RESUMEN
The effect of xylitol and glucose on the rate of gastric emptying and intestinal transit and on motilin, gastric inhibitory polypeptide (GIP), and insulin release were studied in human volunteers. A single oral dose of 200 mL water containing 30 g glucose or 30 g xylitol, mixed with a 99mtechnetium-tin (99mTc-Sn) colloid, was used. Similar dosing without the label was used in motilin, GIP, and insulin studies. Xylitol decreased the rate of gastric emptying but concomitantly accelerated intestinal transit compared with glucose. The half-times for gastric emptying were 77.5 +/- 4.6 and 39.8 +/- 3.4 min after ingestion of xylitol and glucose solutions, respectively. Glucose suppressed motilin and stimulated GIP secretion; xylitol stimulated motilin secretion but had no effect on GIP, which is currently the main candidate for the role of enterogastrone. The accelerated intestinal transit and increase in plasma motilin observed after xylitol ingestion were thought to be causally related to the diarrhea and gastrointestinal discomfort produced by it.
Asunto(s)
Vaciamiento Gástrico/efectos de los fármacos , Polipéptido Inhibidor Gástrico/metabolismo , Glucosa/farmacología , Insulina/metabolismo , Motilina/metabolismo , Compuestos de Tecnecio , Compuestos de Estaño , Xilitol/farmacología , Coloides , Diarrea/inducido químicamente , Femenino , Humanos , Secreción de Insulina , Cinética , Masculino , Tecnecio , Estaño , Xilitol/efectos adversosRESUMEN
A placebo-controlled double-blind cross-over study was carried out to assess the effect of chromium supplementation (200 micrograms trivalent chromium daily for 6 wk) on glucose tolerance, insulin response, long-term diabetic control, and serum lipids in 10 noninsulin-dependent diabetics aged 37 to 68 yr. After chromium supplementation 24-h urinary chromium excretion showed a 9-fold increase indicating a positive chromium balance in the subjects. There was no significant difference between chromium supplementation and placebo periods in glucose tolerance and in fasting or 2-h postglucose serum insulin levels but the 1-h postglucose serum insulin level was slightly lower on chromium supplementation than on the placebo (55 +/- 9.0 versus 64 +/- 11; p less than 0.01, paired t test). Serum total cholesterol and triglycerides and their high-density, low-density, and very low-density lipoprotein subfractions showed no change after chromium supplementation as compared to the placebo period.