Effect of peroral xylitol on the concentration levels of lipids and electrolytes in rat tissues

The effect of glucose (G) and xylitol (X) feeding on the fat and electrolyte metabolism was studied with 24 adult male rats divided into three groups of 8 for a 30-day experiment. One group was fed the stock diet supplemented with X (3000 mg/kg body wt./day); the second group the same diet supplemented with G (3000 mg/kg body wt./day), and the third the stock diet without added carbohydrates. During the last 24-hr period of the feeding schedule the animals were given ¹⁴C(U)-labeled G or X. Samples of serum, liver, kidneys, pancreas, spleen, duodenum wall, parotid glands, and the entire submandibular and lacrimal glands were analyzed for neutral lipids, phospholipids, Na, K, Mg, Ca, Fe, Cl^? and inorganic phosphorus. The X-fed animals showed smaller weight gains and their lacrimal and submandibular glands were significantly smaller than in other feeding groups. The weights of kidneys, however, did not differ significantly. At least in the case of submandibular glands, the reduced gland weights were associated with decreased levels of tissue K, Ca, Mg, inorganic phosphorus and Cl^?. Several organs of the G-fed animals displayed reduced Na contents. X-fed rats showed elevated concentrations of Fe in livers, kidneys and spleen, increased labeling of serum neutral lipids, and increased concentrations of triglycerides (TG) and free fatty acids (FFA) in lacrimal and submandibular glands. The G-fed animals showed decreased concentrations of serum lysolecithin, but elevated levels of TG in serum and the lacrimal and submandibular glands. X feeding increased serum lysolecithin compared to G feeding. These results suggest that physiological, peroral X administration increases the rate of lipolysis, facilitates the absorption of iron and exerts specific effects on exocrine gland function in rats. Most findings in the X group were significant only when compared to the G group. Minor differences existed when X-fed rats were compared to control rats. Since high carbohydrate diets usually result in reduced plasma FFA and increased plasma TG, the higher FFA and lower TG in the X-fed rats compared to the G-fed group, therefore, represented a lack of high G effects.     

Alterations in electrolyte and iron metabolism in the rat in relation to peroral administration of galactitol, mannitol and xylitol

Groups of 12 Long-Evans male rats were exposed to diets containing 20% galactitol (G), mannitol (M) or xylitol (X) for 5 wk. Serum electrolyte concentrations were within normal ranges for rats in all groups compared to control rats. All polyol-fed animals exhibited diuresis and a lower urinary pH (6.2-5.3) with a concomitant lower excretion of Na+, Cl- and protein (40% of controls). The excretion of K+ was lower in the X-fed rats than in any other group. Urinary Ca2+ excretion was sixfold higher and Mg2+ excretion, twofold higher in all polyol-fed rats than in controls. PO4 and NH4+ excretions were higher than controls in G- and M-fed animals only. Serum aldosterone concentrations in all polyol rats were 60% of those in controls. The serum corticosterone and parathyroid hormone levels were normal. Urinary citric acid was significantly higher in rats fed polyols but oxalic acid excretion was either normal (X) or lower (G,M) than in controls. Concentrations of serum and liver iron were higher in polyol-fed rats than in controls. Nevertheless, the normal serum creatinine and electrolyte concentrations and normal urinary creatinine levels established healthy kidney function. The diuretic effect of the polyols was considered responsible for the changes in the monovalent ion metabolism. The alterations in the excretion of multivalent cations most likely resulted from their increased intestinal absorption facilitated by the general chelating action of these polyols.     

Effect of peroral administration of xylitol on exocrine secretions of monkeys.

The effects of the administration of xylitol on the biochemical properties of monkey parotid and submandibular saliva and lacrimal fluid were investigated. Monkeys (Macaca mulatta) were fed either a sucrose or xylitol diet for 3 days. Ingestion of xylitol was associated with a significant increase of the activity of the salivary lactoperoxidase. The concentration of protein was also increased. Higher lactoperoxidase activity was found in parotid than in submandibular saliva. The concentrations of inorganic phosphate, calcium and SCN ions were practically unaffected. The concentration of SCN ions in pilocarpine stimulated monkey saliva was low (less than 5.5 mg/liter). Peroral administration of 2.5 g of xylitol or sorbitol per day to M. fascicularis resulted in almost similar levels of salivary lactoperoxidase activity. The administration of xylitol orally or by gastric intubation was not found to affect the concentration of lactoperoxidase, protein, phosphate, and SCN and iodine ions in lacrimal fluid. The results suggest that specific dietary sugars have a selective effect on the biochemical properties of saliva.     

