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标题：INTESTINAL ABSORPTION OF TETRAMETHYLAMMONIUM AND ITS DERIVATIVES IN RATS
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作者：HIDEMI TSUBAKI ; TORU KOMAI
期刊名称：Biological and Pharmaceutical Bulletin
印刷版ISSN：0918-6158
电子版ISSN：1347-5215
出版年度：1986
卷号：9
期号：9
页码：747-754
DOI：10.1248/bpb1978.9.747
出版社：The Pharmaceutical Society of Japan
摘要：The intestinal absorption of tetramethylammonium (TMA) and its derivatives from rat jejunum has been investigated with an in situ loop method and an in vitro everted sac method. At a low concentration, TMA was absorbed rapidly from the in situ intestinal lumen without being metabolized in the tissue and the rate of absorption was dependent upon the concentration used. The profile of TMA absorption included two processes, i.e. saturable and non-saturable. The absorption of TMA was inhibited competitively by analogs that have a Ntrimethyl group in their structure. Among them, choline showed the strongest inhibition to TMA absorption. The inhibitory potency of these analogs was related to their chemical structure. Although TMA was not transported into the intracellular fluid of the everted intestine against a concentration gradient, the tissue accumulation of TMA was inhibited by 2, 4-dinitrophenol (2, 4-DNP), a metabolic inhibitor, and was highly dependent upon the incubation temperature. These findings demonstrate that TMA is absorbed through the rat small intestine by a carrier mediated transport system. An apparent K_t of 0.73 mM and a maximum V of 11.5 nmol/g tissue wet wt/min were determined by an in situ loop method. It was also suggested that the endogenous quaternary ammonium compound, choline, might be absorbed by the same carrier system.
关键词：tetramethyl ammonium