Department of Food Science, Aarhus University, Aarhus N, Denmark.
Section for Sport Science, Department of Public Health, Aarhus University, Aarhus C, Denmark.
J Clin Endocrinol Metab. 2022 May 17;107(6):1577-1588. doi: 10.1210/clinem/dgac112.
Little is known about changes in circulating metabolites during the menstrual cycle and how use of oral contraceptives (OCs) affects these changes.
To study fluctuations in circulating metabolite and bone marker levels during the menstrual/pill cycle in eumenorrheic women and OC users.
Plasma samples were collected from 28 eumenorrheic women and 10 OC users at 7 to 9 time points across a menstrual/pill cycle. Longitudinal and cross-sectional analyses were performed to examine the cycle- and OC-induced variations in the plasma metabolite and bone turnover marker levels.
In eumenorrheic women, plasma levels of alanine, glutamine, threonine, and tyrosine varied significantly across the menstrual cycle, and all dropped to the lowest level around day 21 of the menstrual cycle. These amino acid concentrations were negatively correlated with fluctuations in progesterone and/or estrogen levels. A between-group analysis showed that plasma levels of alanine, glutamine, glycine, proline, and tyrosine were lower in OC users than in nonusers. Concomitantly, plasma C-terminal telopeptide of type I collagen (CTX) and N-terminal propeptide of type I procollagen (PINP) levels were lower in OC users. Intriguingly, when all data were pooled, variations in CTX and PINP levels were positively correlated with fluctuations in proline and glycine concentrations (r > 0.5 or 0.3 < r < 0.5, P < 0.05).
The menstrual cycle and the use of OCs alter plasma levels of metabolites and bone turnover markers in young women. While the impact of these findings remains to be established, the lower glycine level among OC users and the accompanying lower CTX level supports that the use of OCs lowers collagen turnover in young women and may thereby have long-term implications for bone health among OC users.
关于月经周期中循环代谢物的变化以及口服避孕药（OCs）如何影响这些变化，人们知之甚少。
研究月经/服药周期中正常排卵女性和 OC 使用者循环代谢物和骨标志物水平的波动。
从 28 名正常排卵女性和 10 名 OC 使用者中采集血浆样本，在月经/服药周期的 7 到 9 个时间点采集。进行纵向和横断面分析，以研究周期和 OC 诱导的血浆代谢物和骨转换标志物水平的变化。
在正常排卵女性中，血浆中丙氨酸、谷氨酰胺、苏氨酸和酪氨酸的水平在整个月经周期中变化显著，所有这些物质的水平在月经周期的第 21 天左右降至最低。这些氨基酸浓度与孕酮和/或雌激素水平的波动呈负相关。组间分析显示，OC 使用者的血浆丙氨酸、谷氨酰胺、甘氨酸、脯氨酸和酪氨酸水平低于非使用者。同时，OC 使用者的血浆 I 型胶原 C 端肽（CTX）和 I 型前胶原 N 端肽（PINP）水平较低。有趣的是，当所有数据汇总时，CTX 和 PINP 水平的变化与脯氨酸和甘氨酸浓度的波动呈正相关（r > 0.5 或 0.3 < r < 0.5，P < 0.05）。
月经周期和 OCs 的使用改变了年轻女性的血浆代谢物和骨转换标志物水平。虽然这些发现的影响仍有待确定，但 OC 使用者中甘氨酸水平较低以及随之而来的 CTX 水平较低表明，OC 的使用降低了年轻女性的胶原蛋白周转率，可能对 OC 使用者的长期骨健康产生影响。
