MICROSCOPY Vol.45▶No.4 2010

Absorptive Systems of the Intestine in Neonatal, Suckling and Weaning Period

Mamoru Fujita, Ryoko Baba and Nana Kumagai

Abstract: The absorptive cells of the small intestine play an important role for nutrient digestion and absorption. In mammals, structural and functional changes occur twice at birth and weaning on the digestive tract including intestine. The absorptive cells vary with age and region of the intestine. During neonatal-suckling period, the absorptive cells have well-developed apical and basolateral endosomal network. The network is specialized for transcytosis in jejunum, for nutrient uptake and degradation in ileum and proximal large intestine. However, the apical endosomal network gradually disappears during weaning. After weaning, the absorptive cells only have basolateral endosomal network. Here, we review our data that the endosomal network of the intestinal absorptive cells and its transition from birth to weaning, and from proximal to distal.

Key words: Intestines, Absorptive cells, Endocytosis, Transcytosis,  Endosomal network