| Co-Investigator(Kenkyū-buntansha) |
SATO Mitsuru Akita University, Department of Anatomy, Research Associate, 医学部, 助手 (60226008)
IMAI Katsuyuki Akita University, Department of Anatomy, Research Associate, 医学部, 助手 (80006741)
SENOO Haruki Akita University, Department of Anatomy, Professor, 医学部, 教授 (90171355)
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| Research Abstract |
Male Wistar strain rats maintained on a normal chow diet were fasted for 18 h and used. Experimental animals were administered 50,000IU retinyl palmitate/0.5 ml corn oil to the stomach through a gastric tube. Three, 6, 24, 48, 96 h and 1 week after the administration of retinyl palmitate, each rat was deeply anesthetized and the stomach, duodenum, jejunum, ileum, and ascending colon were examined morphologically. Three h after the administration, autofluorescence of vitamin A was observed in the absorptive epithelial cells in the duodenum, jejunum and ileum. Six h after the administration, the autofluorescence emanated from not only the epithelial cells of the jejunum but cells in the lamina propria mucosae of the jejunum. Twenty-four, 48 and 96 h and even 1 week after the administration, the autofluorescence disappeared from the epithelial cells but remainedin the cells in the lamina propria mucosae of the jejunum. Electron microscopically, numerous pores were observed in the basement membrane beneath the epithelial cells. Fibroblast-like cells, pericytes, and macrophage-like cells in the lamina propria mucosacstored many large lipid droplets within the cytoplasm. Immunofluorescence demonstrated that the fibroblast-like cells in the lamina propna mucosae of the jejunum, ileum, and colon expressed desmin and alpha - smooth muscle actin that are specific markers for the hepatic stellate cells (vitamin A-storing cells). These data indicate that the vitamin A absorption and storage system, belonging to the extrahepatic stellate cell system, exists in the digestive tract.
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