Effects of growth hormone administration on vitamin D metabolism and vitamin D receptors in the pig.

Twelve 36-kg pigs were given either 100 micrograms/kg porcine pituitary growth hormone (pGH) or placebo injections daily for 33 days. Serum was obtained weekly for analysis of minerals and vitamin D metabolites. On day 34, the pigs were sacrificed and renal and duodenal tissue were obtained for analysis of vitamin D receptor content (VDR). Animals treated with pGH grew faster and had a higher rate of bone accretion than did control animals. Serum concentrations of 1,25-dihydroxyvitamin D (1,25-(OH)2D) were significantly higher in pGH-treated pigs than in control pigs at all time points following initiation of treatment, with the greatest difference observed at day 28 (42.4 +/- 4.9 pg/ml in controls vs. 65.4 +/- 4.7 pg/ml in pGH-treated pigs). Serum 24,25-dihydroxy-vitamin D tended to be lower in pGH-treated pigs than in control pigs, being significantly lower on day 21 of the experiment (3.22 +/- .52 vs. 6.73 +/- 1.22 ng/ml, respectively). Serum concentrations of 25-hydroxyvitamin D and calcium were unaffected by pGH treatment. Kidneys of control pigs contained significantly more unoccupied vitamin D receptors than did kidneys from pGH-treated pigs (73.3 +/- 4.3 vs. 58.3 +/- 4.1 fmoles/mg protein). Duodenal tissue unoccupied vitamin D receptor content was similar in both pGH-treated (245 +/- 17.9 fmoles/mg protein) and control (263 +/- 21.8 fmoles/mg protein) pigs. Duodenal occupied vitamin D receptor concentration was similar in both pGH-treated (6.8 +/- .75 fmoles/mg protein) and control pigs (5.32 +/- .77 fmoles/mg protein).(ABSTRACT TRUNCATED AT 250 WORDS)

Fourier analysis of biliary and pancreatic excretion in man based on data obtained by a duodenal perfusion/aspiration technique.

A standard duodenal perfusion/aspiration technique was used to continuously monitor biliary and pancreatic excretion in young healthy human subjects, and the excretory patterns were examined by Fourier power spectral analysis. Experiments were carried out in the fasting state, either without or during a continuous parenteral (i.v.) stimulation by secretin and the cholecystokinin analogue ceruletide. The duodenal content aspirated was either discarded after sampling or reinfused into the jejunum. In the fasting state, significant biliary and pancreatic excretion was detected, fluctuating with a periodicity of about 60 min. During parenteral infusion with ceruletide/secretin, to simulate a postprandial state, the rate of biliary and pancreatic excretion increased as compared with fasting levels alone (basal levels). A dominant period of about 60 min was still detected but second periods of approximately 45 min and approximately 95 min, respectively, were also observed. The peak power and the total power of the biliary excretion signals were reduced. Reinfusion of aspirated duodenal fluid into the intestine (jejunum) led to a further decrease in peak power and total power of the known biliary signals. Trypsin excretion into the duodenum revealed mainly insignificant changes in peak and total power upon hormone stimulation despite a definite increase in total amount of trypsin excreted. The results indicate that parenteral ceruletide/secretin stimulation has a stabilizing effect on biliary excretion in man, and that reinfusion of aspirated duodenal content into the intestine further stabilizes the excretion.

An improved purification procedure for conjugated bile acids using octadecyl-bonded silica cartridges.

A rapid procedure for the extraction of conjugated bile acids from human fluids using pre-packed octadecyl-bonded silica cartridges is described. The method was compared with the other procedures reported in the literature and was found to produce a higher degree of sample purification and to achieve satisfactory accuracy and reproducibility. The present procedure is applicable to the high-performance liquid chromatographic assay of bile acid conjugates in human bile, gastric juice, serum and urine.

Subcellular localization of recently-absorbed iron in mouse duodenal enterocytes: identification of a basolateral membrane iron-binding site.

