Glucose excretion

Pharmacokinetics Fructose Fructose is slowly absorbed from the Gl tract. Metabolized in liver by phosphorylation and partly converted to liver glycogen and glucose. Excreted in urine. Dextrose Dextrose is rapidly absorbed from Gl tract. Distributed and stored throughout tissues. Metabolized in liver to carbon dioxide and water. 

Glucose The small amount of glucose excreted normally by the kidneys generally produces a result considered negative to trace. 

Clinical inosituria was first observed in 1858, shortly after myo-inositol had been discovered.107 It is a usual concomitant of diabetes mellitus and an extended debate has been waged as to whether inosituria is associated with the glucosuria (D-glucose excretion), characteristic of this disease or with the polyuria (excessive urine volume). The debate was apparently resolved in favor of the former hypothesis by the results of careful studies by Daughaday and coworkers.108 These workers found that, in both humans and rats, the reabsorption of myo-inositol in the kidney is inhibited by high loads of D-glucose. 

As shown in Fig. 2, the control rats exhibited glucosuria 1 to 3 months after the 90% pancreatectomy. However, in rats receiving 0.5 g kg nicotinamide or 0.05 g kg" 3-aminobenzamide daily, the urinary glucose excretion level decreased markedly. Plasma glucose levels, before and after an intravenous glucose load, in the rats receiving the poly(ADP-ribose) synthetase inhibitors were also significantly decreased in... 

Fig. 2. Urinary glucose excretion in partially depancreatized rats with or without poly(ADP-ribose) synthetase inhibitor injection. 1, 2, and 3 months after the 90% pancreatectomy, the urine of each rat was collected for 24 h. Urinary glucose levels were measured by the glucose oxidase method. O Control rats nicotinamide-injected rats 3-aminobenzamide-injected rats. Statistical significance of differences between rats treated with and without poly(ADP-ribose) synthetase inhibitors was analyzed using Student s t test. Each point is the mean for five different rats vertical bars show SD when larger than the symbol indicating the mean value., and = p<0.10, p<0.05, and p<0.025 vs control rats. The time after the partial pancreatectomy is shown on the abscissa...

The renal glucose loss in phlorizin diabetic rats was more than 1 g per 24 hours (Figure 11). Therefore, in excess of 2 g of protein had to be metabolized to glucose. If expressed as body weight, the glucose excretion amounted to 3-5 g per kg per day, and the nitrogen loss to 2-3 g per kg body weight per day. 

Figure 11. Sugar excretion following intravenous infusions of various carbohydrates (D = 5.6 g per day) and phlorizin (D = 0.01 g per day) in rats. Hatched bars = glucose excretion, open bars = fructose or polyol excretion.

Evidence for the pathway of the catabolism of valine has also been sought from the nature of the distribution pattern of the label in glucose (of hver glycogen) or glucose excreted in the urine by phlorizin-ized rats. 

In clinical medicine, the tests most often used to detect abnormalities of carbohydrate metabolism are determination of glucose excretion in the urine and estimation of the glucose concentration in the blood during fasting and after administration of a large dose of glucose (glucose tolerance... 

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