ABSTRACT
The interrenal tissue of the adrenal glands originates at stages 42 and 43, in the form of a moderate cell proliferation of the dorsal root of the dorsal mesentery. This proliferation extends longitudinally from a level slightly anterior to the coeliaco-mesenteric artery, to the caudal end of the mesonephric blastemata. Potential chromaffin cells migrate from the sympathetic ganglia area; they invade the interrenal masses from their medial side, thus completing the formation of the adrenal gland primordium. From stage 51 to 56, the cell masses of the adrenal glands are displaced along the medial face of the mesonephric kidneys. From stage 57 to 66, the adrenal glands acquire their definitive position on the medial and ventral face of the mesonephric kidneys; chromaffin cells are mixed with cords of interrenal cells.
