Non-haem iron availability from pork meat: Impact of heat treatments and meat protein dose.

Pork meat heated at 60, 80, 100, and 120°C (1h), raw pork meat, BSA, casein and haemoglobin were examined for their effects on in vitro iron availability measured as Fe(2+)-dialysability, and on iron-reducing capacity following in vitro protein digestion (IVPD-dialysis). The pepsin-digested samples of meat heated at 80, 100, and 120°C resulted in increased in vitro iron availability. Generally, the capacity to reduce Fe(3+) to Fe(2+) was higher in the pepsin digests, whereas Fe(2+) decreased significantly after pepsin+pancreatin digestion and only part of the Fe(2+) was dialysable. Regardless of protein concentration, casein had no effect on in vitro iron availability, while pork meat protein treated at 120°C showed dose dependency reaching a plateau at 50mg protein/ml. In conclusion, the major effects on iron availability in vitro was shown in pepsin digests under conditions mimicking those in the duodenal lumen and heat-treatment of meat at 120°C showed the most pronounced effects.

Fish oil feeding is associated with an increased accumulation of dietary lipids in enterocytes: results from an in vivo study in rats.

BACKGROUND: Chronic fish oil consumption is associated with reduced postprandial lipaemia, but the mechanism behind this effect is not fully understood. We studied whether lipid absorption might be altered in rats fed fish oil. METHODS: Male Wistar rats were fed fish oil enriched chow (n = 6) or control oil enriched chow (n = 6). After 4 weeks, 61 mg 3H-triolein was instilled into duodenal tied-off loops. Intestinal segments were removed after 15, 30, 45, 60 and 90 min. Enterocytes were then isolated by calcium chelation and quantified by DNA determination. Non-absorbed 3H-lipid and 3H-lipid contents of enterocytes were determined by liquid scintillation counting. Two other groups of rats (2 x 6) fed the experimental diets were given an oral fat load and fasting and postprandial blood samples were taken. RESULTS: The accumulation of 3H-lipids in enterocytes was higher in rats fed fish oil than in controls (area under the 3H-lipid time curve: 1041.3 versus 670.3 nmol oleic acid x min/microg DNA, P < 0.05). Separation of lipids showed that an accumulation of triglycerides and free fatty acids occurred in rats fed fish oil. The amount of non-absorbed 3H-lipid tended to be higher in the fish oil fed rats (P > 0.1). It was confirmed that the fish oil enriched chow caused lower postprandial lipaemia (34% reduction in serum triglyceride concentrations, P < 0.05). CONCLUSION: Attenuated postprandial lipaemia following fish oil feeding is explained, at least partly, by a transient lipid accumulation in enterocytes which may result in a delayed triglyceride efflux from the enterocytes into the circulation.

Effects of topical ropivacaine on eicosanoids and neurotransmitters in the rectum of patients with distal ulcerative colitis.

BACKGROUND: Topical administration of lidocaine has been suggested to have beneficial clinical effects in patients with active ulcerative colitis, but the mechanism of action, if any, remains obscure. As local anaesthetics may exert anti-inflammatory actions through their inhibition of nervous reflexes, we have studied the local effects of a single rectal dose of ropivacaine gel on rectal concentrations of eicosanoids and neurotransmittors in patients with relapsing ulcerative colitis. METHODS: In a randomized, double-blind, placebo-controlled study, concentrations of leukotriene B4, thromboxane B2 and prostaglandin E2 in rectal dialysates and concentrations of substance P, neurokinin A, somatostatin, vasoactive intestinal polypeptide and calcitonin gene-related peptide in rectal biopsies from 19 patients with active, distally located, ulcerative colitis were measured before and after rectal administration of a 200-mg dose of ropivacaine- or placebo-gel by use of radioimmunoassays. For comparison with normal conditions, concentrations of neuropeptides were measured in another 19 patients with relapsing ulcerative colitis and 14 controls with non-inflamed colon. RESULTS: No significant changes in concentrations of eicosanoids or neuropeptides were observed after ropivacaine or placebo administration. Baseline concentrations of all neuropeptides, except somatostatin, were significantly lower in active ulcerative colitis than in controls with non-inflamed colon. CONCLUSIONS: These findings reveal no evidence of anti-inflammatory actions by ropivacaine in active ulcerative colitis and thus provide no rationale for topical treatment with local anaesthetics.

Regiospecific analysis of neutral ether lipids by liquid chromatography/electrospray ionization/single quadrupole mass spectrometry: validation with synthetic compounds.

