Krieger I, Taqi Q
Pediatr Res. 1977 Jul;11(7):796-802. doi: 10.1203/00006450-197707000-00003.
In order to manipulate cell size and cell number, rats were subjected to nutrient restriction either prenatally and until weaning at 3 weeks (group I), or from 3 until 10 weeks (group II). Body weights of group I rats were 30% of normal at the height of deprivation at 3 weeks. By 16 weeks of age maximum weights were reached, which remained subnormal in the majority; by 26 weeks only one of six had attained a normal weight. Body weights of group II were 27% of normal at the height of deprivation at 10 weeks; subsequently, only one of six did not recover. The weight, protein, and DNA content of liver, kidney, and heart were significantly decreased. The combined weight and protein content of the three organs was 30% of normal in group I and 25% of normal in group II; the DNA content of the three organs was 57% and 38% of normal in group I and group II, respectively. The greater deficit in weight than DNA content, and the mean protein/DNA ratios reflect a decrease in cell size (or increase in the cell density) of the three organs, which was greater in group I (60%) than group II (71%). Muscle cell density was increased in group I, but not in group II. At 16 weeks of age all parameters were similar in the two experimental groups (ranging from 68% to 82% or normal). Organ weight, protein, and DNA content remained deficient only in group I; these values were 74%, 70%, and 77% of normal, respectively, at 32 weeks. The deficit was proportionate to the deficit in body weight. The basal metabolic rate was measured 17-20 hr after food removal (BMR) on the day the animals were killed. In group I and II correlations between the BMR and four parameters of body composition were linear during a 4-period at the height of deprivation. Comparison of means from the regressions showed no difference between group I and II, or between these groups and normal controls with regard to the BMR per body weight, organ weight, and organ protein. The BMR per mg DNA was lower in group I and II than in normal control rats (P less than 0.05). The BMR of normal rats age 3-32 weeks showed a curvilinear correlation with body weight (BWt), BMR = 1.24 BWt0.583; organ weight (OWt), BMR = 4.30 OWt0.766; and organ protein (OPr), BMR = 4.30 OPr0.604. By contrast, the regression on DNA was linear (BMR = 7.97 + 0.449), although marked changes in body composition occurred between 3 and 32 weeks.
为了控制细胞大小和细胞数量，将大鼠分为两组进行营养限制：第一组从产前开始，持续到3周龄断奶；第二组从3周龄到10周龄。第一组大鼠在3周龄营养剥夺最严重时体重仅为正常水平的30%。到16周龄时达到最大体重，但大多数仍低于正常水平；到26周龄时，六只大鼠中只有一只体重恢复正常。第二组大鼠在10周龄营养剥夺最严重时体重为正常水平的27%；随后，六只大鼠中只有一只未恢复。肝、肾和心脏的重量、蛋白质含量和DNA含量均显著降低。第一组三个器官的总重量和蛋白质含量为正常水平的30%，第二组为25%；第一组和第二组三个器官的DNA含量分别为正常水平的57%和38%。重量方面的亏缺大于DNA含量，平均蛋白质/DNA比值反映出这三个器官的细胞大小减小（或细胞密度增加），第一组（60%）比第二组（71%）更明显。第一组肌肉细胞密度增加，第二组则没有。16周龄时，两个实验组的所有参数相似（范围为正常水平的68%至82%）。仅第一组的器官重量、蛋白质和DNA含量仍低于正常水平；在32周龄时，这些值分别为正常水平的74%、70%和77%。这种亏缺与体重亏缺成比例。在处死动物当天，禁食17 - 20小时后测量基础代谢率（BMR）。在营养剥夺最严重的4周期间，第一组和第二组的BMR与身体组成的四个参数之间呈线性相关。对回归均值的比较表明，在每体重基础上的BMR、器官重量和器官蛋白质方面，第一组和第二组之间以及与正常对照组之间均无差异。第一组和第二组每毫克DNA的BMR低于正常对照大鼠（P < 0.05）。3 - 32周龄正常大鼠的BMR与体重（BWt）呈曲线相关，BMR = 1.24 BWt0.583；与器官重量（OWt）呈曲线相关，BMR = 4.30 OWt0.766；与器官蛋白质（OPr）呈曲线相关，BMR = 4.30 OPr0.604。相比之下，尽管3至32周期间身体组成发生了显著变化，但与DNA的回归呈线性（BMR = 7.97 + 0.449）。
