Electrolyte-free milk protein solution influences sodium and fluid retention in rats.
Electrolyte-free milk protein solution influences sodium and fluid retention in rats.
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DOI：
10.1017/jns.2012.24
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发表时间：
2013
影响因子：
2.5
通讯作者：
Seyama, Yousuke
中科院分区：
文献类型：
--
作者：
Ishihara, Kengo;Kato, Yoshiho;Usami, Ayako;Yamada, Mari;Yamamura, Asuka;Fushiki, Tohru;Seyama, Yousuke
牛奶是一种有效的运动后补充水分的饮料，可以保持净正液体平衡。然而，目前还不清楚是哪些组件造成了这种影响。我们评估了通过透析获得的牛奶蛋白溶液(MPS)对体液滞留的影响。给雄性Wistar大鼠在跑台运动后分别给予牛奶、MPS、牛奶电解质溶液(MES)、运动饮料和水，剂量为600ml/只。通过给药后4小时的尿量来评估总体液滞留。用~(13)C-醋酸酯示踪法测定胃排空率。用高效液相色谱法测定血浆渗透压，用渗透压测定仪测定尿钠、钾。MPS对胃排空无明显影响。在复水4h内，水、牛奶和MPS喂养大鼠的累积尿量分别为4.9亿、2.2万亿和3.4亿毫升，治疗组之间差异有统计学意义(P<0.05)。因此，MPS引起了乳汁总体液滞留的50%。MPS和牛奶喂养的大鼠的血浆醛固酮水平显著高于水喂养的大鼠。MPS喂养的大鼠血浆渗透压维持在高于水和MES喂养的大鼠的水平(P<0.05)。与饲喂MES的组相比，喂养牛奶和MPS的组的累积尿钠排泄也受到抑制。我们的结果表明，通过透析获得的MPS明显影响身体净水平衡，而不影响运动后的胃排空。这种作用归因于钠和水的滞留，以及血浆渗透压的维持。
Milk is an effective post-exercise rehydration drink that maintains the net positive fluid balance. However, it is unclear which components are responsible for this effect. We assessed the effect of milk protein solution (MPS) obtained by dialysis on body fluid retention. Milk, MPS, milk electrolyte solution (MES), sports drink and water were administered to male Wistar rats at a dose of 6 ml/rat after treadmill exercise. Total body fluid retention was assessed by urine volume 4 h after administration of hydrating liquids. The rate of gastric emptying was evaluated by a tracer method using 13C-labelled acetate. Plasma osmolality, Na and K levels, and urinary Na and K were measured by HPLC and osmometry, respectively. The gastric emptying rate was not delayed by MPS. During 4 h of rehydration, cumulative urine volumes differed significantly between treatment groups (P < 0·05) with 4·9, 2·2 and 3·4 ml from water-, milk- and MPS-fed rats, respectively. Thus, MPS elicited 50 % of the total body fluid retention of milk. Plasma aldosterone levels were significantly higher in MPS- and milk-fed rats compared with water-fed rats. Plasma osmolality was maintained at higher levels in MPS-fed rats than in water- and MES-fed rats (P < 0·05). Cumulative urine Na excretion was also suppressed in the milk- and MPS-fed groups compared with the MES-fed group. Our results demonstrate that MPS obtained by dialysis clearly affects net body water balance without affecting gastric emptying after exercise. This effect was attributed to retention of Na and water, and maintenance of plasma osmolality.