Application of steady state kinetics to the estimation of synthesis rate and turnover time of tissue catecholamines.
Application of steady state kinetics to the estimation of synthesis rate and turnover time of tissue catecholamines.
复制标题
稳态动力学在估计组织儿茶酚胺的合成速率和周转时间中的应用。
DOI：
--
复制
发表时间：
1966
影响因子：
3.5
通讯作者：
H. Smookler
中科院分区：
文献类型：
--
作者：
B. Brodie;E. Costa;A. Dlabač;N. Neff;H. Smookler
测量各种组织中儿茶酚胺合成速率的方法利用了稳态关系，其中儿茶酚胺形成速率等于流出速率。用α-甲基酪氨酸阻断酪氨酸羟化酶后，大鼠和家兔脑内去甲肾上腺素（NE）、多巴胺及外周各组织NE水平均呈指数下降。从胺下降的速率常数和正常的儿茶酚胺水平的乘积计算出儿茶酚胺的合成速率。用这种方法得到的心脏NE值与用d1-H3-NE标记后放射性下降得到的值几乎相同。该方法在大鼠研究中的应用表明，NE在心脏、唾液腺和虹膜中的周转时间约为12小时，而脑NE为6小时，脑多巴胺为3小时，颈交感神经节中NE为2小时。在兔子下丘脑中，NE的形成速度比中脑快5倍，尽管周转时间几乎相同。这表明，每个肾上腺素能单位的合成速率可能是相似的，不同脑区合成速率的变化是每克组织中神经元数量的函数。
A method of measuring the rate of synthesis of catecholamines in various tissues takes advantage of the steady state relationship in which the rate of catecholamine formation is equal to the rate of efflux. After tyrosine hydroxylase is blocked with α-methyltyrosine, the brain levels of norepinephrine (NE) and dopamine and the NE levels in various peripheral tissues of rats and rabbits decline exponentially. The rate of synthesis of the catecholamines is calculated from the product of the rate constant of amine decline and the normal catecholamine level. The value for heart NE yielded by this method is almost identical with that obtained from the decline in radioactivity after labeling with dl -H3-NE. The application of this method to studies in the rat shows that the turnover time for NE in heart, salivary gland and iris is about 12 hr, compared to 6 hr for brain NE, 3 hr for brain dopamine and 2 hr for NE in the cervical sympathetic ganglia. In the rabbit hypothalamus, NE is formed five times more rapidly than in the midbrain, though the turnover times are almost identical. This suggests that the rate of synthesis might be similar in each adrenergic unit and that variations in rates of synthesis in different brain areas are a function of the number of neurons per gram of tissue.