A reversed-phase high-performance liquid chromatography (HPLC) method with on-line electrospray ionization/collision-induced dissociation/mass spectrometry (ESI/CID/MS) is presented for the regiospecific analysis of synthetic reference compounds of neutral ether lipids. The reference compounds were characterized by chromatographic retention times, full mass spectra, and fragmentation patterns as an aid to clarify the regiospecificity of ether lipids from natural sources. The results clearly show that single quadrupole mass spectroscopic analysis may elucidate the regiospecific structure of neutral ether lipids. Ether lipid reference compounds were characterized by five to six major ions in the positive ion mode. The 1-O-alkyl-sn-glycerols were analyzed as the diacetoyl derivative, and showed the [M - acetoyl](+) ion as an important diagnostic ion. The diagnostic ions of directly analyzed 1-O-alkyl-2-acyl-sn-glycerols and 1-O-alkyl-3-acyl-sn-glycerols were the [M - alkyl](+), [M + H - H(2)O](+) and [M + H](+) ions. Regiospecific characterization of the fatty acid position was evident from the relative ion intensities, as the sn-2 species had relatively high [M + H](+) ion intensities compared with [M + H - H(2)O](+), whereas the reverse situation characterized the sn-3 species. Furthermore, corresponding sn-2 and sn-3 species were separated by the chromatographic system. However, loss of water was promoted as fatty acid unsaturation was raised, which may complicate interpretation of the mass spectra. The diagnostic ions of directly analyzed 1-O-alkyl-2,3-diacyl-sn-glycerols were the [M - alkyl](+), [M - sn-2-acyl](+) and [M - sn-3-acyl](+) ions. Regiospecific characterization of the fatty acid identity and position was evident from the relative ion intensities, as fragmentation of the sn-2 fatty acids was preferred to the sn-3 fatty acids; however, loss of fatty acids was also promoted by higher degrees of unsaturation. Therefore, both structural and positional effects of the fatty acids affect the spectra of the neutral ether lipids. Fragmentation patterns and optimal capillary exit voltages are suggested for each neutral ether lipid class. The present study demonstrates that reversed-phase HPLC and positive ion ESI/CID/MS provide direct and unambiguous information about the configuration and identity of molecular species in neutral 1-O-alkyl-sn-glycerol classes.

A simplified method for determination of radioactive iron in whole-blood samples.

For studies on iron absorption in man radioisotopes represent an easy and simple tool However, measurement of the orbital electron emitting radioiron, 55Fe, in blood is difficult and insufficiently described in the literature. The present study describes a relatively simple method for simultaneous determination of 55Fe and 59Fe in blood, using a dry-ashing procedure and recrystallization of the remaining iron. The detection limit of the method permits measurements of 0.1 Bq/ml blood thus allowing detection of less than 1% absorption from a 40 kBq dose, which is ethically acceptable in humans. The overall recovery of radioiron from blood is more than 90%, and the coefficient of variation, as judged by the variation in the ratio 55Fe/59Fe is in the order of 4%. Combined with whole-body counting of 59Fe and direct gamma-counting of 59Fe on blood samples, this method represents a sensitive method for studying the intestinal absorption of 55Fe and 59Fe in man and at the same time allows estimation of the amount of radioiron located in the vascular compartment.

Green tea or rosemary extract added to foods reduces nonheme-iron absorption.

BACKGROUND: Phenolic compounds act as food antioxidants. One of the postulated mechanisms of action is chelation of prooxidant metals, such as iron. Although the antioxidative effect is desirable, this mechanism may impair the utilization of dietary iron. OBJECTIVE: We sought to determine the effect of phenolic-rich extracts obtained from green tea or rosemary on nonheme-iron absorption. DESIGN: Young women aged 19-39 y consumed test meals on 4 separate occasions. The meals were identical except for the absence (meal A) or presence (meal B) of a phenolic-rich extract from green tea (study 1; n = 10) or rosemary (study 2; n = 14). The extracts (0.1 mmol) were added to the meat component of the test meals. The meals were extrinsically labeled with either 55Fe or 59Fe and were consumed on 4 consecutive days in the order ABBA or BAAB. Iron absorption was determined by measuring whole-body retention of 59Fe and the ratio of 55Fe to 59Fe activity in blood samples. RESULTS: The presence of the phenolic-rich extracts resulted in decreased nonheme-iron absorption. Mean (+/-SD) iron absorption decreased from 12.1 +/- 4.5% to 8.9 +/- 5.2% (P < 0.01) in the presence of green tea extract and from 7.5 +/- 4.0% to 6.4 +/- 4.7% (P < 0.05) in the presence of rosemary extract. CONCLUSION: Phenolic-rich extracts used as antioxidants in foods reduce the utilization of dietary iron.

