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PubMed2001

Five-week intake of short-chain fructo-oligosaccharides increases intestinal absorption and status of magnesium in postmenopausal women.

Fermentable carbohydrates have been shown to be nondigestible by human enzymes in the small intestine but are fermented extensively in the large bowel to short-chain fatty acids (SCFAs), which can increase mineral absorption. It has been shown that feeding such carbohydrates including short-chain fructo-oligosaccharides (sc-FOSs) increases intestinal magnesium (Mg) absorption in animals, but their beneficial impact on Mg absorption in humans still remains to be established. Therefore, this work aimed to investigate the effect of moderate daily doses of sc-FOSs (10 g/day) on the intestinal absorption and status of Mg in postmenopausal women without hormone replacement therapy (HRT). Eleven healthy postmenopausal women aged 59 +/- 6 years (mean +/- SD) received for 5 weeks sc-FOS or sucrose (placebo) treatments according to a randomized, double-blind, crossover design separated by a washout period of at least 3 weeks. Subjects ingested 87.5 mg of stable isotope 25Mg together with a fecal marker. Subsequently, feces were collected for 5-7 days. An inductively coupled plasma mass spectrometer (ICP/MS) was used for 25Mg stable isotope measurements in feces, urine, and blood. Mg levels were assessed also at the beginning and at the end of each treatment in plasma, erythrocytes, and urine. These measurements allowed for the determination of net intestinal Mg absorption and Mg status. The results show that the addition of 10 g sc-FOS to the diet increased Mg absorption by 12.3%, from 30.2 +/- 5.0% (placebo treatment) to 33.9 +/- 7.2% (sc-FOS treatment; mean +/- SD; p < 0.02). This increase in intestinal Mg absorption was accompanied by an increase in plasma 25Mg level and led to a higher urinary 25Mg excretion. This is the first time that such an effect is shown in humans. The overall conclusion of this work is that the ingestion of moderate doses of sc-FOS did improve intestinal Mg absorption and status in postmenopausal women. Because of the important role of Mg in many cellular functions, such Mg absorption improvement may be particularly interesting when the dietary intake of Mg is limited.

Aged↗
PubMed1988

Influence of digestive secretions and food on intestinal absorption of nicardipine.

The role of digestive absorption in the pharmacokinetics of nicardipine has been studied by the perfusion technique. Nicardipine (40 mg) was perfused in six healthy subjects at 5 ml/min for 2 h either in isotonic saline with (Experiment A) or without (B) an occlusive balloon isolating the test segment from digestive secretions, or in a nutrient solution (Experiment C). In Experiments A and B, 100% of nicardipine was absorbed from the jejunal lumen in a 25 cm test segment and in Experiment C it was slightly lower (94%). There was no relationship between the absorption of nicardipine and water movement or bile salt concentration in the jejunum. Nicardipine was already present in the first plasma sample taken after 15 min and the peak level was found at the end of the perfusion. The areas under the curves differed widely between subjects, because of interindividual variation in the first pass effect, but they were similar in Experiments A, B and C. The experimental data showed a good fit to a mode involving a two-phase absorption process. The first phase was associated with intestinal perfusion (zero order process) and the second with passage across the intestinal wall (1st order process). In three further healthy subjects, nicardipine in saline was perfused in the jejunum and then in the ileum on consecutive days. Mean plasma levels over time were similar. The study showed that absorption of nicardipine both from the jejunum and the ileum was complete and was especially rapid. The food-induced change in the kinetics of absorption from the jejunum was too small to affect the pharmacokinetic parameters of nicardipine.

Adult↗
PubMed1984

Non-enhancement of sodium cromoglycate intestinal absorption by quaternary ammonium ions. An effect of salt on ion-pair formation?

Studies on the nature of rat small intestine perfusates indicate that this environment is thermodynamically unfavourable for the production of ion pairs between cromoglycate and alkylbenzyldimethylammonium ions. This is suggested as being the reason why, unlike previously found for ocular absorption of cromoglycate, these quaternary ammonium ions do not alter cromoglycate intestinal absorption.

Animals↗
PubMed1996

Intestinal absorption of strontium chloride in healthy volunteers: pharmacokinetics and reproducibility.

1. The absorption kinetics of orally administered strontium chloride and its reproducibility were investigated in healthy volunteers after administering strontium either under fasting conditions (study I, n = 8) or in combination with a standardized meal (study II, n = 8). Each subject received strontium orally at day 0, 14, and 28 and intravenously at day 42. The study was performed as part of a project in which a simple clinical test for measuring intestinal calcium absorption is being developed, based on the use of stable strontium as a marker. 2. Plasma strontium concentration-time curves were analysed by noncompartment analysis and a four compartment disposition model. Within a volunteer each oral curve was fitted simultaneously with the intravenous curve, by which means a two segment model for absorption was revealed. 3. Mean absolute bioavailability of strontium was 25% without a meal and 19% with a meal, whereas the intraindividual variation was 24% and 20%, respectively. 4. Various limited sampling absorption parameters were determined in order to select a potential test parameter for measuring intestinal calcium absorption using strontium as a marker. Fractional absorption at 4 h (Fc240), obtained after co-ingestion of strontium with a meal, appeared to be the best test parameter, because it represented bioavailability well (r = 0.90).

