Effect of essential amino acids on absorption of phenylalanine by rat intestine

Résumé L'effet d'un mélange des acidés aminés essentiels sur l'absorption de phénylalanine par l'intestin de rat a été étudié. On a trouvé que le mélange, s'il est en contact direct avec l'intestin, peut augmenter l'absorption de phénylalanine. Ces résultats sont interprétés et plusieurs hypothèses sont émises pour expliquer ce phénomène.     

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).     

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.     

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.     

The influence of diuretics on the absorption of salts,glucose, and water from the isolated small intestine of the rat

Zusammenfassung (1) Unter dem Einfluss von Mersalyl (5×10^–4 m) und Hydrochlorothiazid (2×10^–3 m) nimmt die Cl-Konzentration in der resorbierten Flüssigkeit ab, während die Na-Konzentration gleich bleibt und die Glucose-Konzentration ansteigt. Gleichzeitig kommt es zu einer osmotisch äquivalenten Einschränkung der Wasserresorption.(2) Die prozentuale Hemmung der Wasserresorption durch Mersalyl nimmt zu bei höherer Cl^–-Konzentration in der angebotenen Flüssigkeit und hängt zwischen pH 6,5 und 7,4 nicht von der H⁺-Konzentration ab.(3) Die Wirkung von Mersalyl lässt sich mit Cystein aufheben und ist auchin vivo an der abgebundenen Darmschlinge nachweisbar.(4) Der Glucosetransport und die Calciumresorption werden durch Mersalylkonzentrationen, die die Wasser-und Natriumresorption um 30% hemmen, nicht beeinträchtigt. Der Durchtritt von Calcium durch die Darmwand ist auf das 1,5fache erhöht, es häuft sich dabei in der resorbierten Flüssigkeit an.(5)p-Chloromercuribenzoat hemmt in Konzentrationen, die die Natrium- und Wasserresorption um 40% vermindern, den Glucosetransport ebenfalls um 40%. Im Unterschied zu Mersalyl setzt es die Cl^–-Konzentration der resorbierten Flüssigkeit nicht herab.

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A preliminary report was presented at the 25th Meeting of the German Pharmacological Society in September 1959, Basel.     

The role of parathyroid hormone and calcitonin in magnesium absorption in the rat small intestine

Summary We studied duodenal and ileal magnesium (Mg) absorption in intact, parathyroidectomized (PTX), thyroid-(TX) and thyroparathyroidectomized (TPTX) rats with iodine hormones replaced, and, additionally, in PTX rats receiving bovine parathyroid hormone 1–34 and 1,25-dihydroxyvitamin D₃, respectively. Ma absorption was reduced after PTX and TPTX in the duodenum, but not in the ileum, whereas TX had no influence on duodenal or ileal Mg absorption. Both bovine parathyroid hormone 1–34 and 1,25-dihydroxyvitamin D₃ increased Mg absorption in the duodenum and the ileum in PTX rats.Acknowledgments. We are grateful to B. Schreiber, K. Schwille and I. Goldberg for technical and secretarial help. Supported by Deutsche Forschungsgemeinschaft (Schw 210/3). Reprint requests to P.O.S., University Hospital, Maximiliansplatz, D-8520 Erlangen.     

Effect of alcohol ingestion on the epithelial cell population in rat small intestine

Summary Chronic administration of alcohol to well-nourished rats led to striking changes in the small intestinal cell population. The present experiments corroborate the view that alcohol is directly toxic to the small intestine.The authors wish to thank Mr.P. R. Gaspar for the technical assistance.     

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.     

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.     

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.     

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.