Determination of neutral lipid hydroperoxides by size exclusion HPLC with fluorometric detection. Application to fish oil enriched mayonnaises during storage.

A fast (12 min) high-performance size exclusion chromatography (HPSEC) method for the separation of neutral lipid class hydroperoxides in the oil phases from fish oil enriched mayonnaises was developed. Detection and quantification were performed using the postcolumn fluorometric (FL) diphenyl-1-pyrenylphosphine oxidation principle. The reproducibilities judged by intra- and inter-assay variations were 0.64 and 7.2%, respectively. The HPSEC-FL method was applied to assess the effect of supplementations with emulsifier, gallic acid, and EDTA on the oxidative processes in the mayonnaises during storage. Substantial amounts of hydroperoxy triacylglycerols (TAGOOH) and cholesterol esters (CEOOH), together with traces of TAGOOH-dimers, were detected. All supplementations significantly decreased the levels of TAGOOH and to a lesser degree CEOOH. Supplementations with EDTA and gallic acid resulted in constant and slightly increasing levels of TAGOOH, respectively, thus affecting the oxidation mechanisms seen in reference mayonnaise. The emulsifier Panodan TR DATEM reduced the levels of TAGOOH as compared to the appropriate controls.

Reappraisal of bicarbonate secretion by the human oesophagus.

BACKGROUND AND AIMS: Administration of omeprazole to healthy volunteers was recently reported to increase proximal duodenal mucosal bicarbonate secretion. As human oesophagus also secretes bicarbonate, the hypothesis was tested that omeprazole may stimulate oesophageal bicarbonate secretion and thus contribute to the therapeutic efficacy of the drug in gastro-oesophageal reflux disease. SUBJECTS AND METHODS: In nine healthy volunteers, oesophageal "steady state" perfusion of a 10 cm open segment of distal oesophagus was performed twice in random order. The volunteers were pretreated with either 60 mg/day omeprazole for three days and 80 mg intravenous omeprazole before perfusion or 600 mg/day ranitidine for three days and 50 mg/h intravenously during the perfusion. Saliva and samples of aspirate from the perfused oesophagus and stomach were collected and bicarbonate concentrations were measured. RESULTS: The median rates (95% confidence intervals) of intrinsic oesophageal bicarbonate secretion, corrected for contaminating salivary and gastric bicarbonate, were 89 (33-150) and 121 (63-203) mumol/h/10 cm (p > 0.5) in omeprazole and ranitidine treated subjects respectively. Salivary and gastric bicarbonate contaminating the oesophagus accounted for 14% and 3%, respectively, of total oesophageal bicarbonate output. CONCLUSIONS: Bicarbonate secretory capacity of the human oesophagus is less than previously assumed, and the clinical relevance of intrinsic oesophageal bicarbonate for mucosal defence may be overestimated. As omeprazole and ranitidine did not affect bicarbonate secretion differently there was no evidence that omeprazole acts on bicarbonate secretory cells in the oesophageal mucosa.

Acute effects of high-dose intragastric nicotine on mucosal defense mechanisms: an analysis of nicotine, prostaglandin E2, phospholipase A2, and phospholipids.

Peptic ulcer disease is overrepresented among smokers; they also heal slowly and relapse frequently. Data are accumulating that smoking is detrimental to gastroduodenal mucosal cytoprotection. This study was designed to assess acute effects of high-dose intragastric nicotine, as it has been shown that nicotine is accumulated in gastric juice when smoking. Seven healthy smokers were given nicotine base (6 mg) as tablets, which yielded very high intragastric concentrations and plasma levels comparable to those seen when smoking. In addition to nicotine analysis, concentration levels of prostaglandin E2 (PGE2), phospholipase A2 (PLA2), and phospholipid classes were measured before and after nicotine administration. Nicotine inhibited PGE2 levels by 27-81%, whereas PLA2 and total phospholipids were unaffected. Lysolecithin, a degradation product of the main constituent of gastric surfactant, ie, phosphatidylcholine, tended to increase, but this was not reflected in intragastric phosphatidylcholine levels. In conclusion, nicotine acutely inhibits PGE2 and may thus impair mucosal cytoprotection. The present findings do not imply a central role of surface-active phospholipids with respect to nicotine and gastric cytoprotection, but the chronic effects of nicotine remain to be investigated.

