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D Pansu

Publications and source records attributed to D Pansu.

10 recordsLinked to original sources
PubMed1992

Effect of sorbin on duodenal absorption of water and electrolytes in the rat.

Sorbin is a newly isolated intestinal peptide that has been purified because of its ability to induce water absorption. The effects that sorbin and some synthetic peptides corresponding to its C-terminal sequence have on duodenal absorption of water, chloride, and sodium were studied in comparison with the effects of vasoactive intestinal peptide (VIP), [D-Ala,Met]-enkephalinamide (DAMA), and angiotensin II. The technique of an in situ ligated duodenal loop in the rat was used for all peptides. Under the experimental conditions used, a low basal secretion of water, chloride, and sodium was obtained; VIP induced an increase of the secretion, whereas DAMA induced an absorption, both in the nanomolar dose range. Angiotensin II and sorbin induced an absorption in the picomolar dose range. The most effective doses of sorbin peptides but not of angiotensin induced the lowest final concentrations of Na+ and Cl- obtainable without inducing secondary water secretion. All synthetic peptides containing the C-terminal heptapeptide of sorbin were active in the picomolar dose range. Contrary to angiotensin, they had no effect on blood pressure.

Amino Acid Sequence↗
PubMed1992

Comparison of VIP-induced electrolyte secretion at three levels in rat small intestine.

Duodenal, jejunal and ileal loops were prepared and an iso-osmotic test solution injected, containing 80 mM Na+, 5-mM K+, 1.2 mM Ca2+, 77 mM Cl-, 10 mM HCO3- and 136 mM mannitol. 14CPEG 4000 was used as a non-absorbable marker and 36Cl was added to measure the bidirectional fluxes. During the 60-min in vivo incubation time, the duodenum actively secreted bicarbonate, a virtually zero flux in the jejunum was observed, whereas the ileum absorbed water and chloride and secreted bicarbonate. The response to the perfused doses of 0.15 to 2.4 nmol.100 g-1.h-1 of VIP (vasoactive intestinal peptide) differed qualitatively and quantitatively in the 3 segments: VIP increased bicarbonate secretion and induced chloride secretion in the duodenum, induced chloride secretion in the jejunum without changing bicarbonate minimal influx, induced bicarbonate secretion and suppressed chloride absorption in the ileum. The minimal dose required was lower in the duodenum (0.3 nmol.100 g-1.h-1) than in the jejunum and ileum (1.2 nmol.100 g-1.h-1). The functional heterogeneity of the small intestine was clearly demonstrated after VIP stimulation.

Animals↗
PubMed1991

Isolation and characterisation of porcine sorbin.

Sorbin has been isolated from extracts of porcine upper intestine, and the biological activity in absorbing water and electrolytes utilized to monitor the purification procedure. Pure sorbin was obtained in a yield of about 1 mg/Mg boiled intestine. The protein chain has 153 amino acid residues and the primary structure was determined by analyses of CNBr-cleaved fragments and four enzymatic digests. The protein has a free N-terminal Met and an amidated C-terminal Ala. No structural similarity was observed with other known proteins in data bases, but several segments have special properties and the C-terminal half is rich in Pro and Arg.

Absorption↗
PubMed1990

Effect of D ala2 metenkephalinamide on feline jejunal and ileal water and electrolyte transport.

The aim of this investigation was to compare the effect of an opioid, D ala2 metenkephalinamide (DAMA), on net jejunal and ileal water and electrolyte fluxes using the gut perfusion technique in the anesthetized cat. Intestinal transport was measured during intravenous infusion of serial doses of 2, 6, and 18 micrograms.kg-1.h-1 of DAMA in 6 cats. Each cat was its own control during an intravenous infusion of 150 mmol/l NaCl preceding the first dose of peptide and following the last dose of DAMA. Both jejunal and ileal segments were isolated by inflated balloons and were studied at the same time. Fifteen ml of an iso-osmolar test solution with hypo-osmolar ion contents and complementary mannitol were administered in the upstream tube and collected 1 h later in the downstream tube. In the jejunum, water secretion was dose-dependently reversed to an absorption from a control value of +0.5 +/- 0.4 to -0.83 +/- 0.5 ml.h-1.10 cm-1; in the ileum, water absorption was increased from -0.5 +/- 0.3 to -1.5 +/- 0.2 ml.h-1.10 cm-1. The net absorption of all electrolytes, ie sodium, chloride, bicarbonate, potassium and calcium also increased during peptide administration. However, a qualitative difference in the ion transport was observed between the jejunum and the ileum.

Animals↗
PubMed1979

Effect of lactose on duodenal calcium-binding protein and calcium absorption.

Rats were fed a purified diet containing 30% lactose and calcium absorption was measured in duodenal loops in situ following instillation of 1.25 or 10 mM CaCl2 solutions. Lactose feeding caused absorption to be depressed from 88 to 69% (1.25 mM Ca solution) and from 71 to 43% (10 mM Ca solution). The effect of lactose feeding was more pronounced in 5-month old rats than in 2-month old rats. In the lactose-fed rats, calcium-binding protein (CaBP), measured by a competitive binding assay following partial purification, was depressed on the average from 24 to 10 nmoles Ca bound per mg protein. The effect of the lactose ingestion can be likened to the effect expected from continued high calcium intake, i.e., a decrease in the efficiency of calcium absorption and a decrease in CaBP.

Aging↗
PubMed1977

[Regulation of cell renewal in the gastrointestinal mucosa (author's transl)].

The renewal of the digestive mucosa is the most efficient process assuming the maintenance of the gastrointestinal barrier. The mucous and absorptive cells, born in the proliferative zone, are migrating to the surface and they extrude duirng meals, living 4 to 6 days. Hyperphagia, pregnancy, lactation and intestinal resection induce a hypertrophic state. Fasting, ageing, germ free status provoke a hypoplasia. The ulcerogenic and antimitotic drugs decrease the proliferative activity. The gastrointestinal cell renewal is controlled by hormonal, vitaminic and nervous agents. Gastrin and growth hormone are the major trophic factors, secretom amd cprtocpsteroids act as antitrophic agents. The vitamins A, D and B12, and the nervous transmittors participate in the feed back control assuming a steady state between proliferation and extrusion. Chalones and immunologic factors are probably the most important but unknown inhibitors. The pathological events concerned with abnormal renewal are peptic ulcer, atrophic gastritis, intestinal villous atrophy and digestive cancer.

Animals↗