Experimental study of the embryotropic effects of various calcium compounds after peroral administration

The ion form as calcium bicarbonate appeared to be most favourable for the correction of mineral distillate content with various calcium compounds. An organocomplex compound--calcium lactate can not be considered as an adequate model for the scientific substantiation of hygienic standards for calcium content in drinking water. Completely demineralized water consumed perorally gives a negative embryotropic effect.     

The comparative oxidation of glucose, fructose, sorbitol and xylitol in normal man

The aim of the study was to compare the effects of fructose, sorbitol and xylitol with those of glucose on blood glucose and insulin levels and carbohydrate utilization in man. The experiment was performed by means of continuous indirect calorimetry in five groups of five to six normal volunteers during infusion of either glucose, fructose, sorbitol, xylitol or a mixture of fructose, glucose and xylitol in the proportion of 2:1:1. Glucose and insulin did not present any important variations during the fructose, sorbitol and xylitol infusiosns. However, carbohydrate oxidation rose significantly during administration of these substrates. Carbohydrate oxidation rose 80 mg/min for fructose, 27 mg/min for sorbitol, 39 mg/min for xylitol and 75 mg/min for the carbohydrate mixture, in comparison to 101 mg/min for glucose. It is concluded that fructose, sorbitol and xylitol provoke an increase in carbohydrate utilization without a corresponding rise in glycemia and insulinemia.     

Duodenal xanthine oxidase (EC 1.2.3.2) and ferroxidase activities in the rat in relation to the increased iron absorption caused by peroral xylitol

The effect of peroral administration of xylitol on the absorption of iron and the activities of xanthine oxidase (EC 1.2.3.2) and ferroxidase in rat duodenal wall was studied. Adult male rats were given the basal diet containing 200 g xylitol/kg or the same diet containing no added carbohydrates for 8 weeks. Both feeding groups comprised twelve animals. Xylitol significantly increased serum and liver Fe concentrations with a concomitant, significant increase in the duodenal xanthine oxidase activities, but caused a marginal increase in the duodenal ferroxidase activities. In vitro, sugar alcohols reduced the binding rate of Fe to transferrin. The xylitol-induced increase of Fe absorption may involve the following mechanism: the high intraluminal xylitol concentration of the xylitol-fed rats keeps Fe in the form of a soluble complex for a prolonged period of time, due to the slow absorption of xylitol. The polyol-Fe complex in turn induces xanthine oxidase and ferroxidase formation.     

Plasma levels of d-norgestrel after oral administration

Peripheral plasma levels of d-norgestrel were determined by radioimmunoassay in five women after oral administration of 30, 250 and 1000 μg d-norgestrel. Peak levels of d-norgestrel in plasma were mostly seen within 2 hours after intake of the pills. The peak concentrations found were 0.9–2.0 ng/ml, 3.3–5.1 ng/ml and 14.0–23 ng/ml, respectively, for the three doses administered. The plasma concentrations of d-norgestrel 24 hours after ingestion of the pills were 0.05–0.14 ng/ml, 0.3–0.7 ng/ml and 1.8–5.2 ng/ml, respectively.The plasma half-life of d-norgestrel for the period 8–24 hours following the tablet intake was around 13 hours but varied considerably among the participants. For the period 24–72 hours the corresponding half-life was around 21 hours.During 3 weeks treatment with combined oral contraceptives containing d-norgestrel and ethinyl estradiol, increasing d-norgestrel levels in plasma were found in most of the subjects. Patients on low dose gestagen pills (30 μg d-norgestrel) showed constant plasma levels of d-norgestrel throughout a treatment period of 3 weeks.The results obtained in this study suggest that the gradual increase of the d-norgestrel levels found in plasma when d-norgestrel is given in combination with ethinyl estradiol might be due to increased levels of sex hormone binding globulin, the carrier protein for d-norgestrel, rather than to accumulation caused by a long biological half-life.     

Effect of ethanol administration on plasma glycerol levels in the rat.

Many mechanisms have been postulated as being responsible for the fatty liver resulting from ethanol ingestion. Lipid mobilization has been strongly implicated in both acute and chronic ethanol administration--the difference between the two lying in the source of the fat. In the acute situation, the lipid is mobilized from depot fat, whereas in the chronic situation, it apparently comes from the diet. One possibility not explored is the mobilization of glycerol. This substance is the backbone of triglyceride. Hence, an influx of glycerol to the liver coupled with increased amounts of fatty acids could help explain, in part, the fatty liver resulting from alcohol administration. The purpose of the following study was to determine if such an effect does occur.     

