INTIMATE CONTACT OF CHROMAFFIN AND CORTICAL-CELLS WITHIN THE HUMAN ADRENAL-GLAND FORMS THE CELLULAR BASIS FOR IMPORTANT INTRAADRENAL INTERACTIONS

A new role for the adrenal medulla as a regulator of adrenocortical fu nction has been postulated. However, there has been no idea as to how such a cellular interaction within the human adrenal gland could take place. In this study we were able to demonstrate with the help of spec ific immunostaining of cortical and chromaffin cells, respectively, th at the two endocrine systems are interwoven with each other to an asto nishing degree. Protrusions, clusters, islets, and single cortical cel ls were made visible by immunostaining with an antibody against 17 alp ha-hydroxylase cytochrome P450 enzyme. They occurred diffusely within the entire adrenal medulla, providing ample contact zones for paracrin e interactions. Specific immunostaining for the neuroendocrine protein chromogranin-A identified the occurrence of chromaffin cells within a ll three zones of the human adrenal cortex, including the tons glomeru losa. In an ultrastructural analysis, cortical and chromaffin cells we re found in all zones in direct apposition, providing the possibility for direct intercellular exchange. The close morphological colocalizat ion of cortical and chromaffin cells revealed in this study may consti tute the basis for the growing evidence of relevant intraadrenal parac rine mechanisms within the human adrenal gland.