The subcellular distribution of newly absorbed iron in isolated mouse duodenal enterocytes was investigated by analytical subcellular fractionation using sucrose density gradient centifugation. Two major peaks of mucosal 59Fe activity were observed: one soluble and one particulate (density 1.18-1.20 g ml-1). The latter was increased following prior exposure of animals to chronic hypoxia. The particulate 59Fe was localized to the basolateral membranes using the marker enzyme Na+, K+ activated, Mg2+ dependent, ATPase and by washing intact enterocytes with the selective plasma membrane perturbant digitonin. The basolateral membrane can be selectively labelled by in vitro incubation of intact enterocytes at 0 degrees C with 59Fe(III)-nitrilotriacetate complex, confirming the presence of a 59Fe binding site on this membrane. No significant difference in in vitro iron binding to this site was observed between normal and chronically hypoxic animals. Iron binding to the basolateral membrane was significantly higher in disrupted, compared to intact enterocytes, indicating that this site is present on both sides of the basolateral membrane. It is therefore suggested that the increased labelling of this site in hypoxia, in vivo, is a consequence of an increase in a mucosal Fe pool which is available for binding to a membrane receptor.

Effect of age on duodenal 1,25-dihydroxyvitamin D-3 receptors in Wistar rats.

We confirmed our previous observation that duodenal Ca2+ absorption and serum 1,25-dihydroxyvitamin D (1,25-(OH)2D) levels declined concurrently in old (24 months old) rats as compared to young (6 months old) rats. It is well known that 1,25-dihydroxyvitamin D-3 (1,25-(OH)2D3) expresses its action after binding to specific receptor molecules. In this paper, we compared certain properties of rat duodenal 1,25-(OH)2D3 receptors from old and young animals. Receptor preparations were incubated with [3H]1,25-(OH)2D3 to quantitate the number of unoccupied and total receptor sites and showed that total and unoccupied receptor sites decreased by 22 and 16%, respectively in old rats. Endogenously occupied sites were reduced by 43% in duodenum of the old rat and, consequently, the percentage of receptor occupancy also declined. Age did not affect the dissociation constant (KD) of 1,25-(OH)2D3 from the receptor; the sedimentation coefficient (3.3 S) of the tritiated 1,25-(OH)2D3-receptor complex in sucrose density centrifugation; or its affinity for DNA. The data are consistent with the hypothesis that the age-related decline in Ca2+ absorption in the intestine may be due, in part, to the decrement in the circulating level of 1,25-(OH)2D and a reduction of intestinal 1,25-(OH)2D3 receptor occupancy status.

Bile acid profiles in peroxisomal 3-oxoacyl-coenzyme A thiolase deficiency.

Fast atom bombardment mass spectrometry and gas chromatography-mass spectrometry were used to analyze bile acids in the body fluids of an infant (L.C.) whose liver contained no immunoreactive peroxisomal 3-oxoacyl-CoA thiolase. The profiles were compared with those of six patients with undetectable peroxisomes (Zellweger syndrome) and two siblings (N.B. and I.B.) whose defect of peroxisomal beta-oxidation could not be localized by morphological studies of peroxisomes or by immunoblotting of peroxisomal beta-oxidation proteins. 3 alpha, 7 alpha, 12 alpha-Trihydroxy-5 beta-cholestan-26-oic acid (THCA) was present in bile and plasma of all patients. However, bile from L.C., N.B. and I.B. contained unconjugated varanic acid (3 alpha, 7 alpha, 12 alpha, 24-tetrahydroxy-5 beta-cholestan-26-oic acid) as the major C27 bile acid, whereas bile from Zellweger patients contained only small amounts of varanic acid. In the bile from L.C. two isomers of varanic acid were present; in the bile from N.B. and I.B. a single isomer predominated. L.C., N.B., and I.B. all produced bile containing small amounts of (24E)-3 alpha, 7 alpha, 12 alpha-trihydroxy-5 beta-cholest-24-en-26-oic acid [( 24E]-delta 24-THCA), its [24Z]- isomer, 3 alpha, 7 alpha, 12 alpha-trihydroxy-5 beta-cholest-23-en-26-oic acid and 3 alpha, 7 alpha, 12 alpha-trihydroxy-27-nor-5 beta-cholestan-24-one. The results provide evidence for peroxisomal pathways for cholic acid synthesis in man via THCA, delta 24-THCA and varanic acid and show that bile acid analyses can be used to diagnose peroxisomal thiolase deficiency.

