Disaccharidase rhythm in rat small intestine; no relationship with mitosis rhythm.

Same circadian difference in the specific activities of sucrase and maltase was observed in the purified brush border fraction as in the crude homogenate of the mucosa of rat small intestine, suggesting that the disaccharidase rhythm is not due to the mitosis rhythm of epithelial cells.     

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.     

Diurnal rhythm of active calcium transport in rat intestine

Summary The active calcium transport along the small intestine of adult rat was shown to exhibit daily rhythmic variations of considerable amplitude. Both the light-dark cycle and the time of food presentation acted as synchronizers of the rhythm observed.This work has been supported by Polish Academy of Sciences within the project MR II.1.1.6.     

Diurnal rhythm of active calcium transport in rat intestine

The active calcium transport along the small intestine of adult rat was shown to exhibit daily rhythmic variations of considerable amplitude. Both the light-dark cycle and the time of food presentation acted as synchronizers of the rhythm observed.     

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.     

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.     

Oxygen consumption of the rat small intestine during infection with nematospiroides dubius

Summary Qo₂ of jejunal rings did not differ significantly between uninfected rats and rats infected for 7 days withNematospiroides dubius. Qo₂ of isolated jejunal mucosal epithelial cells was significantly greater 7 days after infection than in uninfected controls or at 29–36 days after infection.     

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.     

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.     

Effects of plant sterols on cholesterol concentration in the rat small intestine

Summary The effects of feeding single doses of -sitosterol, campesterol and stigmasterol on cholesterol concentration in the rat small intestine was studied to clarify their roles in cholesterol absorption. The different plant sterols affected free and ester cholesterol concentrations differently in the different intestinal segments suggesting that they have different effects on such intestinal processes as uptake, esterification and possibly synthesis of cholesterol and transport of cholesterol esters out of the mucosal cells into the lymphatics.Acknowledgments. Financed by the Emergy Goff Research Award from the American Heart Association-Louisiana, Inc. and the NHLBI research grant HL-08974 from the National Institutes of Health, Bethesda, Maryland.     

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.     

Starvation-induced changes in the autoradiographic localisation of valine uptake by rat small intestine

We report here the effects of a 72-h fast on the localisation of Na-dependent [3H]-valine uptake by rat small intestine. Starvation results in the earlier appearance of valine transport during cell migration and an enhanced accumulation of the amino acid at the villus tip.     

Starvation-induced changes in the autoradiographic localisation of valine uptake by rat small intestine

Summary We report here the effects of a 72-h fast on the localisation of Na-dependent [³H]-valine uptake by rat small intestine. Starvation results in the earlier appearance of valine transport during cell migration and an enhanced accumulation of the amino acid at the villus tip.Acknowledgments. We wish to thank MW Smith, PS James and IS King (AFRC Institute of Animal Physiology, Babraham, Cambridge) for facilities and advice regarding autoradiography. Financial support from the British Digestive Foundation and Eli Lilly and Company is appreciated.     

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.     

Evidence for no relationship of the pineal activity with the neonatal shrinkage of Leydig cells in the rat

Summary The collective volume of Leydig cells in prenatally pinealectomized newborn rats declined as sharply as in intact newborn rats. Also, the collective volume in pups born in the dark declined in a fashion similar to that in pups born in the light. The results indicate that neither the pineal gland nor the light is responsible for the neonatal shrinkage of Leydig cells.This study was supported in part by a Grant-in Aid for Scientific Research (No. 548067) from the Ministry of Education, Science and Culture of Japan.     

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).