Tulp O L
Int J Obes. 1981;5(6):579-91.
The characteristics of interscapular brown adipose tissue (IBAT) growth in normally-eating and in overnourished lean rats have been described from 3 days postweaning until 18 weeks of age. Additionally, the relationship between IBAT, diet, and body composition were investigated. The IBAT weight of normally-eating rats increased rapidly until ten weeks of age, and only gradually after that time. In overnourished rats, IBAT weight was significantly greater than in normally-eating rats after only 3 days of the over-eating regimen and increased more than twice as rapidly as in controls thereafter. Brown adipocyte diameter increased by only 30 percent in both groups during the study, while adipocyte number of overnourished rats became three-fold greater by ten weeks of age. IBAT represented 36 percent of the total brown adipose tissue in both normally-fed and in overnourished rats. Overnourished rats demonstrated a significant decrease in the efficiency of weight gain, but still became fatter than normally-fed animals. Surgical reduction of IBAT resulted in an improved efficiency of weight gain and in a greater carcass fat content in the overnourished rats, while body composition and the efficiency of weight gain were unaltered in similarly-operated normally-feeding rats. When older animals were overfed, IBAT growth was similar to that of younger rats; and, when previously overfed adult rats were returned to a stock diet for six weeks, IBAT weight was preserved. The results of these studies are consistent with the development of a nutritionally-induced hyperplasia of brown adipose tissue in the overnourished rats, similar to that which occurs in cold-adaptation, and which could enhance an animal's capacity for nonshivering thermogenesis. These data further suggest that normally-functioning brown adipose tissue may play an active role in energy expenditure in the lean rat, and thus may influence its propensity for fatness.
从断奶后3天到18周龄，已经描述了正常饮食和营养过剩的瘦大鼠肩胛间棕色脂肪组织（IBAT）生长的特征。此外，还研究了IBAT、饮食和身体组成之间的关系。正常饮食大鼠的IBAT重量在10周龄前迅速增加，之后仅逐渐增加。在营养过剩的大鼠中，在过量饮食方案实施仅3天后，IBAT重量就显著高于正常饮食大鼠，此后其增加速度比对照组快两倍多。在研究期间，两组的棕色脂肪细胞直径仅增加了30%，而营养过剩大鼠的脂肪细胞数量到10周龄时增加到三倍。在正常喂养和营养过剩的大鼠中，IBAT均占棕色脂肪组织总量的36%。营养过剩的大鼠体重增加效率显著降低，但仍比正常喂养的动物更胖。对营养过剩大鼠进行IBAT手术切除后，其体重增加效率提高，胴体脂肪含量增加，而对同样进行手术的正常喂养大鼠，其身体组成和体重增加效率未改变。当老年动物过度喂养时，IBAT的生长与年轻大鼠相似；而且，当先前过度喂养的成年大鼠恢复常规饮食六周后，IBAT重量得以维持。这些研究结果与营养诱导的营养过剩大鼠棕色脂肪组织增生的发展一致，类似于在冷适应中发生的情况，并且这可能增强动物的非颤抖产热能力。这些数据进一步表明，正常功能的棕色脂肪组织可能在瘦大鼠的能量消耗中发挥积极作用，因此可能影响其肥胖倾向。