The distribution of galanin message-associated peptide-like immunoreactivity in the pig.

Using a radioimmunoassay (RIA) developed to the N-terminal part of the predicted sequence of porcine galanin message-associated peptide (GMAP), we have confirmed the existence of GMAP-like immunoreactivity (-LI) in normal porcine tissues. GMAP-LI was found to parallel the distribution of galanin-immunoreactivity (-IR), although consistently the concentrations detected were, on a molar ratio, significantly less than those measured for galanin throughout the gastrointestinal tract, brain, spinal cord, adrenal and pituitary gland. As cleavage of the prohormone would be expected to produce galanin and GMAP on an equimolar basis, it is possible that the endogenous, intact GMAP peptide does not fully cross-react with the antibody raised to the N-terminal GMAP sequence. Gel chromatography of tissue extracts revealed a single molecular form of galanin-IR in the gut and four distinct molecular forms in the adrenal gland. GMAP-LI eluted as a single immunoreactive component in the gut, and in the adrenal gland there were two major molecular forms, one of which was apparently also detected by the galanin assay, and a small amount of N-terminal fragment. This molecular heterogeneity seems likely to be a result of the various possible prohormone cleavage products and/or posttranslational processing modifications. Further analysis of the galanin gene products needs to be undertaken in order to confirm this.

An immunohistochemical study of endocrine cells in the proximal duodenum of eight marsupial species.

The proximal duodenum of eight marsupial species, (koala, common brushtail possum, ring-tailed possum, common wombat, great grey kangaroo, parma wallaby, short-nosed bandicoot and tiger cat) were investigated immunohistochemically using 12 specific antisera for gut hormones. Several types of immunoreactive cells were seen on the intestinal villi and in crypts of these species: 9 types in the koala; 8 types in the common brushtail possum; 7 types in the common wombat; 6 types in the short-nosed bandicoot and 5 types in the ringtailed possum, great grey kangaroo, parma wallaby and tiger cat. Gastrin-, somatostatin-, motilin- and serotonin-immunoreactive cells were seen in all species examined. A few BPP-, enteroglucagon-, CCK-, secretin-, GIP- and neurotensin-immunoreactive cells were seen but only in few species. A few substance P-immunoreactive cells were detected only in the koala. Immunoreactive cells were also seen in Brunner's glands: 5 types in the parma wallaby; 3 types in the great grey kangaroo and tiger cat; 2 types in the koala and common wombat; 1 type in the short-nosed bandicoot. No immunoreactive cells were found in Brunner's glands of the common brushtail possum.

Physical-chemical behavior of dietary and biliary lipids during intestinal digestion and absorption. 2. Phase analysis and aggregation states of luminal lipids during duodenal fat digestion in healthy adult human beings.

Following the feeding of a triacylglycerol-rich meal to healthy adult human beings, duodenal contents were aspirated for ex vivo chemical and physical-chemical analyses. The aspirates were collected during established lipid digestion and absorption into a "cocktail" of chemical inhibitors that rapidly inhibited ex vivo lipolysis. Following ultracentrifugation, the lipids separated into a floating oil layer, several interfacial layers, a "clear" or turbid "subphase", and a precipitated "pellet". By chemical and phase analyses, the floating layer was composed of oil-in-water emulsion particles with cores of triacylglycerol (TG), diacylglycerols (DG), and cholesteryl esters (CE) emulsified with a surface coat of partially ionized fatty acids (FA), monoacylglycerols (MG), diacylphosphatidylcholine (PL), and bile salts (BS). The interfacial layers contained similar emulsion particles dispersed among excess emulsifier which adopted a lamellar liquid-crystalline structure. Precipitated pellets were composed principally of emulsifying lipids, with smaller amounts of crystalline calcium soaps and BS. Relative lipid compositions of all but three subphases fell within a two-phase region of the condensed ternary phase diagram (Staggers et al., 1990, companion paper) where saturated mixed micelles composed of BS, FA "acid-soaps", MG, PL, cholesterol (Ch), and traces of DG (and TG) coexisted with unilamellar liquid-crystalline vesicles composed of the same lipids. Attempts to achieve clean separation of vesicles from micelles by repeat ultracentrifugation failed. Compared with the structure and sizes of lipid particles in equilibrated model systems (Staggers et al., 1990), quasielastic light scattering (QLS) analysis revealed that ex vivo micellar sizes (mean hydrodynamic radii, Rh) were similar (less than or equal to 40 A), whereas unilamellar vesicle sizes (Rh = 200-600 A) were appreciably smaller. Two-component QLS analysis of the subphases showed that much larger proportions of lipids were solubilized by micelles than were dispersed as unilamellar vesicles. When followed as functions of time, vesicles frequently dissolved spontaneously into mixed micelles, indicating that, in the nonequilibrium in vivo conditions, the constituent micellar phase was often unsaturated with lipids. These results are consistent with the hypothesis that, during hydrolysis of emulsified DG and TG by luminal lipases, unilamellar vesicles originate in lamellar liquid crystals that form at emulsion-water interfaces in the upper small intestine. In a BS-replete environment, unilamellar vesicles probably represent the primary dispersed product phase of human fat digestion and facilitate the dissolution of lipolytic products into unsaturated mixed micelles.(ABSTRACT TRUNCATED AT 400 WORDS)

