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Background: Establishing animal models with metabolic disorders similar to human metabolic syndrome (MS) is important. In terms of eliciting a full array of MS, we have previously shown that Wistar rats are more responsive to sucrose water drinking than are C57BL/6J mice. This study was aimed at investigating the underlying molecular mechanism of sucrose water-induced MS in Wistar rats., Methods: Male Wistar rats were divided into 2 groups (n = 8 for each group) which were given plain water (C group) or 30% sucrose water (SW group) to drink ad libitum. After 20 weeks, the transcriptional levels and protein translocation of hepatic sterol regulatory element-binding protein-1c (SREBP-1c) and carbohydrate response element-binding protein (ChREBP) as well as the protein levels of protein tyrosine phosphatase-1B (PTP-1B) in insulin-responsive tissues (liver, muscle, and adipose tissue) were measured., Results: The sucrose water regimen successfully elicited visceral obesity, hypertriglyceridemia, insulin resistance, and high blood pressure. The upregulation of de novo lipogenesis in the liver of the sucrose water-treated rats was demonstrated by an increased activity of enzymes, mRNA levels of lipogenic proteins, and nuclear levels of SREBP-1c and ChREBP. Moreover, in the sucrose water-treated rats, protein levels of PTP-1B were significantly increased in liver and skeletal muscle but decreased in adipose tissue., Conclusion: The susceptibility of Wistar rats to sucrose water-induced MS is associated with the transactivation of SREBP-1c and ChREBP in the liver, and PTP-1B is involved in the upregulation of de novo lipogenesis in the liver and the pathology of systemic insulin resistance in rats with MS chronically induced by drinking sucrose water., (Copyright © 2010 S. Karger AG, Basel.)

Background/aims: Isomaltulose (alpha-D-glucosylpyranosyl-1,6-D-fructofuranose) is a natural disaccharide used in human nutrition. It is structurally related to sucrose, but more slowly hydrolyzed and absorbed. Because this sugar's metabolic effects are poorly characterized, we compared the effects of chronic ad libitum access to high-isomaltulose and high-sucrose diets on glucose metabolism in rats., Methods: Adult male rats were offered 62% isomaltulose, sucrose or starch diets ad libitum for 26 (trial 1) or 56 (trial 2) days. After 2- to 3-week adaptation, plasma glucose, fructose and insulin were measured after test meals of the adaptation diet., Results: The main finding was that both plasma glucose and plasma insulin concentrations were transiently but markedly increased after sucrose test meals compared to isomaltulose or starch meals. These differences were not associated with consistent differences in food intake, body weight gain or adiposity., Conclusions: Chronic isomaltulose feeding has beneficial effects on postprandial glucose metabolism in comparison to sucrose feeding in rats, although the effects are modest. Further work is warranted to determine whether substitution of isomaltulose for sucrose or other sweet carbohydrates might be therapeutically useful in patients with, or at risk for, insulin resistance or type 2 diabetes mellitus.

Unlabelled: Oral clearance and acid production were observed in 30 volunteers following the ingestion of sharp cheddar cheese (CC) and in 9 volunteers following the ingestion of milk chocolate (MC) and low-fat yogurt, and then when MC was eaten immediately after CC (CC/MC) and when CC was eaten following MC (MC/CC). After each test food or food combination had been ingested the volunteers were monitored at five different tooth sites. At each site, using an absorbent paper point, 4 oral fluid samples were collected at 30 min intervals. The five paper points from each sampling occasion were pooled, extracted with 1 ml of water and analyzed qualitatively and quantitatively for both carbohydrates and organic acids using HPLC. Data obtained for each food was averaged and subjected to statistical evaluation. With the CC, glucose clearance was prolonged, due to intermediate lactose degradation into galactose and glucose. The quantity of lactic acid produced during the four intervals was monitored for each of the test foods and their combinations., Results: CC, MC, CC/MC, MC/CC 30 min after ingestion: 1.64, 3.47, 4.68, 2.97; after 60 min: 1.30, 1.24, 1.28, 1.43; after 90 min: 1.58, 1.02, 0.76, 0.43; after 120 min: 1.27, 0.90, 0.70, 0.42 mmol lactic acid/l oral fluid, respectively. The average total amount of lactic acid obtained during the two hour test period was (highest) CC/MC > MC > CC > MC/CC (lowest). The lowest amount of intra-oral lactic acid was observed (Student's t test, p < 0.05) when cheddar cheese (CC) was eaten immediately after the milk chocolate (MC)., Clinical Significance: Consumption of cheese (cheddar), immediately after a sweet meal, significantly reduces (approx. 30%) the amount of lactic acid produced in the oral cavity, when compared to the amount of acid obtained from the sweet food alone., (Copyright 2001 S. Karger AG, Basel)

