load. Further noted were reductions in increases in both plasma glucose and insulin levels following a sucrose (1.5g/kg body weight) plus PF-C (0.6g/k

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めぐのぜんじゅう
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1 The Effects of Indigestible Dextrin on Sugar Tolerance: I. Studies on Digestion-Absorption and Sugar Tolerance Shigeru WAKABAYASHI1)2) It is widely acknowledged that high viscosity water-soluble dietary fibers such as pectin and guar gum affect a lowering of blood glucose levels and a reducing of insulin secretion following a sugar load. However, as dietary fibers vary in origin and in chemical properties, their physiological functions differ as well. In this study the effects of Indigestible Dextrin (PF-C), a low viscosity, water-soluble dietary fiber obtained through acid and heat-treatment of potato starch, on various aspects of sugar tolerance were examined. First, the influence of PF-C on sucrose hydrolysis was examined in rat intestinal mucosa cell homogenate confirming that PF-C did not inhibit sucrase activity. Then, in order to investigate the influence of PF-C on sugar digestion-absorption, an experiment was performed by using the everted intestinal sac of the rat in vitro. PF-C did not have an effect on glucose-transport of hydrolyzed-glucose into the serosal medium, whereas PF-C did inhibit the transport from sucrose, with no change in the hydrolysis of sucrose.recently, Crane et al. reported that there is a specific route for hydrolyzed glucose from sucrose in glucose-absorption on the enteric surface (disaccharidase related transport system). The possibility exists that PF-C specifically affects this pathway. Further, total glucagon released into the serosal medium stimulated by both glucose and sucrose were reduced by PF-C. On the basis of these results, an oral sugar tolerance test was conducted in both rats and healthy human subjects. In male Sprague-Dawley rats (8 weeks old, g) concurrent administration of PF-C (0.6g/kg body weight) reduced an increase in plasma insulin levels with no change in glucose levels following a glucose (1.5g/kg body weight)

2 load. Further noted were reductions in increases in both plasma glucose and insulin levels following a sucrose (1.5g/kg body weight) plus PF-C (0.6g/kg body weight) load to that of the sucrose (1.5g/kg body weight) single load. These findings reflect the above mentioned in vitro results. Moreover, in healthy male subjects the increase in both plasma insulin and glucagon-like immunoreactivity (Gut GLI) levels following a Trelan-G75 load were significantly reduced by concurrent administration of PF-C. From these observations it would appear that the effectiveness of reducing insulin secretion by PF-C results due to the decrease in sugar absorption by inhibiting the disaccharidase - related transport system. As glucagon-like peptide 1 (GLP-1), [an incretin in the enteroinsular axis] secreted with Gut GLI from intestinal L cells, is known to enhance insulin secretion following a sugar load, the resulting effectiveness by PF-C to reduce insulin secretion is thought to be attributed to the action on this enteroinsular mechanism. axis Key words: Indigestible dextrin, Dietary fiber, Everted intestinal sac, Sugar tolerance, Enteroglucagon

4 Table 1 Effect of various dietary fibers on sucrase activity.

5 Fig. 1 Time-course of glucose transport by rat intestinal everted sac. Everted sac was incubated with glucose solution supplemented with or without indigestible dextrin (PF-C). Left panel shows the changes in glucose concentrations in the mucosal medium. Center and right show the changes in glucose concentrations and total glucagon release into the serosal medium, respectively. Values (Mean } SEM) not sharing a common superscript on the same time are significantly different from each other (p<0.05). [ œ150mg/dl glucose; n=6, 150mg/dl glucose + 60mg/dl PF-C; n=6, 150mg/dl glucose mg/dl phloridzin; n=6, 150mg/dl glucose + 60mg/dl PF-C 43.6mg/dl phloridzin; n=6, 60mg/dl PF-C ; n= 6, 43. 6mg/dl phloridzin; n=3]

6 Fig. 2 Time-course of sucrose transport by rat intestinal everted sac. Everted sac was incubated with sucrose solution supplemented with or without indigestible dextrin (PF-C). Upper two panels show the changes in sucrose and glucose concentrations in the mucosal medium, respectively. Lower left panel shows the changes in glucose concentrations in the serosal medium. Right shows total glucagon release into the serosal medium. Values (Mean } SEM) not sharing a common superscript on the same time are significantly different from each other (p<0.05). [ œ300mg/dl sucrose; n=14, 300mg/dl sucrose + 60mg/dl PF-C; n=13, 300mg/dl sucrose mg/dl phloridzin; n=6, 300mg/dl sucrose + 60mg/dl PF-C mg/dl phloridzin ; n=6]

