Lombardi G, Corsetti R, Lanteri P, Grasso D, Vianello E, Marazzi M G, Graziani R, Colombini A, Galliera E, Corsi Romanelli M M, Banfi G
Experimental Biochemistry and Molecular Biology Laboratory, I.R.C.C.S. Istituto Ortopedico Galeazzi, Milano, Italy.
Scand J Med Sci Sports. 2014 Oct;24(5):779-87. doi: 10.1111/sms.12080. Epub 2013 May 7.
Calcium and phosphate are essential for cell functions, and their serum concentrations result from the balance between intestinal absorption, bony storage, and urinary excretion. Fibroblast growth factor 23 (FGF23), expressed by osteocytes and osteoblasts, acts in the kidney, leading to hypophosphatemia and low 1,25-dihydroxycholecalciferol synthesis, but suppresses parathyroid function. The aim of this study was to explore the effects of a high-energy demanding cycling race on this bone-kidney-parathyroid axis. We studied nine cyclists during the 2011 Giro d'Italia stage race. Pre-analytical and analytical phases followed academic and anti-doping recommendations. Serum parathyroid hormone (PTH), 25(OH)D, total calcium, inorganic phosphorus, and plasma FGF23 were measured on days -1, 12, and 22 and corrected for changes in plasma volume. Dietary calcium and phosphorus, anthropometric parameters (height, weight, and body mass index) and indexes of metabolic effort (net energy expenditure, power output) were recorded. Dietary calcium and phosphorus intakes were kept at the same levels throughout the race. Twenty-five (OH)D, PTH, and calcium concentrations remained stable. FGF23 increased 50% with a positive correlation with the indexes of metabolic effort and, consequently, phosphorous decreased, although only in the first half. The strong metabolic effort acts on the bone-kidney-parathyroid system, and the rise in FGF23 plasma concentration might be aimed at maintaining calcium and phosphorus homeostasis.
钙和磷对细胞功能至关重要，其血清浓度取决于肠道吸收、骨储存和尿排泄之间的平衡。成骨细胞和骨细胞表达的成纤维细胞生长因子23（FGF23）作用于肾脏，导致低磷血症和1,25-二羟胆钙化醇合成减少，但会抑制甲状旁腺功能。本研究的目的是探讨高能量需求的自行车比赛对该骨-肾-甲状旁腺轴的影响。我们研究了9名参加2011年环意大利自行车赛阶段赛的自行车运动员。分析前和分析阶段遵循学术和反兴奋剂建议。在第-1天、第12天和第22天测量血清甲状旁腺激素（PTH）、25（OH）D、总钙、无机磷和血浆FGF23，并对血浆量的变化进行校正。记录饮食中的钙和磷、人体测量参数（身高、体重和体重指数）以及代谢努力指标（净能量消耗、功率输出）。在整个比赛过程中，饮食中的钙和磷摄入量保持在相同水平。25（OH）D、PTH和钙浓度保持稳定。FGF23增加了50%，与代谢努力指标呈正相关，因此磷减少，尽管仅在前半程。强烈的代谢努力作用于骨-肾-甲状旁腺系统，血浆FGF23浓度的升高可能旨在维持钙和磷的稳态。
