MORPHOLOGICAL AND FUNCTIONAL-STUDIES OF THE PARACRINE INTERACTION BETWEEN CORTEX AND MEDULLA IN THE ADRENAL-GLAND

Within the last years it has become evident that besides the hypothala mo-pituitary-adrenal axis, extrapituitary mechanisms exist that regula te the activity of the adrenal cortex. In this context, intra-adrenal regulatory mechanisms play an important role. Several secretory produc ts from adrenomedullary cells are able to influence adrenocortical ste roidogenesis. Since the main blood flow within the adrenal is directed centripetally from the cortex to the medulla, chromaffin cells should act on cortical cells in a paracrine manner. The morphological prereq uisite for this regulatory pathway is seen in the close apposition of the two tissues. within the mammalian adrenal, the two endocrine tissu es are interwoven to an astonishing degree with cortical cells located within the medulla and vice versa. It is concluded from morphological and functional studies that paracrine interactions between cortex and medulla play an important role in the regulation of adrenocortical st eroidogenesis. (C) 1997 Wiley-Liss, Inc.