The maturation of cortisone-treated embryonic duodenum in vitro. II. The striated border
Regulation of the morphological and physiological maturation of embryonic duodenal mucosa by adrenocorticoid hormones has been demonstrated with a variety of techniques. Single injections of cortisone acetate (Moog & Richardson, 1955; Moog & Thomas, 1957); multiple daily administrations of cortisone (Moog & Ford, 1957; Moog, 1959); or in vitro maintenance of duodenal fragments with adrenal steroids (Moog & Nehari, 1954; Moog & Kirsch, 1955) all accelerate morphogenesis and the onset of alkaline phosphatase activity in this tissue. The differentiation of the duodenal mucosa is not only responsive to hormonal application but is dependent on it. Hinni & Watterson (1963) have ablated pituitary glands from chick embryos, hence interrupting the hypophysealadrenal axis and arresting adrenal function. Following this procedure, morphogenesis is retarded and alkaline phosphatase activity in the epithelium diminished. Release from adrenocortical influence does not modify the course of differentiation, but does affect the rate of cellular maturation.