Physical-chemical behavior of dietary and biliary lipids during intestinal digestion and absorption. 1. Phase behavior and aggregation states of model lipid systems patterned after aqueous duodenal contents of healthy adult human beings.

We developed equilibrium phase diagrams corresponding to aqueous lipid compositions of upper small intestinal contents during lipid digestion and absorption in adult human beings. Ternary lipid systems were composed of a physiological mixture of bile salts (BS), mixed intestinal lipids (MIL), principally partially ionized fatty (oleic) acid (FA) plus racemic monooleylglycerol (MG), and cholesterol (Ch), all at fixed aqueous-electrolyte concentrations, pH, temperature, and pressure. The condensed phase diagram for typical physiological conditions (1 g/dL total lipids, FA:MG molar ratio of 5:1, pH 6.5, 0.15 M Na+ at 37 degrees C) was similar to that of a dilute model bile [BS/lecithin (PL)/Ch] system [Carey, M. C., & Small, D. M. (1978) J. Clin. Invest. 61, 998-1026]. We identified two one-phase zones composed of mixed micelles and lamellar liquid crystals, respectively, and two two-phase zones, one composed of Ch monohydrate crystals and Ch-saturated micelles and the other of physiologic relevance composed of Ch- and MIL-saturated mixed micelles and unilamellar vesicles. A single large three-phase zone in the system was composed of Ch-saturated micelles, Ch monohydrate crystals, and liquid crystals. Micellar phase boundaries for otherwise typical physiological conditions were expanded by increases in total lipid concentration (0.25-5 g/dL), pH (5.5-7.5), and FA:MG molar ratio (5-20:1), resulting in a reduction of the size of the physiological two-phase zone. Mean particle hydrodynamic radii (Rh), measured by quasielastic light scattering (QLS), demonstrated an abrupt increase from micellar (less than 40 A) to micelle plus vesicle sizes (400-700 A) as this two-phase zone was entered. With relative lipid compositions within this zone, unilamellar vesicles formed spontaneously following coprecipitation, and their sizes changed markedly as functions of time, reaching equilibrium values only after 4 days. Further, vesicle Rh values were influenced appreciably by MIL:mixed bile salt (MBS) ratio, pH, total lipid concentration, and FA:MG ratio, but not by Ch content. In comparison, micellar systems equilibrated rapidly, and their Rh values only slightly influenced by physical-chemical variables of physiological importance. In contrast to the BS-PL-Ch system [Mazer, N. A., & Carey, M. C. (1983) Biochemistry 22, 426-442], no divergence in micellar sizes occurred as the micellar phase boundary was approached. The ionization state of FA at simulated "intestinal" pH values (5.5-7.5) in the micellar and physiologic two-phase zones was principally that of 1:1 sodium hydrogen dioleate, an insoluble swelling "acid soap" compound. By phase separation and analysis, tie-lines for the constituent phase in the two-phase zone demonstrated that the mixed micelles were saturated with MIL and Ch and the coexisting vesicles were saturated with MBS, but not with Ch.(ABSTRACT TRUNCATED AT 400 WORDS)

Intracellular free amino acid patterns in duodenal and colonic mucosa.

