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Query: HUMANGGP:036187 (gut)
 73,132 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cardiac output and regional blood flows to myocardium, gut, uterus and kidney were determined in anaesthetised female rats by a single injection of 86RbCl. The haemodynamic responses were measured at various time intervals up to 2 h after single I.V. injections of lysine-vasopressin and the following of its analogues: a) with extended peptide chains at the N-terminal (including "hormonogens") Nalpha-glycyl-glycyl-lysine-vasopressin, Nalpha-glycyl-glycyl-glycyl-arginine-vasopressin and Nalpha-D-valyl-lysine-vasopressin, b) "carba" modifications desamino-carba6-arginine-vasopressin, desamino-carba6-D-arginine8-vasopressin, desamino-carba6-ornithine8-vasopressin, desamino-dicarba-arginine-vasopressin and c) other steric alterations - desamino-D-arginine8-vasopressin and desamino-N-methylarginine8-vasopressin. Sub-pressor doses of lysine-vasopressin were followed by marked reductions in gut and uterus blood flows which reached a peak at 10 min. and had completely receded by 60 min. The presence of steric alterations in the C-terminal tripeptide of the molecule- D-arginine or N-methylarginine in sequence position 8 - practically completely eliminated vascular activity. The same was true for Nalpha-D-valyl-lysine-vasopressin. None of the latter three analogues showed any inhibitor properties to the action of lysine-vasopressin. The two hormonogens (triglycyl N-terminal extensions) had to be given in doses 10 times greater to obtain a vasoconstrictor effect in gut and uterus equivalent in amplitude to that of a lysine-vasopressin, but this effect was still present to the same degree 2 h later with the hormonogen of lysine-vasopressin, and was only starting to return to baseline values at the same time with the arginine-vasopressin hormonogen. The vascular potency of both mono-carba L-analogues was higher than that of lysine-vasopressin, and the effect was as prolonged as with the hormonogens. The dicarba analogue also showed a prolonged action, but with much reduced potency. No significant changes in renal or myocardial blood flows were observed at all. Molecular features of vasopressin smooth muscle activity were discussed, and a receptor model was proposed. It was suggested that the -S-S-, -CH2CH2-bridges in the above analogues are not directly bound in the peptide-receptor complex and constitute the limiting factor determining complex duration, or persistence of the active peptide in the "receptor compartment". These results provide an experimental basis for possible clinical application of triglycyl-vasopressin and carba-vasopressin in bleeding from both gut and uterus and for induction of menstruation.
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PMID:Regional and systemic haemodynamic effects of some vasopressins: structural features of the hormone which prolong activity. 16 85

1. A slope-ratio assay was developed with growing pigs to determine the availability of lysine in five protein concentrates. The basal diet contained 5.2 g lysine/kg and six levels of lysine, in 500 mg/kg increments, were used to determine the pig's response to standard lysine. The protein concentrates were incorporated into the basal diet to provide five levels of total lysine, again in 500 mg/kg increments, at the expense of wheat starch. A daily feeding scale based on live weight was used to ensure similar nutrient intakes. Pigs were fed at three-hourly intervals to ensure the utilization of free amino acids in the diets. Four pigs were allotted to each dose level and response was assessed over the 20--45 kg growth phase. 2. Potency estimates for available lysine in the five protein concentrates varied, depending on whether live-weight gain or carcass gain was used as the criterion of response. Carcass gain was considered more appropriate as it was not influenced by variation in gut fill. Availability of lysine in the five proteins, using carcass gain/d were (proportion of total) cottonseed meal 0.39,fish meal 0.89, meat-and-bone meal 0.50, skim-milk powder 0.88 and soya-bean meal 0.87. 3. Rat slope-ratio assay results for available lysine in the five protein concentrates were in general agreement with those from the pigs. In contrast, the differences in available lysine were not detected by the chemical Silcock available-lysine test (Roach et al. 1967) nor by the direct fluorodinitrobenzene procedure (Carpenter, 1960).
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PMID:Availability of lysine in protein concentrates as determined by the slope-ratio assay with growing pigs and rats and by chemical techniques. 42 90

