Dauncey M J, Burton K A
AFRC Institute of Animal Physiology and Genetics Research, Babraham, Cambridge, Great Britain.
Pflugers Arch. 1989 Jul;414(3):317-23. doi: 10.1007/BF00584633.
The influence of environmental temperature and energy intake on 3H-ouabain binding sites in skeletal muscle has been investigated in young growing pigs at 8 weeks of age. Animals lived for several weeks at 35 or 10 degrees C on a high (H) or low (L) level of energy intake. The four treatment groups were thus: 35H, 35L, 10H and 10L. The total number of 3H-ouabain binding sites (Bmax) in longissimus dorsi muscle (mean values +/- SEM) were 221 +/- 66, 214 +/- 61, 350 +/- 76 and 486 +/- 114 pmol/g wet weight for the 35H, 35L, 10H and 10L groups respectively. Bmax was significantly greater in those living in the cold than the warm (P less than 0.001). Moreover, at 10 degrees C energy intake had a significant effect, with Bmax being greater in the 10L than the 10H group (P less than 0.005). Level of energy intake had no influence on Bmax at 35 degrees C. The apparent dissociation constant was not affected by either temperature or intake. The elevated Bmax and hence the increase in number of Na+,K+-pumping sites in the cold is probably related to increased muscular activity associated with shivering. However, thyroid status also influences the number of Na+,K+-pumping sites and this may have been a contributory factor in the present study. In addition, the elevated Bmax suggests a greater potential for non-shivering thermogenesis associated with increased Na+,K+-ATPase concentration in the cold. Differences in relative stage of development between the four groups may help to explain the results for Bmax in relation to level of energy intake.
在8周龄的幼龄生长猪中，研究了环境温度和能量摄入对骨骼肌中3H-哇巴因结合位点的影响。动物在35℃或10℃下，分别处于高（H）或低（L）能量摄入水平下生活数周。因此，四个处理组分别为：35H、35L、10H和10L。背最长肌中3H-哇巴因结合位点的总数（Bmax，平均值±标准误），35H、35L、10H和10L组分别为221±66、214±61、350±76和486±114 pmol/g湿重。生活在寒冷环境中的猪的Bmax显著高于温暖环境中的猪（P<0.001）。此外，在10℃时，能量摄入有显著影响，10L组的Bmax高于10H组（P<0.005）。在35℃时，能量摄入水平对Bmax没有影响。表观解离常数不受温度或摄入量的影响。寒冷环境中Bmax升高，因此Na+、K+-泵位点数量增加，可能与寒战相关的肌肉活动增加有关。然而，甲状腺状态也会影响Na+、K+-泵位点的数量，这可能是本研究中的一个促成因素。此外，Bmax升高表明在寒冷环境中，与Na+、K+-ATP酶浓度增加相关的非寒战产热潜力更大。四组之间相对发育阶段的差异可能有助于解释与能量摄入水平相关的Bmax结果。
