Effect of Food Restriction on Biorhythm

研究了食物限制对生物节律的影响。以钙激活蛋白水解酶(CAF)及其内源性抑制物(CAF抑制物)活性为指标，研究了食品最大限量--储藏条件下生物节律的变化。用从RAR骨骼肌获得的粗制CAF制剂，也研究了CAF对饥饿反应的钙敏感性的变化。饥饿组大鼠背部最长肌中总CaF活性显著高于喂食组(p&lt；0.01)。另一方面，CaF抑制剂活性在实验期间变化不大。因此，CAF可能在饥饿引起的肌原纤维蛋白降解中起重要作用。对照组和饥饿1d组大鼠在钙离子浓度<1 mM时几乎检测不到粗酶活性，而饥饿2d以上组钙离子浓度低于1 mM组大鼠CaF制剂被充分激活。这些结果表明，在饥饿过程中，活体细胞中可能存在高需钙CaF(H-CAF)向低需钙CaF(L-CAF)的转化或L-CAF的特异性诱导。

Effect of food restriction on biorhythm was studied. Calcium activated protease(CAF) and its endogeneous inhibitor(CAF inhibitor) activities were used as the indexes of biorhythm changes under stavation, the maximum restriction of food. The changes in calcium sensitivity of CAF in response to starvation were also studied using crude CAF preparations obtained from the skeletal muscle of rars. Total CAF activity in longissimus muscle of back of starved rats significantly increased in comparison with that of fed rats (p<0.01). On the other hand, CAF inhibitor activity had little changed during experimental period. It is therefore suggested that CAF might take an important role in myofibrillar protein degradation in response to starvation. Crude CAF activity was hardly detected in the calcium concentration less than 1 mM in the control group and in the 1 day-starved group rats, however CAF preparation was sufficiently activated in calcium less than 1mM in the groups starved for more 2 days. These results indicate the possibility of the transformation of high calcium required form of CAF (H-CAF) into low calcium required form of CAF (L-CAF) or the specific induction of L-CAF in the living cells during starvation.