Transport of lysine across the rat jejunum has been studied measuring transmural fluxes, Jms and Jsm, under short-circuit conditions, influx across the brush-border membrane, Jmc, under open-circuit and voltage-clamp conditions, and steady-state uptake by the isolated mucosa. 1. Jlysmc can be described as the sum of a saturable process with a Kt of 3 mM and a Jmax of 2.25 micromole/cm2.hr and a diffusional component corresponding to a lysine permeability of 0.014 cm/hr. Also Jlysms is well described as the sum of a saturable process and a diffusional contribution described by the same permeability as for Jlysmc. 2. The effects of the transmural p.d. on Jlysmc indicate that at 60 mM this flux includes a diffusional contribution, which corresponds to a lysine permeability of 0.014 cm/hr. 3. The passage of an electrical current across the gut wall changes the electrical conductance as expected for a cation-selective epithelium. The effect of a mucosa to serosa current on the Jms value of mannitol provides confirmation of the expected current effect on transepithelial volume flow. These effects on conductance and solute flux, together with the electrostatic effect on lysine movements, suffice to account for the p.d. effects on Jmc, Jms, and Jsm of lysine. 4. Jlyssm is in a saturable manner stimulated by increasing concentrations of D-glucose. At higher (10 mM) concentrations of lysine this effect leads to a net secretion of lysine. Qualitatively and quantitatively these effects are consistent with the model of a glucose-induced fluid circuit between the mucosal solution and the lateral intercellular spaces. 5. All observations are consistent with a paracellular, transepithelial pathway for lysine, which includes the lateral intercellular spaces. 6. The transport of lysine across the basolateral membrane is analysed. Togethet the data on transcellular passage of lysine are very similar to those reported for rabbit ileum, except that more than one transport process could not be demonstrated.
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PMID:Lysine transport across rat jejunum: distribution between the transcellular and the paracellular routes. 48 Feb 16

Nalpha-triglycyl-(8-lysine)-vasopressin (TGLVP) was administered intravenously to pregnant guinea pigs and the effect on regional blood flow examined by the radioactive microsphere technique. A dose of 10 mug/kg TGLVP caused an elevation of the mean arterial blood pressure, from 6.4 to 11.1 kPa, a significant reduction in blood flow to the gut, skin and skeletal muscle and a significant increase in blood flow to the spleen. The number of 15 +/- 5 mum microspheres reaching the lungs diminished significantly after 10 mug/kg TGLVP, indicating that this dose constricted arterio-venous short circuits in the systemic circulation. There was also a decrease in blood flow to the urogenital tract, including the placentae. When 3 mug/kg TGLVP was injected, the mean arterial blood pressure rose from 6.5 to 8.7 kPa and there was no longer any consistent effect on maternal placental blood flow. It is suggested that pregnancy constitutes a contraindication for TGLVP, since a reduction in uterine and maternal placental blood flow might occur with clinically relevant doses.
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PMID:Effect of a vasopressin analogue (Nalpha-glycyl-glycyl-glycyl-[8-lysine]-vasopressin) on organ blood flow in the pregnant guinea pig. 57 64

The plasma concentrations of substrates, together with transhepatic and transgut balances, have been studied in six control and eight septic awake fasted dogs. Four severely ill septic dogs (typically fluid in chest and/or abdomen, extensive peritonitis, respiratory difficulties) had high concentrations of threonine, glycine, tyrosine, lysine, histidine, tryptophan, and triglycerides (p less than or equal to 0.05). The other septic dogs (less severely ill) showed fewer and less pronounced alterations in the plasma substrates (aspartate and tryptophan were elevated, p less than or equal to 0.05). The infusion of glucose increased the concentration of glucose, lactate, and pyruvate and depressed the concentrations of most amino acids in both normal and septic dogs. Threonine, asparagine, glutamine, leucine, isoleucine, alpha-aminobutyrate, and tyrosine were significantly depressed in the severely ill septic dogs (p less than or equal to 0.05). In the normal dogs most amino acids were removed by the liver, with alanine accounting for approximately 40% of the total. Glutamine removal was negligible. In the septic dogs hepatic removal of amino acids was variable; livers of two severely ill septic dogs did not remove amino acids. In the control dogs glucose infusion (0.015--0.017 g/kg/min) tended to lower hepatic removal of amino acids. Hepatic dye removal in the septic dogs was always very poor. In the gut glutamine was removed and alanine, glutamate, glycine, and ammonia produced, but the overall sum of amino acid uptake was negligible in both the control and septic dogs. The ratio of tryptophan to the sum of valine, isoleucine, leucine, tyrosine, and phenylalanine concentrations was greatly elevated in all septic dogs in which it was measured. The free concentrations of amino acids in the liver, heart, and muscle tissues were grossly elevated in the low intravenous alimented septic state relative to the fasted normal state, whereas the tissue concentrative ability as measured by nonmetabolizable amino acids, alpha-aminoisobutyrate and cycloleucine, was not similarly increased. Sepsis clearly alters plasma and tissue concentrations, and in some instances hepatic uptake of amino acids.
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PMID:Plasma concentrations and tissue uptake of free amino acids in dogs in sepsis and starvation: effects of glucose infusion--some effects of low alimentation. 65 52

