Site-oriented absorption function and its regulation mechanism

1995 Fiscal Year Final Research Report Summary

• Project/Area Number: 06660163
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: 食品科学・栄養科学
• Research Institution: Kyoto Prefectural University
• Principal Investigator: IWAMI Kimikazu Kyoto Prefectural University Department of Agricultural Chemistry, Professor, 農学部, 教授 (00026569)
• Co-Investigator(Kenkyū-buntansha): SUGIYAMA Kaoru Kyoto Prefectural University Department of Agricultural Chemistry Assistant Prof, 農学部, 助手 (30226469)
• Project Period (FY): 1994 – 1995
• Keywords: jejunoileal transposition / adaptation gut functions / hyperplasia of villi / transport system for bile acide / Na^+ / bile acid cotransporter / site-oriented gene expression

Research Abstract

Male Wistar rats which had undergone resection (R) or transposition (T) on the jejunoileum were examined for functional and morphological changes in their residual intestinal tract. Villous length and mucosal weight of doudenum, jejunum, and ileum were much more in group T than in group R.Pancreatic hypertrophy was also observed for group T.There was no significant difference between both the groups in protein/RNA ratio of mucosa as well as specific activity of brush border membrane-bound enzymes. As for a Na^+-dependent transport for bile acid (taurocholate), its transmural transport was measured using several everted sacs from the whole small intestine. As a result, sctive transport was found to occur in the very everted sac from the intrinsic distal ileum irrespective of resection or transposition. The expression experiment with Xenopus laevis oocytes revealed that the Na^+-dependent taurocholate uptake increased with increasing amounts of mucosal poly (A)^+RNA,exclusively appearing in the oocytes inclusive of ileal mRNA.Such a site-specific expression was ascertained by Northern blot analysis using a specific probe. It has become by Northern blot analysis using other probes that c-myc and IGF-1 mRNA don't emerge 2 days after operation and that neither c-fos nor ODC mRNA differs in emergence between R and T groups. Mucosal stimulation such as intraluminal food transit and enteral nutrition should be considered for a plausible explanation of unknown factors affecting ileal hyperplasia.