Matsuo Y, Inoue F, Yoshioka H, Kinugasa A, Uchiyama M, Sawada T
Department of Pediatrics, Kyoto Prefectural University of Medicine, Japan.
Early Hum Dev. 1995 Aug 30;43(1):59-69. doi: 10.1016/0378-3782(95)01665-p.
Erythrocyte ouabain maximum binding (Vmax level) represents the number of molecules of Na-K ATPase on the erythrocyte membrane. Erythrocyte Vmax levels and sodium potassium concentrations were studied in 38 mature and 57 premature infants, including 40 very low birth weight infants, 41 children and 16 adults, in order to clarify the development of erythrocyte Na-K ATPase related to mineral balance and thermogenesis. Vmax levels were the highest (22.9 +/- 8.9 nmol/l cells) for premature infants; correlated negatively with gestational age (r = -0.77, P < 0.01). Vmax levels correlated positively with the ratio of erythrocyte potassium to sodium concentration (IC-K/Na) at < 20 nmol/l cells of Vmax levels (r = 0.72, P < 0.01), but not at > or = 20 nmol/l cells (r = 0.23). Vmax levels in very low birth weight infants, especially < 28 weeks postconception, decreased gradually with postnatal days. Ln(Vmax) levels correlated negatively with postconceptional age (r = -0.75, P < 0.01). Under 28 weeks postconception, Vmax levels were high, but not correlated with IC-K/Na. It is probable that individual Na-K ATPase molecules may be less active, and the large numbers of Na-K ATPase molecules may compensate for the individual lower activity.
红细胞哇巴因最大结合量（Vmax水平）代表红细胞膜上钠钾ATP酶的分子数量。对38名足月儿和57名早产儿（包括40名极低出生体重儿）、41名儿童和16名成人的红细胞Vmax水平及钠钾浓度进行了研究，以阐明与矿物质平衡和产热相关的红细胞钠钾ATP酶的发育情况。早产儿的Vmax水平最高（22.9±8.9 nmol/升细胞）；与胎龄呈负相关（r = -0.77，P < 0.01）。当Vmax水平<20 nmol/升细胞时，Vmax水平与红细胞钾钠浓度比（IC-K/Na）呈正相关（r = 0.72，P < 0.01），但当Vmax水平≥20 nmol/升细胞时则无相关性（r = 0.23）。极低出生体重儿，尤其是孕龄<28周者，其Vmax水平随出生后天数逐渐下降。Ln(Vmax)水平与孕龄呈负相关（r = -0.75，P < 0.01）。孕龄28周以下时，Vmax水平较高，但与IC-K/Na无相关性。单个钠钾ATP酶分子的活性可能较低，大量的钠钾ATP酶分子可能会弥补个体较低的活性。
