Bányász T, Kovács T
Department of Physiology, University Medical School of Debrecen, Hungary.
Clin Physiol. 1996 Nov;16(6):609-20. doi: 10.1111/j.1475-097x.1996.tb00738.x.
The aim of this study was to determine the ouabain receptor density, sodium content and contractile properties of skeletal muscles in rats with insulin-dependent (IDDM) and non-insulin-dependent (NIDDM) diabetes mellitus induced by streptozotocin treatment. These parameters were compared in isolated soleus (SOL) and extensor digitorum longus (EDL) muscles of diabetic animals and their age-matched controls. Reversibility of the diabetes-induced changes was studied by insulin or thyroxine substitution. In IDDM SOL muscles both the maximum [3H]ouabain binding capacity (Bmax) and dissociation constant (Kd) were decreased, the sodium content of the muscles increased and the velocity of contraction and relaxation decreased. Similar changes (except for the reduction of Bmax) were observed in diabetic EDL muscles; however, in this case these differences were less prominent. All of these changes were reversed by insulin substitution, whereas thyroxine treatment normalized only the changes in Bmax and velocity of contraction. In contrast to the changes observed in IDDM, NIDDM increased both Kd and Bmax values. Linear correlation was observed between the velocity of contraction or relaxation and the density of [3H]ouabain binding sites in the SOL muscles of IDDM rats. It is concluded that IDDM and NIDDM induce opposite alterations in the density and ouabain sensitivity of the Na(+)-K+ pump in rat skeletal muscle. These diabetic changes are fully reversible with insulin substitution, they are variable in size according to the type of muscle, and are also reflected in the sodium content and, ultimately, in the contractile parameters of the muscles.
本研究的目的是测定经链脲佐菌素处理诱导的胰岛素依赖型（IDDM）和非胰岛素依赖型（NIDDM）糖尿病大鼠骨骼肌的哇巴因受体密度、钠含量及收缩特性。将糖尿病动物及其年龄匹配的对照动物的离体比目鱼肌（SOL）和趾长伸肌（EDL）的这些参数进行比较。通过胰岛素或甲状腺素替代研究糖尿病诱导变化的可逆性。在IDDM的SOL肌中，最大[3H]哇巴因结合容量（Bmax）和解离常数（Kd）均降低，肌肉钠含量增加，收缩和舒张速度降低。在糖尿病EDL肌中观察到类似变化（除Bmax降低外）；然而，在这种情况下这些差异不太明显。所有这些变化都可通过胰岛素替代逆转，而甲状腺素治疗仅使Bmax和收缩速度的变化恢复正常。与IDDM中观察到的变化相反，NIDDM使Kd和Bmax值均升高。在IDDM大鼠的SOL肌中，观察到收缩或舒张速度与[3H]哇巴因结合位点密度之间存在线性相关性。结论是，IDDM和NIDDM在大鼠骨骼肌中诱导Na(+)-K+泵密度和哇巴因敏感性发生相反改变。这些糖尿病性变化可通过胰岛素替代完全逆转，其大小因肌肉类型而异，并且也反映在肌肉的钠含量以及最终的收缩参数中。
