Zorbas Yan G, Kakuris Kostas K, Charapakhin Kyrill P, Afoninos Andreas B
Higher Institute of Biochemistry, Gomel, Belarus.
Int J Med Sci. 2005;2(3):107-13. doi: 10.7150/ijms.2.107. Epub 2005 Jul 1.
The aim of this study was to determine that hypokinesia (restricted motor activity) could increase potassium (K+) losses with decreased tissue K+ content showing decreased K+ deposition. To this end, measurements were made of K+absorption, tissue K+ content, plasma K+ levels, fecal and urinary K+ excretion during and after hypokinesia (HK) with and without K+ supplementation. Studies conducted on male Wistar rats during a pre-hypokinetic period, a hypokinetic period and a post-hypokinetic period. Rats were equally divided into four groups: unsupplemented vivarium control rats (UVCR), unsupplemented hypokinetic rats (UHKR), supplemented vivarium control rats (SVCR) and supplemented hypokinetic rats (SHKR). SHKR and UHKR were kept in small individual cages which restricted their movements in all directions without hindering food and water consumption. SVCR and UVCR were housed in individual cages under vivarium control conditions. SVCR and SHKR consume daily 3.96 mEq potassium chloride (KCl) per day. Absorption of K+, and K+ levels in bone, muscle, plasma, urine and feces and PA levels did not change in SVCR and UVCR compared with their pre-HK levels. During HK, plasma, fecal and urinary K+ levels and plasma aldosterone (PA) levels increased significantly (p<0.05) with time, while K+ absorption, muscle and bone K+ content decreased significantly (p<0.05) with time in SHKR and UHKR compared with their pre-HK values and the values in their respective vivarium controls (SVCR and UVCR). During the initial 9-days of post-HK, K+ absorption increased significantly (p<0.05) and plasma K+ levels, fecal and urinary K+ losses and PA levels decreased significantly (p<0.05) and muscle and bone K+ content remained significantly (p<0.05) depressed in SHKR and UHKR compared with their pre-HK and their respective vivarium control values. During HK and post-HK periods, K+ absorption, bone and muscle K+ content, and K+ levels in plasma, urine and feces and PA levels were affected significantly (p<0.05) more in SHKR than in UHKR. By the 15th day of post-HK the values in SHKR and UHKR approach the control values. The higher K+ losses during HK with decreased tissue K+ levels shows decreased K+ deposition. The higher K+ loss with lower tissue K+ levels in SHKR than in UHKR shows that K+ deposition decreases more with K+ supplementation than without. Because SHKR had shown lower tissue K+ content and lost higher K+ amounts than UHKR it was concluded that the risk of decreased K+ deposition and tissue K+ depletion is inversely related to K+ intake, i.e., the higher K+ intake, the greater the risk for decreased K+ deposition, and the higher K+ losses and the greater the risk for tissue K+ depletion. The dissociation between tissue K+ depletion and K+ excretion indicates decreased K+ deposition as the principal mechanism of tissue K+ depletion during prolonged HK.
本研究的目的是确定运动功能减退（运动活动受限）是否会增加钾（K+）流失，同时组织K+含量降低，表明K+沉积减少。为此，在运动功能减退（HK）期间及之后，在补充和不补充K+的情况下，对K+吸收、组织K+含量、血浆K+水平、粪便和尿液中的K+排泄进行了测量。研究在雄性Wistar大鼠的运动功能减退前期、运动功能减退期和运动功能减退后期进行。大鼠被平均分为四组：未补充K+的饲养对照大鼠（UVCR）、未补充K+的运动功能减退大鼠（UHKR）、补充K+的饲养对照大鼠（SVCR）和补充K+的运动功能减退大鼠（SHKR）。SHKR和UHKR被饲养在小的单独笼子里，限制它们各个方向的活动，但不影响食物和水的摄取。SVCR和UVCR饲养在饲养对照条件下的单独笼子里。SVCR和SHKR每天消耗3.96 mEq氯化钾（KCl）。与运动功能减退前期水平相比，SVCR和UVCR中K+的吸收以及骨骼、肌肉、血浆、尿液和粪便中的K+水平及血浆醛固酮（PA）水平没有变化。在运动功能减退期间，与运动功能减退前期值及其各自的饲养对照（SVCR和UVCR）相比，SHKR和UHKR中血浆、粪便和尿液中的K+水平以及血浆醛固酮（PA）水平随时间显著增加（p<0.05），而K+吸收、肌肉和骨骼中的K+含量随时间显著降低（p<0.05）。在运动功能减退后期的最初9天，与运动功能减退前期及其各自的饲养对照值相比，SHKR和UHKR中K+吸收显著增加（p<0.05），血浆K+水平、粪便和尿液中的K+流失以及PA水平显著降低（p<0.05），肌肉和骨骼中的K+含量仍显著降低（p<0.05）。在运动功能减退期间和运动功能减退后期，SHKR中K+吸收、骨骼和肌肉中的K+含量以及血浆、尿液和粪便中的K+水平及PA水平受到的影响（p<0.05）比UHKR更显著。到运动功能减退后期第15天，SHKR和UHKR中的值接近对照值。运动功能减退期间较高的K+流失以及组织K+水平降低表明K+沉积减少。SHKR中组织K+水平较低但K+流失比UHKR更高，这表明与不补充K+相比，补充K+时K+沉积减少得更多。由于SHKR的组织K+含量低于UHKR且K+流失量更高，因此得出结论，K+沉积减少和组织K+耗竭的风险与K+摄入量呈负相关，即K+摄入量越高，K+沉积减少风险越大，K+流失越高，组织K+耗竭风险越大。组织K+耗竭与K+排泄之间的分离表明，在长时间运动功能减退期间，K+沉积减少是组织K+耗竭的主要机制。