We report for the first time the concentrations of free amino acids in human intestinal biopsies obtained by routinely performed endoscopy. We studied 15 medical patients with no changes of the mucosa and six HIV-infected persons with duodenitis. The mean (and SD) sum of all amino acids, taurine excepted, was 61.9 (5.4) mmol/kg dry weight in duodenal biopsies of HIV-negative subjects (n = 11) and 82.9 (0.6) mmol/kg in colonic specimens: 50% (44%) of the total (minus taurine) consisted of aspartate and glutamate and 14% (12%), of the essential amino acids. The relative amino acid pattern in duodenum and colon differed completely from that for muscle: aspartate was fourfold higher; glutamate, phenylalanine, glycine, valine, leucine, and isoleucine were about twofold higher. In contrast, glutamine amounted only to 4% (duodenum) to 14% (colon) of muscle glutamine. In duodenal biopsies of the HIV-infected persons, we found significantly (P less than 0.01, except glutamine: P less than 0.025) increased concentrations of glutamate (24.1 vs 17 mmol/kg dry weight), ornithine (1.4 vs 0.4), valine (2.2 vs 1.7), and glutamine.

[Measurement of secretory IgA in salivary juice and the localization of secretory IgA in duodenal mucosa in patients with IgA nephropathy].

In order to clarify whether or not the local IgA immune system plays a role on the pathogenesis of IgA nephropathy, we measured serum levels of IgA, serum and salivary levels of secretory IgA in patients with IgA nephropathy and in healthy subjects, and compared them with the results of immunohistochemical study of the duodenal mucosa obtained from patients with IgA nephropathy and healthy subjects. The results were as follows. 1. The serum levels of IgA were significantly higher in patients with IgA nephropathy than in healthy subjects. 2. The salivary levels of secretory IgA were significantly higher in patients with IgA nephropathy and non IgA nephropathy than in healthy subjects. 3. There was no significant difference in the serum levels of secretory IgA between patients with IgA nephropathy and healthy subjects, but they were significantly higher in patients with hematuria than without hematuria. 4. The salivary levels of secretory IgA were lower in some patients with IgA nephropathy, in spite of the intense staining of the secretory component and J chain in the duodenal mucosa, than in healthy subjects. On the other hand, the salivary levels of secretory IgA were lower in other patients with IgA nephropathy, in addition to the weak staining of secretory component and J chain in the duodenal mucosa than in healthy subjects. These results suggested that the disorder of IgA mucosal immunity may contribute to the pathogenesis of IgA nephropathy.

Mucin histochemistry of virus-induced duodenal adenomas in guinea fowl.

The type of mucoproteins in virus-induced duodenal adenomas in guinea fowl were compared with those in the normal duodenal mucosa. The mucin-producing cells in the latter contained a mixture of acid and neutral mucins. Neutral and sulphomucins prevailed in the crypts and in the lower part of the villi, while the amount of the sialomucins increased progressively toward the tip of the villi. In the adenomas, goblet cells were more numerous and were unevenly distributed. In their mucin profile the deeply located tumor glandular structures resembled normal crypts and lower parts of the villi and superficial portions of the adenomas were similar to the upper part of the villi. Qualitative changes in the mucin secretion with deviation from the normal vertical distribution of mucin types were rarely observed. The histochemical study carried out supplemented the histological characterization of the virus-induced duodenal adenomas and contributed to the elucidation of some aspects of their histogenesis.

The concentration of dopamine and related monoamines in arteries and some other tissues of the sheep.