Omeprazole promotes proximal duodenal mucosal bicarbonate secretion in humans.

The proton pump inhibitor, omeprazole, surprisingly resulted in higher rates of proximal duodenal mucosal bicarbonate secretion than previously reported using an H2 receptor antagonist for gastric acid inhibition. Gastroduodenal perfusions were performed in healthy volunteers to evaluate whether this incidental finding is explained by more potent gastric acid inhibition by omeprazole or might be caused by the different mode of drug action. Basal and stimulated gastric and duodenal bicarbonate secretion rates were measured in the same subjects in control experiments (n = 17) and after pretreatment with high dose omeprazole (n = 17) and ranitidine (n = 9), respectively, by use of a technique permitting simultaneous measurements. Concentrations of bicarbonate were measured in the respective effluents by the method of back titration. Both omeprazole and ranitidine completely inhibited gastric acid secretion (pH 6.9 v 6.8; p > 0.05). Omeprazole caused higher rates of basal (mean (SEM)) (597 (48) v 351 (39) mumol/h; p < 0.02) and vagally stimulated (834 (72) v 474 (66) mumol/h; p < 0.02), but not acid stimulated (3351 (678) v 2550 (456) mumol/h; p > 0.05) duodenal bicarbonate secretion compared with control experiments. Also the combination of omeprazole and ranitidine increased (p = 0.05) duodenal bicarbonate secretion, while ranitidine alone caused no change in either basal or stimulated secretion. In the stomach basal as well as vagally stimulated bicarbonate secretion was independent of the means of acid inhibition. These results show that the proton pump inhibitor, omeprazole, promotes proximal duodenal mucosal bicarbonate secretion apparently independent of its gastric acid inhibitory effect. The mechanism of action remains speculative.

Gastric bicarbonate secretion and release of prostaglandin E2 are increased in duodenal ulcer patients but not in Helicobacter pylori-positive healthy subjects.

BACKGROUND: Duodenal ulcer (DU) patients have impaired proximal duodenal mucosal bicarbonate secretion at rest and in response to luminal acid with higher acid-stimulated mucosal release of prostaglandin (PG) E2 than healthy subjects. Our purpose was to determine whether this abnormality was present also in the stomach of DU patients. METHODS: Simultaneous determinations of gastric and duodenal bicarbonate secretion and luminal release of PGE2 were performed in 16 healthy volunteers (5 Helicobacter pylori-positive) and 8 inactive DU patients (all H. pylori-positive). RESULTS: In healthy volunteers the rates of gastroduodenal bicarbonate secretion and the release of PGE2 were not influenced by H. pylori status. In inactive DU patients the rates of basal (704 +/- 84 versus 356 +/- 40 mumol/h; mean +/- SEM) and vagally stimulated (modified sham feeding) (1724 +/- 376 versus 592 +/- 52 mumol/h) gastric bicarbonate secretion were higher (p < 0.05) than in the health, whereas the corresponding rates (339 +/- 42 versus 591 +/- 51 mumol/h and 543 +/- 99 versus 778 +/- 69 mumol/h) in duodenal bicarbonate secretion were lower (p < 0.05). In addition, inactive DU patients had higher basal (148 +/- 32 versus 53 +/- 5 ng/h) and stimulated (291 +/- 84 versus 131 +/- 25 ng/h) gastric release of PGE2, but only the basal release of PGE2 into the duodenum was significantly increased (20 +/- 3 versus 5 +/- 1 ng/h; p < 0.05). CONCLUSION: Increased mucosal production of PGE2 may be responsible for the abnormally high gastric secretion of bicarbonate in inactive DU patients. The defective duodenal secretion of bicarbonate observed in these patients may be a consequence of previous ulceration rather than the mere presence of H. pylori infection.

Selective blockade of leukotriene production by a single dose of the FPL 64170XX 0.5% enema in active ulcerative colitis.

