Comparative Morphological and Immunohistochemical Characteristics of the Human Fetal Organs of Zuckerkandl and Adrenal Medulla

The adrenal medulla and organs of Zuckerkandl consist of chromaffin cells that produce, store, and secrete catecholamines. In humans, the adrenal medulla is known to function throughout postnatal life, while the organs of Zuckerkandl degenerate by 2–3 years of postnatal life. Although the history of investigation of chromaffin cells goes back more than a century, little is known about the interaction of the adrenal glands and organs of Zuckerkandl in human fetal development. In the current study, we attempted to compare these two organs using serial sectioning, routine histological staining, and immunohistochemical reactions in human embryos, prefetuses, and fetuses from 8 to 26 gestational weeks. In our study, we used antibodies for tyrosine hydroxylase, dopamine beta-hydroxylase, and phenylethanolamine N-methyltransferase, which are enzymes of catecholamine synthesis, β-III tubulin, and S100. We found two morphological cell types (large and small) in the developing ganglia, organs of Zuckerkandl, and adrenal medulla and two migration patterns of large cells and small cells from the developing paraganglia to the adrenal anlage. We determined the immunohistochemical characteristics of these migrating cells. We also determined that 12 gestational weeks was the age of the first appearance of phenylethanolamine N-methyltransferase reactivity in developing chromaffin cells, which is important data in the light of the controversial glucocorticoid theory of phenylethanolamine N-methyltransferase induction in humans.