Estimation of endogenous adrenocorticotropin half-life using pulsatility patterns: a physiological approach to the evaluation of secretory episodes.
Estimation of endogenous adrenocorticotropin half-life using pulsatility patterns: a physiological approach to the evaluation of secretory episodes.
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使用搏动模式估计内源性促肾上腺皮质激素半衰期：评估分泌发作的生理方法。
作者：
F. López;A. Negro
一些研究表明，不同物种的ACTH消失速度非常快。然而，在大多数情况下，这些估计值的获得条件可以被视为非生理性的。本研究旨在评价生理条件下大鼠内源性ACTH的半衰期，即通过留置静脉插管连续流血的的清醒自由活动动物。每隔1分钟采血一次，可以详细描述ACTH脉动模式。每个分泌期的分析表明，许多脉冲可用于半衰期测定，只要脉冲的下行阶段由三个或更多个直线衰减点组成。在对数值进行对数转换后，通过线性回归分析下降斜率，以确定哪些斜率显示显著负相关。根据这些数值计算半衰期估计值（分钟）。这些研究使用了两组动物。在一组中，血液被连续移除而不进行置换。在这些动物中，由于出血效应，ACTH水平逐渐升高，尽管分泌继续呈脉冲状。在第二组中，通过股静脉以相同的速度抽取血液，并且ACTH水平在整个实验中保持恒定。结果表明，平均ACTH半衰期分别为5.94和7.06分钟的血液置换组，没有和。两组间差异无统计学意义。对计算出的半衰期的频率分布进行分析表明，可以将两个群体分开，一个是快速（衰变小于8分钟），另一个是慢速（衰变大于8分钟）。根据半衰期，不到一半的分泌期显示出衰减。这一观察结果表明，一些分泌事件包括分泌活动的爆发，随后是分泌基本关闭的时期。在这些条件下，衰变对应于激素的半衰期。其他发作显示延长的分泌活动，如较慢的非线性衰减所示。这些观察结果表明，ACTH的半衰期可能会有所不同，从一个情节到另一个，和不同类型的分泌事件记录可能反映了多因素控制下丘脑的ACTH分泌。
Several studies indicate that the disappearance rate of ACTH in different species is very rapid. The conditions under which these estimates were obtained, however, can be regarded in most cases as nonphysiological. The present studies were designed to evaluate the half-life of endogenous ACTH in rats under physiological conditions, i.e. awaken freely moving animals that were bled continuously through an indwelling iv cannula. Blood sampling at 1-min intervals allowed the detailed characterization of the ACTH pulsatile pattern. Analysis of each secretory episode indicated that many of the pulses could be used for half-life determinations, provided that the down phase of the pulse consisted of three or more points decaying in a straight line. After logarithmic transformation of the values, the declining slopes were analyzed by linear regression to determine which slopes showed a significant negative correlation. From those values the half-life estimates, in minutes, were calculated. Two groups of animals were used for these studies. In one group, blood was removed continuously without replacement. In these animals, ACTH levels rose progressively due to the hemorrhage effect, although secretion continued to be pulsatile. In a second group, blood was replaced at the same rate of withdrawal through a femoral vein, and ACTH levels remained constant throughout the experiment. The results indicate that the average ACTH half-life was 5.94 and 7.06 min for the groups without and with blood replacement, respectively. The differences between the two groups were not significant. Analysis of the frequency distribution of the calculated half-lives indicates that two populations can be separated, a fast (decays less than 8 min) and a slow one (decays greater than 8 min). Less than half of the secretory episodes showed a decay according to the half-life. This observation indicates that some secretory episodes consist of a burst of secretory activity followed by a period during which secretion is essentially turned off. Under these conditions, decays correspond to the half-life of the hormone. Other episodes show protracted secretory activity, as indicated by the slower, nonlinear decay. These observations suggest that half-life of ACTH may vary from one episode to another, and that the different types of secretory episodes recorded may reflect the multifactorial control of ACTH secretion by the hypothalamus.
微灌注系统中分散的大鼠垂体前叶细胞分泌促肾上腺皮质激素的详细动力学分析：绵羊促肾上腺皮质激素释放因子和精氨酸加压素的作用。
影响因子：
4.8
作者：
Watanabe,T;Orth,DN
通讯作者：
Orth,DN
未提取的人血浆中促肾上腺皮质激素的快速放射免疫测定。
影响因子：
9.3
作者：
Nicholson,WE;Davis,DR;Sherrell,BJ;Orth,DN
通讯作者：
Orth,DN
影响因子：
4.8
作者：
Lilly,MP;Engeland,WC;Gann,DS
通讯作者：
Gann,DS