In vitro studies on bilirubin transport by the small intestine of the rat

Resumen Se estudió el transporte de bilirrubina no conjugada en asas intestinales aisladas y perfundidas de rata. Los resultados indican un pasaje bidireccional con la probable participación de un mecanismo de difusión simple.

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This work was supported by grants from the Consejo Nacional de Investigaciones Científicas y Técnicas, República Argentina, National Institutes of Health, Bethesda (Md., USA) and Ministerio de Salud Publica y Bienestar Social de la Provincia de Santa Fé (Republica Argentina).     

In vitro esterification of plant sterols by the esterifying enzyme of the small intestine of rat

The in vitro esterification of plant sterols, beta-sitosterol, campesterol and stigmasterol, by the esterifying enzyme of the small intestine of rat was studied in the presence of saturated and unsaturated fatty acids. Campesterol esterification was highest, followed by sitosterol and stigmasterol irrespective of the type of fatty acid. Both campesterol and sitosterol esterification was greater with unsaturated fatty acids than with saturated fatty acids.     

In vitro esterification of plant sterols by the esterifying enzyme of the small intestine of rat

Summary The in vitro esterification of plant sterols,-sitosterol, campesterol and stigmasterol, by the esterifying enzyme of the small intestine of rat was studied in the presence of saturated and unsaturated fatty acids. Campesterol esterification was highest, followed by sitosterol and stigmasterol irrespective of the type of fatty acid. Both campesterol and sitosterol esterification was greater with unsaturated fatty acids than with saturated fatty acids.Acknowledgments. Financed by the Emery Goff Research Award from the American Heart Association, Louisiana, Inc. and the USPHS research grant HL-08974 from the National Institutes of Health, Bethesda, Md.     

Effect of diethylstilbestrol on glucose absorption by rat small intestine in vitro

Resumen El dietilestilbestrol inhibe la absorción activa de glucosa en el intestino de rata in vitro, aunque no impide la entrada del azucar en las células de la mucosa. La difusión pasiva de arabinosa y xilosa es facilitada por la droga.     

Influence of the transport of amino acids on glucose and sodium transport across the small intestine of the albino rat incubatedin vitro

Riassunto Proseguendo precedenti ricerche si mette in evidenza che esiste una correlazione anche tra trasporto di sodio e trasporto di vari amino acidi attraverso l'intestino tenue isolato di ratto albino. Se ne deduce che presumibilmente ogni sostanza capace di essere trasportata attivamente stimola il trasporto di sodio e che quest'ultima funzione diventa solo un indice dell'attività totale di trasporto dell'epitelio intestinale.

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This work has been supported by a research grant of the Consiglio Nazionale delle Ricerche, Roma.     

Galactose and leucine transport in the developing rat small intestine

Summary Jejunal transport of galactose and leucine was studied in 9-45-day-old rats by means of the everted sac technique. Maximum transport was observed in 9-10-day-old rats, but then decreased until the 22nd day, and remained unchanged from then on. There were no remarkable differences in the pattern of galactose and leucine transport over this period.     

Thiamine transport by human intestine in vitro

Summary Surgical specimens of human gastrointestinal mucosa and muscle were incubated in vitro with thiaminethiazole-2-¹⁴C. Labelled thiamine uptake was uphill in mucosal tissues and downhill in muscle. Small intestinal mucosa accumulated labelled thiamine in a phosphorylated form, while gastric and colonic mucosa, as well as muscular layers of all gastrointestinal segments studied, did not.This work was supported in part by a grant from the Italian Research Council, Rome, Italy.     

Transport of thiamine by the small intestine in vitro

Riassunto È stato studiato il trasporto in vitro della tiamina con la tecnica dei sacchetti intestinali rovesciati di ratto. Usando una concentrazione di tiamina molto bassa (0.21 µM/l) si dimostra il passaggio della vitamina contro gradiente di concentrazione. L'impiego di inibitori metabolici e di analoghi strutturali della tiamina conferma l'esistenza di un trasporto attivo. In particolare l'inibizione del trasporto da parte della sola piritiamina, noto inibitore della tiaminochinasi intestinale, suggerisce la possibilità che alla base del meccanismo di trasporto della tiamina vi sia la sua fosforilazione.     

Effect of dinitrophenol on the pattern of methionine transport along the small intestine of the rat

Zusammenfassung Der Transport desL-Methionins durch die Rattendarmwand wurde in vitro untersucht. Die Transportgeschwindigkeit im Verlaufe von 1 h ist am höchsten im unteren Jejunum und im oberen Ileum (Abschnitte 4, 5 und 6). DNP-verursachte Hemmung ist in diesen Darmabschnitten am stärksten, was das Verschwinden des Maximums bewirkt.     

Epithelial cell swelling during incubation of rat small intestine in vitro

Résumé L'augmentation du fluide du tissu de l'intestin grèle incubé in vitro s'accompagne d'un accroissement du volume des cellules épithéliales.     

Calcium dependence of protein transport by the small intestine of the new-born pig

Resumen El transporte de albumina en el intestino delgado del cerdo esta asociado con un aumento en el transporte de fluido. Ambos transportes son inhibidos por altas concentraciones de calcio. Ausencia de calcio tambien inhibe el transporte de albumina. Condiciones optimas en el transporte de albumina y fluido se obtienen usando Cl₂Ca4 mM en el medio. Se deducen analogias al comparar estos resultados con resultados similares en ameba, obtenidos de la literatura.     

Amino acid transport by small and large intestine of newborn pig

Summary Unidirectional fluxes of different amino acids have been determined across newborn pig small intestine and colon. The systems responsible for amino acid transport are present in the same proportion in both tissues. Colonic transport of amino acids appears to represent a transient overspill function of the small intestine.     

Evaluation of O2 availability during glucose transport in everted sacs of rat small intestine

Riassunto Misurando il consumo di O₂ in funzione della pO₂ nel mezzo di incubazione è stato dimostrato che i sacchetti di intestino tenue rovesciato di ratto si trovano in condizione di parziale anaerobiosi nel corso dell'incubazione in liquido fisiologico contenente glucoso. Ciò viene posto in relazione con la notevole produzione di acido lattico da parte dell'intestino isolato mantenuto in tali condizioni.     

Thiamine diphosphatase in rat small intestine

Summary TDPase is located mostly in the proximal portion of the small intestine and its activity, like that of ALPase, decreased markedly in thiamine deficiency. The decreased enzyme activities were restored after thiamine or vitamin D₃. Kinetic and other studies of the purified enzyme indicated the identity of the two enzymes.Acknowledgment. We thank Miss.T. Yagura and Miss.H. Kuroda for technical assistance.     

Synapses in the rat stomach and small intestine

Riassunto Nel plesso mienterico dello stomaco e dell'intestino tenue di ratto si osservano tipiche giunzioni sinaptiche sia axo-somatiche sia axo-dendritiche. Il numero di contatti sinaptici per unità di superficie di sezione o per cellula nervosa è piÚ di sei volte maggiore nello stomaco che nell'intestino tenue.