Background/aims: In order to determine whether the response to a sucrose-rich diet (SRD) during pregnancy in the rat varies depending on the strain, the responsiveness to a SRD (63 g sucrose/100 g) during pregnancy in Wistar and Sprague-Dawley rats was studied., Methods: One group of rats of each strain was fed the SRD, whereas another group received the same diet except that sucrose was replaced by an equal amount of cornstarch. Half of the rats were mated, and all animals were studied 20 days later., Results: Initial body weight did not differ among groups, but final body weight of pregnant Wistar rats was lower than in Sprague-Dawley, and this difference corresponded to a decrease in fetal body weight in the former. Feeding a SRD did not modify pregnancy outcome in either rat strain. Plasma triglycerides increased with a SRD, although this effect was milder in Wistar pregnant rats than in the other groups. Adipose tissue lipoprotein lipase activity was lower in pregnant than in virgin rats, but no differences were found as result of either diet or rat strain. Liver triglyceride concentration increased in virgin rats fed SRD, the effect being greater in Sprague-Dawley than in Wistar rats., Conclusion: Differences in the response to a SRD in pregnant and virgin rats do not depend on the strain of rats used., (Copyright 2001 S. Karger AG, Basel)

Unlabelled: Oral lactic acid production was studied on 11 healthy dental student volunteers (5 males and 6 females) during clearance of five solutions containing 5, 10, 15, 20 and 30% of sucrose. Oral fluid samples were collected at times zero, immediately before taking the sucrose solutions ('baseline'), and 15 min following intake of the solutions. The samples were analyzed qualitatively and quantitatively for the presence of lactic acid and remaining sugars using high-performance liquid chromatography (HPLC). Results indicate that the amount of lactic acid in oral fluid significantly increased with increasing sucrose concentrations, up to 15% sucrose. With the higher sucrose concentrations (20 and 30%) equivalent or lower amounts of lactic acid were obtained. The threshold level for maximum lactic acid production was found to be between 10 and 15% sucrose. Statistical analysis of the data (Student's t test) indicated a significant difference in lactic acid production between the 5 and 10% sucrose solutions versus the 15, 20 and 30% sucrose solutions tested (p < 0.05)., Clinical Significance: Ingestion of solutions with higher sucrose concentrations (>15%) produced similar amounts or less of lactic acid during oral clearance than solutions containing lower sucrose concentrations (<15%)., (Copyright 2000 S. Karger AG, Basel)

The presence of carbohydrates and organic acids was monitored in the oral cavity over a 3-hour period following the ingestion of six foods containing cooked starch (popcorn, potato chips, corn flakes, bread stick, hard pretzel and wheat cracker) and compared to a food containing sugar (chocolate-covered candy bar). Oral fluid samples were collected at 30-min intervals from five different tooth sites from 7 volunteers using absorbent paper points. Samples were analyzed for carbohydrates and organic acids using high-performance liquid chromatography. Analytical data for each food were pooled and compared to the results of the sugar food. The amount of lactic acid produced 30 min after ingestion was highest with the potato chips and lowest with the corn flakes. Potato starch contributed more readily to oral lactic acid production than wheat or corn starch. A direct linear relationship existed between lactic acid production and the presence of oral glucose produced from starch, which occurred via the metabolites maltotriose and maltose. Oral clearance of foods containing cooked starch proceeded significantly slower than that of the sugar food, thus contributing to a prolonged period of lactic acid production.