Administration, Oral↗
PubMedDate not supplied

[Effect of varying vitamin D status in the body on intestinal absorption and metabolism of vitamin D in the rat liver].

The absorption of [3H]-vitamin D3 in the intestine and its hydroxylation in the liver were higher in vitamin D-deficient rats than in vitamin D-treated ones. The higher is the vitamin content in the organism, the greater part of the label is occupied by unchanged vitamin D3. It is supposed that both absorption of the vitamin in the intestine and its 25-hydroxylation in hepatocytes may decrease with a rise of the vitamin D3 amount. This activates a mechanism of protection from the vitamin D redundancy.

Animals↗
PubMed1981

Lactose facilitates the intestinal absorption of lead in weanling rats.

The milk sugar lactose is known to facilitate calcium absorption and has been shown to enhance the uptake of essential trace metals from the intestines as well. Its physiological role as the major carbohydrate source for suckling mammals is thus complemented by its ability to facilitate the absorption of necessary minerals. The studies reported here show that the intestinal absorption of lead and its uptake into blood, liver, kidney, and bone are also increased by lactose in young weanling rats. These data extend the known range of lactose facilitation of mineral absorption to a nonessential, toxic element, confirming the nonspecificity of its action on the gut. In addition, they suggest an explanation for some of the conflicting evidence regarding the prophylactic efficacy of milk in lead poisoning.

Age Factors↗
PubMed1999

Effect of pentobarbital anaesthesia on intestinal absorption and hepatic first-pass metabolism of oxacillin in rats, evaluated by portal-systemic concentration difference.

The effects of anaesthesia on intestinal drug absorption and hepatic first-pass metabolism in rats were investigated by observing the difference in the drug concentration between portal and systemic bloods. Oxacillin and pentobarbital were selected as a model drug and as an anaesthetic, respectively. Rats were divided into a conscious control group and an anaesthetized group. All rats were cannulated simultaneously in the portal vein and in the femoral artery, and oxacillin was orally administered after its intra-arterial injection (double dosing). For the anaesthetized group, pentobarbital was intrasubcutaneously administered twice, first before intra-arterial injection and again before oral administration of oxacillin. The arterial blood alone was sampled from the cannula in the femoral artery before oral administration, whereas the arterial and portal bloods were simultaneously sampled from both cannulated sites after oral administration. Oxacillin concentrations in plasma were assayed by HPLC. The anaesthesia increased the absolute bioavailability (F), the mean absorption time (MAT) and the hepatic recovery ratio (F(H)), but caused little change in the local absorption ratio into the portal system (Fa) and the total clearance (CL). The hepatic clearance (CL(H)) was significantly decreased, resulting in an apparent small change in CL-CL(H) which is considered to be renal clearance. By this method, it was shown directly that an increase in F due to pentobarbital anaesthesia was attributable to the significant increase in F(H). It is expected that the method is useful not only to evaluate the effect of anaesthesia on the first-pass effect, but also to assess the effect of co-administration of drugs on first-pass metabolism.

Anesthesia↗
PubMed1983

Intestinal absorption of fatty acids, and blood lipid composition in sheep.

Interrelationships between intestinal uptake of fatty acids and their concentrations in lipids of blood plasma of sheep were assessed by quantities of individual fatty acids that flowed through and were absorbed from the intestinal tract under different dietary conditions. Major long-chain fatty acids were approximately 90% digested, thus demonstrating that dietary fatty acids of high melting points can be absorbed efficiently by ruminants provided they are well dispersed. Relationships were linear between uptakes of 16:0, 18:0, 18:1, and 18:2 fatty acids from the gut and their concentrations in both triglycerides and triglyceride-free plasma lipids. The proportion of each transferred to triglyceride-free plasma lipids was in order 18: 2 greater than 18:1 greater than 16:0 greater than 18:0, whereas in plasma triglycerides the order was 16:0 = 18:0 = 18:2 less than 18:1. Interconversion of 18:0 to 18:1 by intestinal mucosa may explain the anomalous behavior of 18:1 triglycerides. These results are consistent with the hypothesis that the intrinsic nature of the fatty acid primarily determines the composition of triglyceride-free plasma lipids whereas the relative amount of each acid absorbed by the intestine determines that of plasma triglycerides and, hence, of milk and depot fats of ruminants.

Animals↗

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