5-Lipoxygenase products of arachidonic acid metabolism are thought to play a central role in the secondary amplification of the inflammatory response of several inflammatory diseases, including ulcerative colitis. FPL 64170XX is a selective inhibitor of the enzyme 5-lipoxygenase. Concentrations of leukotriene B4 and prostaglanding E2 in rectal dialysis fluid from 23 males with clinically and sigmoidoscopically active, distally located ulcerative colitis were measured by radioimmunoassays in a double-blind, placebo-controlled, parallel design study before and after rectal administration of an enema containing 0.5% of FPL 64170XX. Repeated measures analysis of leukotriene B4, after adjusting for baseline, showed a significant treatment effect (P = 0.0014). The concentration of leukotriene B4 from rectal dialysates in patients receiving the active drug dropped to 15% (95% confidence interval 5-40%) of the placebo level in the second dialysis following administration of FPL 64170XX 0.5%. By contrast, prostaglanding E2 concentrations doubled (P = 0.0068) in patients receiving FPL 64170XX 0.5% with no change in the placebo group. These findings demonstrate that a single dose of FPL 64170XX 0.5% enema selectively blocks the generation of the 5-lipoxygenase product, leukotriene B4, to a mean of 85% in the target tissue of inflammation. Topical administration of this new leukotriene synthesis inhibitor may prove to be a clinically useful approach to the treatment of active, distally located ulcerative colitis.

Indomethacin decreases gastroduodenal mucosal bicarbonate secretion in humans.

BACKGROUND: Cyclooxygenase inhibitors reduce mucosal bicarbonate secretion in the duodenum, but the evidence for their effect on bicarbonate secretion in the stomach remains controversial. We have, therefore, studied how indomethacin influences gastroduodenal bicarbonate secretion and luminal release of prostaglandin (PG) E2 by means of a method that enables simultaneous measurements in the stomach and the duodenum. METHODS: Gastric and duodenal perfusions were performed twice in random order during control conditions or after pretreatment with indomethacin (100 mg intravenously) in eight healthy volunteers. Bicarbonate and PGE2 were measured in the gastroduodenal effluents by back-titration and radioimmunoassay, respectively. RESULTS: Vagal stimulation and duodenal luminal acidification (0.1 M HCl; 20 ml; 5 min) increased gastroduodenal bicarbonate secretion (p < 0.05). Indomethacin markedly inhibited both basal and stimulated gastric and duodenal mucosal bicarbonate secretion, and this reduction was similar to the degree of cyclooxygenase inhibition estimated by the luminal release of PGE2 (p < 0.05). CONCLUSION: These results unequivocally demonstrate that endogenous PG modulates basal and stimulated bicarbonate secretion, both in the stomach and in the duodenum.

Misoprostol inhibits gastric mucosal release of endogenous prostaglandin E2 and thromboxane B2 in healthy volunteers.

Prostaglandin analogues of the E-series theoretically offer the ideal antiulcer drugs. Peptic ulcer healing with prostaglandin analogues is, however, no better than would be predicted from their ability to inhibit gastric acid secretion and they are less effective than histamine H2 receptor antagonists in preventing ulcer relapse. It could be that prostaglandin analogues inhibit gastric mucosal synthesis or release of endogenous eicosanoids, thereby abrogating their own effects. This study, therefore, examined how a single therapeutic dose (200 micrograms) of misoprostol, a synthetic analogue of prostaglandin E1, influences gastric mucosal release of endogenous prostaglandin E2 (PGE2), thromboxane B2 (TXB2), and chemotactic leukotriene B4 (LTB4) during basal conditions and in response to gastric luminal acidification (0.1 M HCl; 5 ml/min for 10 minutes). Nine healthy volunteers were studied in a single blind, cross over design. In each subject misoprostol or placebo was instilled in randomised order into the stomach, which was subsequently perfused with isotonic mannitol. Misoprostol significantly decreased basal as well as acid stimulated output of PGE2 and TXB2, without affecting output of LTB4. These data show that misoprostol inhibits gastric mucosal synthesis of prostanoids. Decreased concentrations, or even a changed profile, of native eicosanoids modulating the release of inflammatory mediators from immune cells might explain why prostaglandin analogues have a comparatively poor clinical performance in ulcer healing and prevention.

Muscarinic M1 receptor inhibition reduces gastroduodenal bicarbonate secretion and promotes gastric prostaglandin E2 synthesis in healthy volunteers.

