650) via western blotting.
pGRser134 decreased, and pGRser226 increased following RE (p < 0.05) with no difference between conditions (p > 0.05). pGRser211 was unchanged after RE (p > 0.05). pARser515 increased, and total AR expression decreased after RE (p < 0.05) in SUPP only. Testosterone and cortisol were not different between SUPP and PL at POST (p > 0.05).
RE influences AR and GR phosphorylation, and SUPP minimally influences this response in the early recovery period.
摄入咖啡因或含咖啡因的运动前补充剂（SUPP）可增强类固醇激素对阻力运动（RE）的反应。然而，运动前补充剂后糖皮质激素（GR）和雄激素受体（AR）的激活情况尚未得到研究。本研究的目的是确定运动前补充剂对阻力运动后AR和GR磷酸化的影响。
在一项随机、平衡、双盲、安慰剂对照、受试者内交叉研究中，10名经过阻力训练的男性（（X¯±SD，年龄 = 22 ± 2.4岁，身高 = 175 ± 7厘米，体重 = 84.1 ± 11.8千克）以其1次重复最大值（1-RM）的75%进行四组每组8次的杠铃后深蹲，组间休息两分钟，然后以1-RM的60%进行第五组杠铃后深蹲直至向心收缩力竭。在阻力运动前60分钟摄入SUPP或口味和颜色匹配的安慰剂（PL）。在休息时补充前（BL）以及运动后10分钟（POST）获取股外侧肌活检样本。通过蛋白质印迹法分析活检样本中磷酸化的GR（丝氨酸134、丝氨酸211和丝氨酸226）和磷酸化的AR（丝氨酸81、丝氨酸213、丝氨酸515、丝氨酸650）。
阻力运动后pGRser134降低，pGRser226升高（p < 0.05），各条件之间无差异（p > 0.05）。阻力运动后pGRser211无变化（p > 0.05）。仅在补充剂组中，阻力运动后pARser515升高，总AR表达降低（p < 0.05）。运动后SUPP组和PL组的睾酮和皮质醇无差异（p > 0.05）。
阻力运动影响AR和GR磷酸化，运动前补充剂在早期恢复阶段对这种反应的影响最小。
