The Importance of Mesenchymal Factors in the Differentiation of Chick Epidermis

Open Access
Publisher Website
Google Scholar
Abstract
That the mesenchyme may determine the differentiation of epithelial derivatives has been demonstrated in a wide range of embryonic organs, e.g. limb-bud (Zwilling, 1956; Saunders, Gasseling, & Gfeller, 1958), feather-germs (Sengel, 1956), preen gland (Gomot, 1958), salivary gland (Borghese, 1950; Grobstein, 1953), and thymus (Auerbach, 1960). These inductions probably act through various mechanisms, but a feature that is common to many of them is the relatively brief duration of the mesenchymal stimulus, e.g. the mesenchymal induction of feather-germs in the chick lasts for half a day only. This brevity of action is also characteristic of the classic inductions, e.g. of the neural plate or lens. The work reported here (and briefly elsewhere, McLoughlin 1961 a, b,) indicates that besides such brief inductions there are more prolonged epitheliomesenchymal interactions which maintain the normal growth and differentiation of tissues throughout embryonic life, and possibly in adult life also.