The selective muscarinic M1 receptor antagonist, pirenzepine, considerably stimulates duodenal mucosal bicarbonate secretion in the rat and increases gastric luminal release of prostaglandin E2 (PGE2) in humans. This study, therefore, looked at the effect of pirenzepine on bicarbonate secretion and luminal output of PGE2 into the stomach and the duodenum of nine healthy volunteers using a new technique permitting simultaneous measurements. In the stomach modified sham feeding increased bicarbonate secretion from 382 (62) mumol/h (mean (SEM)) to 959 (224) mumol/h (p < 0.02). In the duodenum modified sham feeding and acid exposure (HCl 0.1 M; 20 ml; 5 min) of the duodenal bulb increased mucosal bicarbonate secretion from 191 (14) mumol/cm x h to 266 (27) mumol/cm x h (p < 0.02) and 634 (157) mumol/cm x h (p < 0.01), respectively. Pirenzepine (10 mg/h intravenously) reduced basal and vagally stimulated gastric and basal duodenal bicarbonate secretion by about 50% (p < 0.03). In the stomach, but not the duodenum, basal and vagally stimulated PGE2 output increased significantly (p < 0.05) in response to pirenzepine. In conclusion, human gastroduodenal mucosal bicarbonate secretion is regulated by a pirenzepine sensitive mechanism, which is probably cholinergic. The rise in gastric PGE2 output seen in response to M1 receptor inhibition by pirenzepine suggests the existence of a feed back loop secondary to the decrease seen in bicarbonate secretion.

Blockade of leukotriene production by a single oral dose of MK-0591 in active ulcerative colitis.

BACKGROUND: 5-Lipoxygenase products of arachidonic acid metabolism are thought to play a central role in the secondary amplification of the inflammatory response in a number of human inflammatory diseases, such as ulcerative colitis. MK-0591 (3-(1((4-chlorophenyl)methyl)-3((1,1-dimethyl-ethyl)thio)-5(quinolin+ ++-2ylmethyl-oxy)-1H-indol-2yl)-2,2-dimethyl-propanoate) exerts its effect by binding to the 5-lipoxygenase activating protein, thereby inhibiting the translocation and activation of 5-lipoxygenase. METHODS: Concentrations of leukotriene B4 (LTB4) and prostaglandin E2 (PGE2) in rectal dialysis fluid, ex vivo biosynthesis of LTB4 in whole blood, and urinary excretion of leukotriene E4 (LTE4) from 16 patients with mild to moderately active distally located ulcerative colitis were measured by use of radioimmunoassays in a double-blind, placebo-controlled parallel-design study before and after oral administration of a 250 mg dose of MK-0591 or placebo. RESULTS: The mean LTB4 concentration in rectal dialysis fluid was lowered after MK-0591 by > 90% (p < 0.05) from 4 to 8 hours, with a maximum inhibition of 97.5% +/- 3.4% (mean +/- SD) at 20 to 24 hours after dosing, whereas PGE2 was unchanged. In whole blood, MK-0591 decreased ex vivo biosynthesis of LTB4 (p < 0.01), with a maximum inhibition of 96.4% +/- 2.1% at 4 hours after dosing. Urinary excretion of LTE4 was reduced by more than 85% (p < 0.001) from 4 to 48 hours. No adverse events were observed. CONCLUSION: These findings show that a single oral 250 mg dose of MK-0591 results in nearly complete blockade of systemic leukotriene production and LTB4 formation in the target tissue of inflammation (the rectum). Controlled multiple-dose trials to assess the clinical efficacy of this novel 5-lipoxygenase-activating protein inhibitor seem to be worthwhile.

Failure of tropisetron to inhibit jejunal water and electrolyte secretion induced by 5-hydroxytryptamine in healthy volunteers.

The effects of the 5-hydroxytryptamine (5-HT3) receptor antagonist, ICS 205-930 (tropisetron), on basal and 5-HT induced jejunal secretion of water and electrolytes were examined using a double blind, randomised crossover design. In seven healthy volunteers steady state perfusions of the proximal jejunum were performed twice with the Loc-I-Gut tube after 5+5 mg ICS 205-930 or placebo capsules were given. After equilibration for 60 minutes and completion of a 120 minute basal period 5-HT (10 micrograms/kg x min intravenously) was infused for 120 minutes. Net water absorption (mean (SEM)) in the basal period was 0.55 (0.84) ml/cm x h and 0.74 (0.72) ml/cm x h after placebo and ICS 205-930, respectively (p > 0.05). Infusion of 5-HT caused significant net secretion of water after placebo (2.05 (0.58) ml/cm x h; p < 0.02) as well as ICS 205-930 (2.60 (0.89) ml/cm x h; p < 0.05). As ICS 205-930 excerted no effects on either basal or 5-HT induced water and electrolyte transport in the intact human jejunum the compound is probably not efficacious as an anti-secretory drug in patients with 5-HT induced diarrhoea.