Lariviere F, Moussalli R, Garrel D R
Department of Medicine, University of Montreal Medical School, Quebec, Canada.
Am J Physiol. 1994 Sep;267(3 Pt 1):E422-8. doi: 10.1152/ajpendo.1994.267.3.E422.
Possible changes in protein metabolism during the menstrual cycle were examined in eight healthy women who received an intravenous infusion of L-[1-13C]leucine on time during the follicular phase of the menstrual cycle and one time during the luteal phase. Enrichment of plasma [13C]ketoisocaproate and expired 13CO2 were measured to determine leucine flux and oxidation. Continuous respiratory gas exchange measurements were made for the determination of CO2 production, O2 uptake, and energy expenditure. The day of the tests, plasma thyroid hormone concentrations were measured as well as plasma and urinary cortisol. Leucine flux was higher during the luteal than during the follicular phase (2.25 +/- 0.39 vs 2.01 +/- 0.42 mumol.kg-1.min-1; P < 0.01), and leucine oxidation was also increased during the luteal phase [0.52 +/- 0.14 vs. 0.44 +/- 0.05 mumol.kg-1.min-1 (P < 0.05) for luteal and follicular phases, respectively]. Resting energy expenditure was increased during the luteal phase compared with the follicular phase (218 +/- 22 and 199 +/- 12 kJ/h, respectively). Plasma free triiodothyronine (T3) and the ratio triiodothyronine/reverse triiodothyronine (T3/rT3) were both significantly higher during the luteal phase [7.7 +/- 0.6 vs. 7.1 +/- 0.8 and 4.65 +/- 0.80 vs. 3.93 +/- 0.70 for T3 and T3/rT3, respectively (P < 0.05 for both comparisons)]. This study shows small changes in protein metabolism during the menstrual cycle in women, with an increase in oxidative leucine metabolism during the luteal phase. The concomitant increase observed in circulating free T3 raises the possibility that fluctuations in protein metabolism and thyroid hormones throughout the menstrual cycle are causally related.
在月经周期的卵泡期和黄体期，对8名健康女性进行了L-[1-¹³C]亮氨酸静脉输注，以此研究月经周期中蛋白质代谢可能发生的变化。通过测量血浆[¹³C]酮异己酸的富集量和呼出的¹³CO₂来确定亮氨酸通量和氧化情况。连续进行呼吸气体交换测量以测定二氧化碳产生量、氧气摄取量和能量消耗。在测试当天，还测量了血浆甲状腺激素浓度以及血浆和尿液中的皮质醇。黄体期的亮氨酸通量高于卵泡期（分别为2.25±0.39与2.01±0.42μmol·kg⁻¹·min⁻¹；P<0.01），黄体期的亮氨酸氧化也增加了[黄体期和卵泡期分别为0.52±0.14与0.44±0.05μmol·kg⁻¹·min⁻¹（P<0.05）]。与卵泡期相比，黄体期的静息能量消耗增加（分别为218±22和199±12kJ/h）。黄体期血浆游离三碘甲状腺原氨酸（T₃）和三碘甲状腺原氨酸/反三碘甲状腺原氨酸比值（T₃/rT₃）均显著升高[T₃分别为7.7±0.6与7.1±0.8，T₃/rT₃分别为4.65±0.80与3.93±0.70（两项比较P均<0.05）]。本研究表明，女性月经周期中蛋白质代谢有微小变化，黄体期氧化亮氨酸代谢增加。循环游离T₃中观察到的伴随增加，增加了整个月经周期中蛋白质代谢和甲状腺激素波动存在因果关系的可能性。
