Hood R L, Allen C E
J Lipid Res. 1977 May;18(3):275-84.
Adipose tissue, from two depots in pigs of three breeding groups with different propensities to fatten, was characterized in terms of weight of the adipose tissue organ, adipose cell number, and mean cell volume as determined by electronic counting of adipose cells fixed with osmium tetroxide. Perirenal and extramuscular adipose tissue growth was accompanied by progressive adipose cell enlargement along with an increase in cell number. By approximately 18-20 weeks of life, adipose tissue growth in both lean Hampshire x Yorkshire and fat Minnesota 3 x 1 pigs occurred exclusively by cellular hypertrophy. By 24 weeks of life (37 kg), hyperplasia was complete in Hormel Miniature pigs, which contained about one-third as many extramuscular adipose cells as the conventional pigs. Adiposity in the pig was due to cellular hypertrophy rather than cellular hyperplasia, since during growth, the leaner conventional pigs (30.6% extramuscular fat) contained more adipose cells than the fatter pigs (46.6% extramuscular fat). The number of adipose cells per animal or per adipose organ was directly related to the true body size (weight of fat-free carcass) of the animal. Fat Minnesota 3 x 1 pigs had fewer adipose cells than lean Hampshire x Yorkshire pigs at an equivalent live weight due to the smaller true body size of these animals. In young animals (28 and 54 kg), growth rate was positively correlated with adipose cell number. However, growth rate was unrelated to the total number of cells in the more mature animals (83 and 109 kg). Therefore a slow, normal growth rate may delay but not alter the final cell number.
对来自三个具有不同育肥倾向的猪种的两个脂肪库的脂肪组织，根据脂肪组织器官的重量、脂肪细胞数量以及通过对用四氧化锇固定的脂肪细胞进行电子计数所确定的平均细胞体积进行了表征。肾周和肌外脂肪组织的生长伴随着脂肪细胞的逐渐增大以及细胞数量的增加。在大约18 - 20周龄时，瘦肉型汉普夏×约克夏猪和脂肪型明尼苏达3×1猪的脂肪组织生长仅通过细胞肥大进行。到24周龄（37千克）时，荷美尔小型猪的细胞增生已完成，其肌外脂肪细胞数量约为传统猪的三分之一。猪的肥胖是由于细胞肥大而非细胞增生，因为在生长过程中，较瘦的传统猪（肌外脂肪30.6%）比较胖的猪（肌外脂肪46.6%）含有更多的脂肪细胞。每只动物或每个脂肪器官的脂肪细胞数量与动物的真实体型（去脂胴体重量）直接相关。在相同活重下，脂肪型明尼苏达3×1猪的脂肪细胞比瘦肉型汉普夏×约克夏猪少，因为这些动物的真实体型较小。在幼龄动物（28千克和54千克）中，生长速率与脂肪细胞数量呈正相关。然而，在较成熟的动物（83千克和109千克）中，生长速率与细胞总数无关。因此，缓慢、正常的生长速率可能会延迟但不会改变最终的细胞数量。
