SELECTIVE ACTIVATION OF NOREPINEPHRINE-SECRETING AND EPINEPHRINE-SECRETING CHROMAFFIN CELLS IN RAT ADRENAL-MEDULLA
SELECTIVE ACTIVATION OF NOREPINEPHRINE-SECRETING AND EPINEPHRINE-SECRETING CHROMAFFIN CELLS IN RAT ADRENAL-MEDULLA
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DOI：
10.1152/ajpregu.1992.263.3.r716
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发表时间：
1992-09-01
影响因子：
--
通讯作者：
KAPLAN, BB
中科院分区：
文献类型：
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作者：
VOLLMER, RR;BARUCHIN, A;KAPLAN, BB
在雄性斯普拉格 - 道利大鼠中研究了胰岛素诱导的低血糖和寒冷暴露对肾上腺髓质肾上腺素（Epi）和去甲肾上腺素（NE）细胞的不同影响。在禁食过夜的大鼠中，胰岛素导致明显的低血糖，在给予胰岛素3小时后，肾上腺髓质Epi含量降低了70%。未观察到NE含量的变化。胰岛素注射后血浆Epi浓度显著升高，NE升高幅度较小。相比之下，暴露于4℃环境选择性地降低了肾上腺NE含量，在18小时时该影响具有统计学意义。寒冷暴露还导致血浆NE显著升高，但Epi没有升高。胰岛素诱导的低血糖和寒冷暴露均显著升高肾上腺多巴胺，表明儿茶酚胺的合成受到刺激。儿茶酚胺形成增强的进一步证据是，用α - 甲基 - 对 - 酪氨酸（AMT）抑制合成极大地增强了胰岛素诱导的低血糖选择性降低肾上腺髓质Epi含量的能力。类似地，在寒冷暴露的动物中，AMT预处理加速了NE的耗竭，以至于在3小时时观察到显著下降。这些结果支持以下结论：肾上腺分泌儿茶酚胺的两种主要细胞群可能被不同的应激源优先刺激。此外，增强的合成活性有助于维持分泌Epi和NE的细胞中的儿茶酚胺储存。
The differential effects of insulin-induced hypoglycemia and cold exposure on adrenal medullary epinephrine (Epi) and norepinephrine (NE) cells were investigated in male Sprague-Dawley rats. In rats fasted overnight, insulin produced a marked hypoglycemia that resulted in a 70% decrease in adrenal medullary Epi content 3 h after the insulin was administered. No change in NE content was observed. Plasma Epi concentration was increased markedly after insulin, with a smaller increment in NE. In contrast, exposure to a 4-degrees-C environment selectively reduced adrenal NE content, with the effect reaching statistical significance at 18 h. Cold exposure also led to a significant rise in plasma NE but not Epi. Both insulin-induced hypoglycemia and cold exposure significantly elevated adrenal dopamine, indicating that catecholamine synthesis was stimulated. Further evidence of enhanced catecholamine formation was the observation that inhibition of synthesis with alpha-methyl-p-tyrosine (AMT) greatly augmented the ability of insulin-induced hypoglycemia to selectively reduce adrenal medullary Epi content. Similarly, in cold-exposed animals, AMT pretreatment accelerated the NE depletion so that a significant decline was observed at 3 h. These results support the conclusion that the two major populations of adrenal catecholamine-secreting cells may be preferentially stimulated by different stressors. Moreover, augmented synthetic activity functions to maintain catecholamine stores in both Epi- and NE-secreting cells.