Muralidhara D V, Shetty P S
Department of Physiology, St. John's Medical College, Bangalore.
Indian J Physiol Pharmacol. 1987 Jul-Sep;31(3):149-58.
Preweaning nutritional deprivation with or without postweaning partial energy restriction produces animals of small size with defective nonshivering thermogenesis. This is also associated with their inability to tolerate cold exposure to 5 degrees C. Adequate nutritional rehabilitation for a reasonable length of time of 10 days abolishes the defect in cold induced thermogenesis (CIT) although the deficits in body weight or body size are not corrected. This may indicate that the defect may be possibly due to the non availability of enough substrates rather than to a change in the functioning of thermogenic organs such as brown adipose tissue. Sucrose feeding which enhances caloric intake and hence sympathetic activity can reverse the defect in CIT only in older rats suggesting the possibility of delayed maturation of thermoregulatory functions in young rats which are energy deprived. The results of this study possibly indicate that there may be a temporary reduction of the sympathetic nervous system activity during the period of energy restriction which compromises cold tolerance and which is reactivated rapidly following nutritional rehabilitation.
断奶前营养剥夺，无论是否伴有断奶后部分能量限制，都会产生体型小且非寒战产热有缺陷的动物。这也与它们无法耐受5摄氏度的冷暴露有关。进行为期10天的合理时长的充分营养康复，可消除冷诱导产热（CIT）缺陷，尽管体重或体型的不足并未得到纠正。这可能表明，该缺陷可能是由于没有足够的底物，而非产热器官如棕色脂肪组织的功能发生改变。蔗糖喂养可增加热量摄入，从而增强交感神经活动，仅在老年大鼠中可逆转CIT缺陷，这表明能量缺乏的幼鼠体温调节功能可能成熟延迟。本研究结果可能表明，在能量限制期间，交感神经系统活动可能会暂时降低，这会损害耐寒能力，而在营养康复后会迅速重新激活。