The animo acids in the deproteinized haemolymph of Glossina austeni females, before and after hydrolysis, have been determined at 12 different times during the 1st 2 pregnancy cycles. Hydrolysis resulted in a large increase in the concentrations of tyrosine, phenylalanine, aspartate and lysine, indicating that these amino acids are present mainly as peptides in the haemolymph. The rate of transfer of the aromatic amino acids to the offspring, based upon the amino acid content of the larval gut, must be exceptionally high and has been estimated to be at least 7.9 microgram/h.
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PMID:Changes in free amino acids and peptides in the haemolymph of Glossina austeni during the reproductive cycle. 72 Apr 71

A 3-year-old boy with hyperdibasicaminoaciduria and hyperammonemia showed characteristics of familial protein intolerance (FPI). Oral loading tests of lysine and arginine disclosed a remarkably reduced capability for intestinal absorption of these amino acids. Because urinary excretion and renal clearance of dibasic amino acids were only moderately elevated in the patient, the conspicuously decreased serum concentration of lysine, arginine, and ornithine was attributed to the defect in internal absorption. A possible explanation for elevated blood ammonia levels in FPI is that it is due to a deficiency of arginine and ornithine in the urea cycle that in turn results from a severe impairment in absorption of the amino acids by the gut mucosa.
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PMID:Hyperdibasicaminoaciduria and hyperammonemia in familial protein intolerance. 99 77

Ileal transport of dibasic amino acids has not previously been studied in the intestine of healthy volunteers or cystinuric patients. Experiments have therefore been designed to compare ileal and jejunal absorption of lysine and arginine both in normal subjects and cystinuric patients. In addition, jejunal perfusion experiments have been carried out to investigate absorption of the dipeptide L-arginyl-L-leucine. The results indicate that, at the concentrations studied (4.2 mM lysine, 1 mM arginine), severe transport defects exist throughout the whole small intestine for both amino acids in cystinuria. Despite the transport defect for free arginine, cystinuric patients absorbed the dipeptide L-arginyl-L-leucine normally. Because of the transport defect for free arginine, it has been possible to show that during absorption of L-arginyl-L-leucine in cystinuria approximately 30% of dipeptide-bound arginine can be recovered from the gut lumen in the free form. These findings indicate that the prime function of specific amino acid transport systems during the absorption of protein digestion products may be as a "recapture mechanism" for amino acids liberated as a result of mucosal cell peptide hydrolysis.
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PMID:Jejunal and ileal absorption of dibasic amino acids and an arginine-containing dipeptide in cystinuria. 113 25

The study of six trypsins (crayfish, dogfish, horse, pig, sheep, bovine) showed that among these the highest lysine + arginine content and the highest inactivation rate occur in specialized herbivorous animals with extreme length of gut. Since the autocatalytic degradation in trypsins can take place only at lysine or arginine residues, an accumulation of basic amino acids, the increase of the autocatalytic inactivation rate and the relative length of gut might be correlated during the evolution of mammalian trypsins.
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PMID:[Accumulation of basic amino acid residues, rate of autolysis and relative length of gut during trypsin evolution (author's transl)]. 119 40

The antidiuretic action of a number of vasopressin analogues has been measured in the rat and man in water diuresis. These analogues had the following categories of structural alteration: a) substitution of -CH2CH2-(dicarba) and -SCH2-(6-monocarba) for the natural -SS- bridge between residues 1 and 6, b) changes in the nature of the C-terminal tripeptide produced by substitution of D-arginine and L-Nalpha-methylarginine for L-arginine in sequence position 8 and L-leucine for proline in position 7, and c) combinations of a and b. In addition, a highly active analogue which results when valine is substituted for glutamine in position 4 was tested. Trained, unanesthetized rats and normal human volunteers were complemented by a volunteer patient with posttraumatic diabetes insipidus (DI) in the total group of experimental subjects. The only change in the C-terminal tripeptide which was associated with a high antidiuretic action was D-Arg substitution. The meArg and Leu analogues showed low to very little activity and no signs of antidiuretic antagonist action. All of the carba analogues showed both high potency and prolongation of antidiuretic action in the following order (for both potency and duration): monocarba + 8-D-Arg greater than 4-Val + 8-D-Arg greater than 8-D-Arg alone, all in deamino form. None of the 8-D-Arg analogues had any side effects on the cardiovascular system, gut, uterus, bladder, etc. The prolongation was such that even with a DI patient refractory to the action of lysine-vasopressin and relatively resistant to deamino-[8-D-Arg]-vasopressin, water turnover could be reduced from untreated levels of 20 to 30 liters/day to less than 2 liters/day with only a single administration of deamino-6-carba-[8-D-Arg]-vasopressin as nose drops. The significance of these structural alterations in the vasopressin molecule for interaction with both antidiuretic and smooth muscle receptors was discussed.
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PMID:Role of the disulfide bridge and the C-terminal tripeptide in the antidiuretic action of vasopressin in man and the rat. 119 61


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