Intraadrenal interactions in the regulation of adrenocortical steroidogenesis

Journal/Book: Z Rheumatol 1999; 58: 295. 1999;

Abstract: St. R. Bornstein; Developmental Endocrinology Branch National Institute of Child Health and Human Development NIH Clinical Center Bethesda Maryland The autonomic nervous system and the hypothalamicpituitary-adrenal (HPA) axis both play a central role in the regulation of a wide range of physiological processes and are substantially involved in the maintenance of homeostasis and the adaption of the organism to stressful conditions. The appropriate functioning of the systems to meet this demand largely depends on the intact and finely tuned regulatory mechanisms which act on several levels. The adrenal gland combines essential components of the autonomic nervous system and the HPA axis in close contact. From morphological immunohistochemical and ultrastructural studies it became evident that the chromaffin cells of the adrenal medulla and the steroid producing cortical cells are extensively intermingled which is in contrast to previous contentions regarding the adrenal medulla and cortex as two distinct tissues with respect to location and function. In in vitro studies a variety of regulatory factors produced and released by the adrenal medulla have been identified as playing an important role in modulating adrenocortical function. An adrenocortical cell deprived of its tissue integrity of input from the nervous system and of ist intercellular communication with chromaffin vascular and immune cells loses its normal capacity to produce glucocorticoids and adequately respond to the homeostatic challanges of stress. Animal models of overexpression and depletion in catecholaminergic enzymes as well as of alterated function of components of HPA axis provide evidence that the mutual interdependence of sympatho - adrenal system and HPA axis at the level of the adrenal gland is functional and of physiological relevance in vivo and that this relationship may als be involved in the pathophysiology of adrenal disease. ... le

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