7 Fig. 3 Changes in plasma glucose and insulin levels after the administration of glucose (upper panels), sucrose (lower panels), and with indigestible dextrin (PF-C) in rats. Each point (Mean } SEM) not sharing a common superscript on the same time are significantly different from each other (p<0.05). [Upper panels: œglucose 1.5g/kg body weight; n=6, glucose 1.5g + PF-C 0.6g/kg body weight; n=6, glucose 1.5g + pectin 50mg/kg body weight; n=6, -- --PF-C 0.6g/kg body weight; n=4, Lower panels : œsucrose 1.5g/kg body weight; n=18, sucrose 1.5g + PF-C 0.6g/kg body weight; n=18]

8 Fig. 4 Changes in glucose (upper panel: \ \), insulin (upper panel:---), Gut GLI (glucagon-like immunoreactivity; lower panel: \ \), and GI (glucagon immunoreactivity; lower panel:---) levels after the administration of Trelan-G75 alone ( œ), and with indigestible dextrin (PF-C: ) in five male healthy subjects. Each point is the Mean } SEM. The statistical comparisons were made between groups (*: p<0.05 **: p<0.01).

11 1) Jenkins, D.J.A., Leeds, A.R., Wolever, T.M.S., Goff, D.V., Alberti, K.G.M.M., Gassull, M.A. and Hockaday, T. D. R.: Unabsorbable carbohydrates and diabetes; decrease post-prandial hyperglycaemia. Lancet, 1976; 2 : ) Jenkins, D.J.A., Wolever, T.M.S., Nineham, R., Taylor, R., Metz, G.L., Bacon, S. and Hokaday, T.D.R.: Guar crispbread in the diabetic diet. Br. Med. J., 1978; 2: ) Jenkins, D.J.A., Wolever, T.M.S., Jenkins, A. and Taylor, H.: Dietary fibre, carbohydrate metabolism and diabetes. Molec. Aspects Med., 1987; 9 : ) Jenkins, D.J.A., Wolever, T.M.S., Leeds, A.R., Gassull, M.A., Dilawari, J.B., Goff, D.V., Metz, G.L. and Alberti, K.G.M.M.: Dietary fibres, fibre analogue and glucose tolerance: importance of viscosity. Br. Med. J., 1978; 1: ) Miranda, P.M. and Horwitz, D.L.: High fiber diets in the treatment of diabetes

12 mellitus. Ann. Int. Med., 1978; 88: ) Morgan, L.M., Goulder, T.J., Tsiolakis, D., Marks, V. and Alberti, K.G.M.M.: The effect of unabsorbable carbohydrate on gut hormones. Diabetologia, 1979; 17: ) Dahlqvist, A.: Assay of intestinal disaccharidases. Anal. Biochem., 1968; 22: ) Lowry, O.H., Rosebrough, N.J., Farr, A.L. and Randall, R.J.: Protein measurement with the folin phenol reagent. J. Lab. Chem., 1951; 193: ) Ramaswamy, K., Malathi, P., Caspary, W.F. and Crane, R.K. : Studies on the transport of glucose from disaccharides by hamster small intestine in vitro. I. Evidence for a disaccharidase-relatedtransport system. Biochem. Biophys. Acta., 1973; 307: ) Ramaswamy, K., Malathi, P., Caspary, W.F. and Crane, R.K. : Studies on the transport of glucose from disaccharides by hamster small intestine in vitro. II. Characteristics of the disaccharidase-related transport system. Biochim. Biophys. Acta., 1974; 345: ) Ramaswamy, K., Malathi, P. and Crane, R.K.: Demonstration of hydrolase-related glucose transport in brush border membrane vesicles prepared from guinea pig small intestine. Biochem. Biophys. Res. Commun., 1976; 68: ) Alvarado, F. and Crane, R.K.: Phloridzin as a competitive inhibitor of the active transport of sugars by hamster small intestine, in vitro. Biochim. Biophys. Acta., 1962; 56: ) Barry, R.J.C., Dikstein, S., Matthews, J., Smyth, D.H. and Wright, E.M.:

13 23) Creutzfeldt, W., Ebert, R., Nauck, M. and Stockman, F.: Disturbance of the enteroinsular axis. Scad. J. Gastroenterol., 1983; 18 (suppl. 83): ) Shima, K., Sawaki, N., Morishita, S., Tarui, S. and Nishikawa, M.: Effect of phenformin on the response of plasma intestinal glucagon-like immunoreactivity (GLI) to oral glucose in gastrectomized subjects. Proc. Soc. Exp. Biol. Med., 1975; 150:

STUDIES ON THE RELATION BETWEEN LATE DUMPING SYNDROME AND GLUCAGON RESPONCES TO GLUCOSE Taisuke MATSUI The First Department of Surgery, Nara Medical U

STUDIES ON THE RELATION BETWEEN LATE DUMPING SYNDROME AND GLUCAGON RESPONCES TO GLUCOSE Taisuke MATSUI The First Department of Surgery, Nara Medical University, Kashihara (Director: Prof. H. Nakano) This