The maturation of cortisone-treated embryonic duodenum in vitro. I. The villus.
نویسنده
چکیده
M I T O T I C expansion of the mucosa coupled with contraction of intrinsic longitudinal and circular muscle fibers produces previllous ridges on the luminal surface of the embryonic chick duodenum by the thirteenth day of incubation. Subsequently, remodelling by periodic indentation of the mucosal surface yields primitive villi which expand and elongate to form the tall, finger-like projections characterizing the absorptive surface of the mature duodenum (Hilton, 1902; Pap, 1933; Coulombre & Coulombre, 1958). Coincident with the morphogenesis of the villus is the acquisition of enzymatic activity in its epithelium. As early as the 14th day of incubation of the chick embryo, alkaline phosphatase is detectable in the epithelial free border of the duodenum (Hancox & Hyslop, 1954), although other investigators report later appearances for this enzyme (Moog, 1950; Hebert, 1950). The onset of this physiological activity in the duodenal epithelium may be accelerated by exposure to adrenocorticoids as originally postulated by Hebert (1950). Administration of these hormones in vivo or in vitro induces precocious enzyme activity (Moog et al. 1954, 1955, 1957, 1962). In this investigation, the maturation of the intestinal villus has been studied in vitro to ascertain the effects of cortisone acetate upon the morphological aspects of differentiation. Alkaline phosphatase activity has been used as a marker for functional maturation since this is known to be influenced by hormone treatment. It follows that if the morphological and physiological phases of the differentiative process were linked in any way, stimulation of the one with cortisone should produce coincident stimulation of the other.
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عنوان ژورنال:
- Journal of embryology and experimental morphology
دوره 14 2 شماره
صفحات -
تاریخ انتشار 1965