Pignatelli D, Magalhães M M, Magalhães M C
Institute of Histology and Embryology, Faculty of Medicine of Porto, Portugal.
Horm Metab Res. 1998 Jun-Jul;30(6-7):464-74. doi: 10.1055/s-2007-978915.
The adrenal gland plays a pivotal role in the stress response since this response involves the hypothalamic-pituitary-adrenal axis (HPAA) and the sympatho-adrenomedullary system (SAMS) as its two principal components. An important relation between the immune system and the other stress response systems is also centered on the adrenal gland. It is well known that the cortex secretes glucocorticoids while the medulla secretes epinephrine, two of the major effects of the stress response. Some other aspects, however, also deserve special consideration: The paracrine effects of the cortical secretion on the medullary cells through the special irrigation system of the gland and reciprocally the influence of the medulla upon the cortex, either by direct close contact or by local innervation. The influence of vascular events also needs to be considered as well as the existence of some local hormonal axis such as those resulting from the local production of renin or CRH in adrenal cells. Some other cells such as mast cells, macrophages and endothelial cells seem to play a role in the regulation of the adrenal cortex and hence in the tuning of the stress response. Stressors stimulate the release of CRH from the hypothalamic paraventricular nucleus inducing the secretion of ACTH from the pituitary and that of corticosteroids from the adrenal cortex. Through the activation of the sympathetic system the adrenal can be stimulated even before adequate levels of ACTH are reached. In conditions of chronic stress the adrenal cortex undergoes an adaptation that allows the hypersecretion of glucocorticoids to occur even without the increment of ACTH.
肾上腺在应激反应中起关键作用，因为这种反应涉及下丘脑 - 垂体 - 肾上腺轴（HPAA）和交感 - 肾上腺髓质系统（SAMS）这两个主要组成部分。免疫系统与其他应激反应系统之间的重要关系也以肾上腺为中心。众所周知，肾上腺皮质分泌糖皮质激素，而髓质分泌肾上腺素，这是应激反应的两个主要效应。然而，其他一些方面也值得特别考虑：皮质分泌物通过腺体的特殊灌溉系统对髓质细胞产生旁分泌作用，反之，髓质通过直接紧密接触或局部神经支配对皮质产生影响。血管事件的影响也需要考虑，以及一些局部激素轴的存在，例如肾上腺细胞中局部产生肾素或促肾上腺皮质激素释放激素（CRH）所导致的那些激素轴。一些其他细胞，如肥大细胞、巨噬细胞和内皮细胞，似乎在肾上腺皮质的调节中发挥作用，从而在应激反应的调节中发挥作用。应激源刺激下丘脑室旁核释放CRH，诱导垂体分泌促肾上腺皮质激素（ACTH）以及肾上腺皮质分泌皮质类固醇。通过交感神经系统的激活，即使在达到足够水平的ACTH之前，肾上腺也可被刺激。在慢性应激条件下，肾上腺皮质会发生适应性变化，即使在ACTH不增加的情况下也能发生糖皮质激素的过度分泌。
