Active cell movements and embryonic cholinesterase in the postmetamorphic completion of the adrenal morphogenesis in frogs

The adrenal gland in Rana esculenta complex, as in other advanced anurans, is not yet in its definitive position at the end of the metamorphosis and reaches it subsequently, before sexual maturity. The displacement takes place by various means, among which active cellular movements prevail. These are demonstrated by the presence of acetylcholinesterase (AChE) in noninnervated cells (embryonic AChE). The disintegration of the connective tissues which delimit the cords of the adrenal gland, the passive transport of cells by the blood vessels and the movements of adjacent renal and mesenchymal cells collaborate with the active movements of the adrenal cells.