The effect of fasting on enzyme levels in the enlarged and involuting rat pancreas

1. The effect on pancreatic digestive enzyme levels of fasting and changes from a diet containing trypsin inhibitor (raw soya-bean flour, RSF) to diets free of trypsin inhibitor (heated soya-bean flour, HSF, or commercial rat chow) was studied in rats for up to 7 d. 2. In RSF-fed rats killed without fasting, enzyme levels were low, but after fasting for 24 h before killing there was a marked increase in all enzyme levels. Histological studies showed that pancreatic acinar cells from RSF-fed rats killed without fasting were devoid of zymogen granules, but following a 24 h fast there was a marked accumulation of zymogen granules which extend into the basal cytoplasm. Fasting either produced no change or a fall in enzyme levels in rats fasted after feeding HSF or chow continuously. 3. If animals fed on RSF were changed to HSF and either fed or fasted for 24 h up to the time of killing there was an increase in amylase (EC 3.2.1.1), trypsin (EC 3.4.21.4), lipase (triacylglycerol lipase; EC 3.1.1.3) and protein 1 d after the change, followed by a fall over the next 6 d to levels similar to those seen in rats fed on HSF continuously. 4. Animals changed from RSF to chow showed similar effects as far as trypsin, lipase and protein were concerned, but amylase rose, to reach the level seen in rats fed on chow continuously (about ten times that seen in soya-bean-fed rats), after 2 d. 5. These results suggest that in the rats fed on RSF, pancreatic enzyme synthesis is rapid but secretion is equally rapid and intracellular enzyme levels are low. When these animals are fasted or changed to a diet free of trypsin inhibitor the rate of secretion falls but the high rate of synthesis continues for at least 24 h and enzymes accumulate in the pancreas. In studies of pancreatic enzyme levels in rats fed on trypsin inhibitor the extent of fasting before killing the animal is therefore an important variable. Such animals should probably not be fasted before study.     

Toxicity and tissue levels in the rat and guinea pig following acute hexachlorobenzene administration

Summary DDT injected intraperitoneally into black surfperch caused substantial increases in plasma osmotic concentration only at doses much larger than are likely to be encountered in nature. Increased plasma concentrations were below those tolerated by fish adapted to high salinities. Death of marine teleosts from DDT poisoning probably involves factors other than simply osmoregulatory failure.     

Comparison of blood toluene levels after inhalation and oral administration

The purpose of this investigation was to compare blood toluene levels in Sprague-Dawley rats after oral and inhalation administration. Groups of 30 rats were dosed by gavage with 86.7, 217, 433, or 867 mg toluene/kg body wt or exposed for up to 6 hr, 5 rats per exposure, to an atmosphere of either 200 or 1000 ppm toluene. Blood was sampled by cardiac puncture from 5 rats in each of the six dose groups at 0.5, 1.0, 2.0, 4.0, 6.0, and 24.0 hr after gavage dosing or the beginning of the inhalation exposure. Blood toluene levels were analyzed. A four-parameter model was fitted to the blood toluene levels of the orally dosed rats. The area under the curve generated by this model, representing total blood toluene concentration over 6 hr, was calculated and compared to the area under the blood toluene curve for the 6-hr inhalation exposure. Integrated areas from the two routes of exposure were used for direct comparison of oral and inhalation exposures. The data demonstrate that gavage dosing can be used to approximate inhalation exposure to toluene.     

Effect of sodium fluoride mouth rinses containing xylitol and sorbitol on the number of Streptococcus mutans from human saliva]

The objective of this study was to assess the effect of 0.05% sodium fluoride solutions containing 2.5% or 12.5% xylitol on the number of Streptococcus mutans in the human mouth. Fifty boys between 8 and 16 years of age participated in this double-blind crossover study. Of the original 50 boys, 33 finished the study. Participants were randomly divided into four groups. The following solutions were employed: placebo solution; 0.05% sodium fluoride solution; 0.05% sodium fluoride + 2.5% xylitol + 2% sorbitol; 0.05% sodium fluoride + 12.5% xylitol + 2% sorbitol. Each solution was used for a 28-day period (20 mL/day, twice a day), with a 10-day washout period between solutions. There were no significant differences (P = 0.32) between the two xylitol-containing solutions (2.5% vs. 12.5%) concerning the number of Streptococcus mutans. However, there was a significant difference between these two xylitol-containing solutions and the sodium fluoride and placebo solutions (P < 0.001). Our results suggest that the 0.05% sodium fluoride solutions containing either 2.5% or 12.5% xylitol caused a significant reduction in the number of Streptococcus mutans.