1. The highest concentrations of dopamine were observed in the sheep coronary interventricular artery (1.0 micrograms/g) and the lowest in the aorta (0.15 micrograms/g). Varying proportions of noradrenaline was also present in the arteries examined with dopamine:noradrenaline ratios ranging from 0.08 to 1.11. 2. p-Tyramine is the trace amine present in highest concentration in both the lung and the caudate nucleus (21.3 and 10.5 ng/g, respectively) while the levels of beta-phenylethylamine, m-tyramine and tryptamine are lower and range between 1.6 and 4.2 ng/g. 3. The results show that sheep arteries, lung and duodenum contain considerable amount of dopamine that is presumably associated with chromaffin cells. It is most likely that these cells also contain 5-hydroxytryptamine while the localization of trace amines remains to be elucidated.

Assembly of the brush border cytoskeleton: changes in the distribution of microvillar core proteins during enterocyte differentiation in adult chicken intestine.

The assembly of the intestinal microvillus cytoskeleton was examined during the differentiation of enterocytes along the crypt-villus axis in adult chicken duodenum using light and electron microscopic immunolocalization techniques. Using antibodies reactive with villin, fimbrin, and the heavy chain (hc) of brush border (BB) myosin I (110K-calmodulin complex) and rhodamine-conjugated phalloidin as a probe for F-actin, we determined that while actin, villin, and fimbrin were all localized apically along the entire axis, BB myosin I (hc) did not assume this localization until the crypt-villus transition zone. In addition to their localization at the BB surface, all four proteins were present at significant levels along the lateral margins of enterocytes along the entire crypt-villus axis, suggesting that these proteins may be involved in the organization and function of the basolateral membrane cytoskeleton as well. The pattern of expression of the microvillar core proteins along the crypt-villus axis in the adult was comparable to that seen in the intestine of the late stage chicken embryo and suggests that a common program for brush border assembly may be used in both modes of enterocyte differentiation.

Analysis of RNA transcripts for HLA class II genes in human small intestinal biopsies.

Studies of the expression of selected genes within the intestinal mucosa will provide important new information about physiologic pathological processes that effect mucosal growth, differentiation, and function. To study gene expression in the gut, we developed a method to obtain sufficient undegraded RNA from human endoscopic intestinal biopsy specimens for Northern and slot blot analysis. To verify the method, we examined the differential expression of HLA class II genes in small intestinal mucosa. Levels of RNA transcripts for HLA-DR, -DP, and -DQ alpha and beta chains were assessed in freshly isolated endoscopic intestinal mucosal biopsy specimens and compared with levels in Epstein-Barr virus transformed B cells from the same individuals. Sufficient undegraded cellular RNA with distinct 28S and 18S ribosomal bands could be obtained from as few as two 2-3 mm endoscopic biopsies. Using chain and locus specific cDNA probes, HLA-DR, -DP, and -DQ subregion genes were shown to be expressed in intestinal mucosa, with the relative magnitude of RNA transcripts being DR greater than DP greater than DQ. The same hierarchy of expression was seen for EBV-transformed B cell lines. This method, in conjunction with the polymerase chain reaction for amplifying specific RNA transcripts and in situ hybridisation methods for the cellular localisation of RNA transcripts, will enable studies on the regulation of gene expression in the intestinal mucosa.

Immunopathology of graft-versus-host disease in the upper gastrointestinal tract.

Class I and class II (HLA-DR, DP and DQ) MHC antigen expression and the phenotypic nature of the inflammatory infiltrate in gastric and duodenal biopsies in bone marrow transplantation patients with and without graft-versus-host disease were investigated. Increased expression of class I (P less than 0.016) and class II (HLA-DR, DP) antigens (P less than 0.002) was associated with GVHD. The epithelium in two GVHD-positive biopsies was HLA-DP-positive and HLA-DR-negative. None of the tissues expressed HLA-DQ. Association between MHC antigen expression and phenotype of infiltrating cell was then examined. The majority of GVHD biopsies showed an infiltrate composed of CD4+ cells and CD8+ cells. However, the two DP+, DR- biopsies were associated exclusively with CD8+ intraepithelial cells, suggesting sequential events in GVHD, with CD8+ cells infiltrating tissue first associated with HLA-DP expressions, followed by accumulation of CD4+ as well as CD8+ cells in association with expression of HLA-DR.

EGF- and TGF-alpha-like peptides in human fetal gut.

