Ng L L, Hockaday T D
Clin Endocrinol (Oxf). 1986 Oct;25(4):383-92. doi: 10.1111/j.1365-2265.1986.tb01704.x.
Leucocyte ouabain-sensitive 22Na+ efflux was studied in 35 normal and 12 obese subjects. This efflux rate constant was raised in the obese (2.72 +/- SEM 0.13 vs 2.31 +/- 0.08 h-1, P less than 0.006), indicating a higher activity of the sodium pump in vivo, There was a significant correlation between this efflux rate constant and fasting insulin level in both the whole population and in the normals alone (rs = 0.36, P less than 0.007, and rs = 0.40, P less than 0.009 respectively). A hyperinsulinaemic-euglycaemic clamp was performed on seven normal volunteers. After 2 h, there was a significant stimulation of the leucocyte efflux rate constant (from 2.86 +/- 0.17 to 3.33 +/- 0.18 h-1, P less than 0.01). In-vitro incubation of leucocytes with insulin produced a maximal stimulation of the Na+-K+-ATPase activity of about 35% at 2 h with half-maximal stimulation achieved at 46 mU/l. Insulin (100 mU/l) also stimulated the leucocyte ouabain-sensitive 22Na+ efflux rate constant in vitro by about 11% with or without 1 h of preincubation with the insulin. These findings may explain the hypokalaemic and sodium retaining effects of insulin in man; they may also partially explain the raised Na+ efflux rate constants in obesity.
对35名正常人和12名肥胖受试者的白细胞哇巴因敏感的22Na+外流进行了研究。肥胖者的这种外流速率常数升高（2.72±标准误0.13对2.31±0.08 h-1，P<0.006），表明体内钠泵活性较高。在整个人群和仅正常人中，这种外流速率常数与空腹胰岛素水平之间均存在显著相关性（rs分别为0.36，P<0.007和rs为0.40，P<0.009）。对7名正常志愿者进行了高胰岛素-正常血糖钳夹试验。2小时后，白细胞外流速率常数有显著刺激（从2.86±0.17至3.33±0.18 h-1，P<0.01）。白细胞与胰岛素在体外孵育2小时时，Na+-K+-ATP酶活性最大刺激约35%，在46 mU/l时达到半数最大刺激。胰岛素（100 mU/l）在体外也能刺激白细胞哇巴因敏感的22Na+外流速率常数，无论是否与胰岛素预孵育1小时，刺激约11%。这些发现可能解释了胰岛素在人体中的低钾和保钠作用；它们也可能部分解释了肥胖者中升高的Na+外流速率常数。
