The use of sacs of everted small intestine for the study of the transference of substances from the mucosal to the serosal surface

Wilson, Tony; Wiseman, G.

doi:10.1113/jphysiol.1954.sp005036

Cited by 1,142 publications

(338 citation statements)

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“…Everted sacs were prepared using the method of Wilson and Wiseman (1954). The rat was killed with anaesthetic ether.…”

Section: Tissue Levels Of Deoxycholatementioning

confidence: 99%

Inhibition of Intestinal Uptake of Amino Acids by Unconjugated Bile Salt

Burke¹,

Gracey²,

Thomas³

et al. 1976

Aust J Exp Biol Med

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Summary. The uneonjugatcd bile salt, sodium deoxycholate, at a concpntration of 0-5 ni\f was shown to inhibit the intc-stinal nptake of the amino ai-id-s L-glycinp, L-Ieucine. L-proliiie, L-lysine ami L-tyrosine in rats in vitro. This effect was acutely revprsibte except for the basic aniinn acid L-Iysim* and is therefore not .simply due to tissne daniaK:*. These results, and the recent finding that sodium deoxj'cholate inhibits intestinal absorption of amino acids in vivo. sugKPst that impaired intestinal aniino acid transport muy contribute to hypoproteiiiaeniia in patients with bacterial ovprjirowth in thf upper snuill intestine in whom tlroxytholatc is present in the smati intestinal Imiicn in excessive conceiitration.s.INTRODUCTION.

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“…Everted sacs were prepared using the method of Wilson and Wiseman (1954). The rat was killed with anaesthetic ether.…”

Section: Tissue Levels Of Deoxycholatementioning

confidence: 99%

Inhibition of Intestinal Uptake of Amino Acids by Unconjugated Bile Salt

Burke¹,

Gracey²,

Thomas³

et al. 1976

Aust J Exp Biol Med

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“…Preparation of Everted Xacs Everted sacs were prepared by a modification of the procedure described by Wilson and Wiseman [24]. Male albino random-bred Sabra rats (150-200 g) starved overnight were used.…”

Section: Purification Of Li'olatesmentioning

confidence: 99%

Uptake and Reduction of Radioactive Folate by Everted Sacs of Rat Small Intestine

Selhub¹,

Brin²,

Grossowicz³

1973

European Journal of Biochemistry

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Uptake of pteroylglutamic acid ([2-14C]PteGlu) by everted sacs of rat small intestine was studied. Under conditions of zero initial concentration gradient, a net transport of PteGlu from the mucosal to the serosal side was found a t initial concentrations not exceeding 7 pM.Using a simplified chromatographic procedure for estimation of reduced folates it was found that part of the transported PteGlu was converted to reduced forms, tentatively identified as tetrahydropteroylglutamic acid (H,PteGlu) and its methyl and formyl derivatives. PteGlu was reduced throughout the small intestine. The reduction was time and concentration dependent with an apparent K , of 1.55 pM.Low concentrations of methotrexate (23 nM) inhibited the reduction of PteGlu but did not affect its transport; a t a much higher concentration (3 pM) methotrexate decreased the accumulation of folates in the tissue without significantly affecting the vitamin concentration in the serosal solution.Although folates are readily absorbed from the intestine, the mechanism of absorption of this vitamin has been a subject of conflicting reports. Some workers have described transport against a concentration gradient and/or saturable process both but the findings were not confirmed [16].The present study deals with the uptake, reduction and methylation of labelled PteGlu by everted sacs of rat intestine and dicsusses briefly the mechanism of the uptake. MATERIALS AND METHODS Chemicals Radiochemical Centre (Amersham, Bucks). ~-[6-3H]-Formyl-H,PteGlu was a generous gift of Dr E. J.Pastore (Tufts University, School of Medicine, Boston, Massachusetts). Unlabelled PteGlu was obtained from the Nutritional Biochemical Corp. (Cleveland, Ohio). Folate solutions were purified on small DEAE-cellulose-Celite columns or by paper chromatography (see below) ; they were stored a t -70 "C. Methotrexate was a product of Lederle Laboratories (Pearl River, K.Y.).The microbiological determination of folates was carried out with Lactobacillus casei (ATCC 7469) and Pediococcus cerevisiae (ATCC 8081) using the BBI, medium (Baltimore Biological Laboratories, Cockeysville, Maryland).Radioactive folates were also determined with the Packard TriCarb scintillation spectrometer model 3310. Samples (0.05 to 0.25 ml) were added to I0 ml scintillation fluid of the following composition : 120 g naphthalene; 7 g 2,5-diphenyloxazole; 50 mg 1,4-bis-2-(5-phenyloxazolyl)benzene in 1 1 dioxane. Purification of li'olatesSmall quantities (up to 10 pg) of various folates were purified by chromatography on small DEAEcellulose-Celite columns immediately prior to use. The column, which consisted of 0.1 g DEAE-cellulose (Sigma Chemical Co., St. Louis, Missouri; 0.88 mequiv./g) and 0.12 g Celite 545 (Johns Man-

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“…The method provides valuable information about the drug absorption mechanisms as well as the effects of substances increasing or decreasing intestinal absorption [19,20]. It has been suggested that drug transporter molecules are distributed unevenly throughout the small intestine, and the absorption of some drugs has been reported to be higher in the distal parts of the intestine (the ileum and jejunum) compared to the proximal intestinal segments [5,6,21].…”

Section: Discussionmentioning

confidence: 99%