The presence of epidermal growth factor (EGF) and transforming growth factor-alpha (TGF alpha) immunoreactivities in fetal human tissues was studied immunohistochemically at different gestational ages. EGF and TGF alpha immunoreactivities were detected from the 20th gestational wk. EGF immunoreactivity was limited to the small intestine, but TGF alpha immunoreactive cells were present in the colon also. According to radioreceptor assay, the intestine of a 19-wk-old human fetus contained 10 times more EGF receptor-binding substance than EGF, as measured by immunofluorometric assay. Chromatographic analysis suggests that TGF alpha-like peptides account for at least part of this activity, as so argues in favor of the presence of TGF alpha- and EGF-like peptides in the human fetal gut. Whether they are synthesized in the fetus is yet unknown.

Influence of duodenal digesta composition on abomasal outflow, motility and small intestinal transit time in sheep.

1. A study was made of the influence of duodenal infusion of some of the components of the digesta on gastrointestinal motility, abomasal outflow and small intestinal transit time in seven sheep fed 1500 g grass pellets/day. Gastrointestinal motility was recorded by electromyography. Abomasal outflow was estimated according to the rate of dilution of CrEDTA injected and sampled via an abomasal catheter. Small intestinal transit time was measured by the passage of Phenol Red from the duodenum to the terminal ileum. 2. Abomasal outflow was inhibited during 3 h infusions (5 ml/min) of 100 mM-acetic, propionic, butyric and lactic acids, of 50 mM-HCl, of 0.56 M-glucose, and of 2 and 4% protein hydrolysate. Abomasal motility was inhibited by these infusions and by infusion of 234 mM-oleic acid (0.75 ml/min), of a fat emulsion (Intralipid 20% 0.3 ml/min) and of 50 mM-L-tryptophan (7.5 ml/min). 3. Abomasal motility and, where tested, abomasal outflow, were not affected by duodenal infusion of 150 mM-NaHCO3 (5-10 ml/min), 0.28 M-NaC1 (5-7.5 ml/min), distilled water (5-7.5 ml/min), 25 mM-L-tyrosine (5 ml/min), and of 50 mM-acetic, propionic, butyric and lactic acids (5 ml/min). 4. At concentrations or rates of infusion above the threshold dose needed to inhibit abomasal motility, small intestinal motility was altered and the frequency and amplitude of the reticulo-ruminal contractions were inhibited. 5. The transit time through the small intestine was increased during infusion of 100 mM-acetic, propionic, butyric and lactic acids and decreased during infusion of 0.56 M-glucose and Intralipid. 6. Inhibition of abomasal motility and outflow in sheep receiving 1500 g/day grass pellets was calculated to require increases in the duodenal concentration of volatile fatty acids of about 150% and K+ of about 38%, and to require an increase in the rate of delivery to the duodenum of H+ of about 90%, nitrogen of about 22% glucose of about 2000% and fat of about 84%. 7. These findings are discussed in relation to the composition of abomasal and duodenal digesta in sheep fed different diets. 8. It seems likely that components of duodenal chyme, such as H+, volatile fatty acids, glucose and fat only affect abomasal outflow in sheep fed high-grain diets (glucose, volatile fatty acids), or diets highly supplemented with fat (fat), for short periods after meal feeding (volatile fatty acids) or under abnormal conditions (H+).(ABSTRACT TRUNCATED AT 400 WORDS)

Increased tissue concentration of neuropeptide Y in the duodenal mucosa in coeliac disease.

Neuropeptide Y (NPY) is localized to intestinal nerve fibres, of which there are few in normal duodenal mucosa. In the duodenal mucosa of 10 patients with coeliac disease and in a control group of 21 patients with other gastrointestinal symptoms but with normal function of the small intestine we studied the frequency of such fibres by immunohistochemistry and the tissue concentration of NPY by radioimmunoassay. Patients with coeliac disease had an increased number of NPY nerve fibres and significantly elevated tissue concentrations compared with the control group. The eluted fractions obtained by high-pressure liquid chromatography of duodenal extracts showed the same immunoreactive components in the two groups. This study therefore suggested proliferation of the peptide-containing nerve system in coeliac disease. The increased NPY levels in the duodenal mucosa may be of functional significance for the disease symptoms.