Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: HUMANGGP:036187 (gut)
 73,132 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The aim of this work was to investigate why non-lactating dairy cows are less susceptible to the development of ketonaemia during food deprivation than are dairy cows in early lactation. 2. The first experiment (Expt. A) consisted of determining the effect of 6 days of food deprivation on the concentrations of ketone bodies, and of metabolites related to the regulation of ketogenesis, in jugular blood and liver of non-lactating cows. 3. During the food deprivation, blood ketone-body concentrations rose significantly, but to a value that was only 16% of that achieved in lactating cows deprived of food for 6 days [Baird, Heitzman & Hibbitt (1972) Biochem. J. 128, 1311--1318]. 4. In the liver, food deprivation caused: a rise in ketone-body concentrations; a fall in the concentration of glycogen and of various intermediates of the Embden-Meyerhof pathway and the tricarboxylic acid cycle; an increase in cytoplasmic reduction; a decrease in the [total NAD+]/[total NADH] ratio; a decrease in energy charge. These changes were all qualitatively similar to those previously observed in the livers of the food-deprived lactating cows. 5. There appeared therefore to be a discrepancy in the food-deprived non-lactating cows between the absence of marked ketonaemia and the occurrence of metabolic changes within the liver suggesting increased hepatic ketogenesis. This discrepancy was partially resolved in Expt. B by the observation in two catheterized non-lactating cows that, although there was a 2-fold increase in hepatic ketogenesis during 6 days of food deprivation, ketogenesis from the splanchnic bed as a whole (i.e. gut and liver combined) declined slightly owing to cessation of gut ketogenesis.
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PMID:Effects of food deprivation on ketonaemia, ketogenesis and hepatic intermediary metabolism in the non-lactating dairy cow. 21 50

The enteric nerve plexuses of the domestic fowl (Gallus domesticus) were investigated in sections and stretch preparations by means of the cholinesterase and glyoxylic acid fluorescence histochemical techniques. Cholinesterase-positive and varicose and non-varicose fluorescent nerve fibers were distributed at all levels of the gut in myenteric, submucosal, muscle and mucosal plexuses, and in a perivascular plexus. The density of the innervation and the detailed distribution of the nerves varied in different parts of the intestinal tract. All nerve plexuses appeared to be best developed in the rectum. Whereas the circular muscle coat contained a substantial number of nerves at all levels of the gut, the longitudinal coat was well innervated only in the rectum. The major portion of the mucosal plexus appeared to be associated with the intestinal glands. The nerve cell bodies were restricted to the myenteric and submucosal plexuses and were mainly cholinesterase-positive. Fluorescent ganglion cells were not observed. Pretreatment of stretch preparations with NADH: Nitro BT to stain ganglion cells showed that the majority of the cells were surrounded by a meshwork of fluorescent varicose fibres, although none of the fibres appeared to be associated with individual cells. The perivascular plexus was mainly associated with the arteries. The functional significance of the innervation is discussed.
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PMID:Avian enteric nerve plexuses. A histochemical study. 65 58

The authors examined peroperatively 41 excisions from the muscularis externa of the large bowel in 20 patients operated on account of intestinal dysganglionosis. For visualization of the ganglion cells the reaction for NADH tetrazolium reductase was used. The advantage of this method is that the incubation medium can be very rapidly prepared from a stock solution and that the incubation period is short. The visualization of ganglion cells is by contrast. In all instances it was possible to assess the length of the aganglionic and markedly hypoganglionic portion of the gut and make thus the result of the operation safer.
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PMID:[Personal experience with the use of peroperative biopsy in surgery for intestinal aganglionosis]. 152 14

Intestinal epithelial cells are capable of metabolizing a wide variety of exogenous substrates. To determine how this metabolic capacity may affect endogenous substances such as steroid hormones, we examined the ability of rat gut epithelial preparations to hydroxylate estradiol at the C-2 position. Utilizing a site-specific tritium exchange assay, an active estrogen 2-hydroxylase system was shown to be localized to gut mitochondria throughout the intestine, with enzymatic activities comparable to the activity in crude hepatic homogenates of non-induced animals (0.2 nmol/min/mg protein). Gas chromatography-mass spectrometry confirmed the formation of C-2 hydroxylated estrogens by these mitochondrial preparations. The enzyme system was shown to involve a saturable monooxygenase, utilizing NADH (preferably) or NADPH in a protein- and time-dependent fashion. The Michaelis-Menten constant for this pathway was approximately 150 microM. Enzyme activity decreased by 20% in the presence of carbon monoxide, and was largely unaffected by organic P450 inhibitors such as alpha-naphthoflavone, metyrapone, and SKF-525A. These studies suggest that intestinal mitochondria are able to contribute to the oxidative metabolism of endogenous estrogens circulating within the enterohepatic pool.
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PMID:Oxidative metabolism of estrogens in rat intestinal mitochondria. 157 77

A simple three-step colorimetric assay based on the tetrazolium salt MTT (3-(4,5 dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) has been developed for quantifying filarial viability. Living (but not dead) filariae take up MTT and rapidly reduce it to formazan, so staining themselves dark blue. This colour change which is easily seen provides a rapid qualitative test for filarial viability. Quantitative data can be obtained by solubilizing formazan out of the worm with DMSO and measuring the absorbance of the resulting solution at 510 nm. To date the technique has been demonstrated in several species of filariae including Onchocerca volvulus. MTT reduction is thought to be selective for NADH-dependent dehydrogenase activity in viable worms. The reaction occurs readily in all developmental stages of Dipetalonema viteae including fragments of filarial tissue. Enzyme activity in viable intact D. viteae appears to be primarily associated with the hypodermis/muscle cells, with minimal formazan formation in the gut and reproductive tracts. The application of this MTT assay as a parameter for quantifying in vitro drugs effects is described. Assay procedures have been developed and optimized with D. viteae and Brugia pahangi for the assessment of effects of macrofilariae and microfilarial release, and the activity of a range of antifilarial standards reported. Several potential applications of the technique to studies on filarial biology are discussed.
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PMID:Colorimetric quantitation of filarial viability. 270 65

Cellular retinol-binding protein, type II (CRBP (II], an abundant protein of the rat small intestine, has recently been shown to be able to bind retinaldehyde in addition to retinol (MacDonald, P.N., and Ong, D. E. (1987) J. Biol. Chem. 262, 10550-10556). Retinaldehyde is produced in the intestine by oxidative cleavage of beta-carotene. The next step in the intestinal metabolism of vitamin A is the reduction of retinaldehyde to retinol which is then esterified for incorporation into chylomicrons. In the present study retinaldehyde bound to CRBP(II) was found to be available for reduction by microsomal preparations from rat small intestinal mucosa. The microsomal activity was about 8 times greater than the activity observed for an equal amount of cytosolic protein. Retinaldehyde reduction utilized either NADH or NADPH as cofactor, with NADH being slightly more effective. The apparent Km for retinaldehyde-CRBP(II) was 0.5 microM, and the Vmax was approximately 300 pmol/min/mg protein, a rate more than sufficient for the needs of the animal. The product retinol remained complexed to CRBP(II). The microsomal enzyme activity reduced free and bound retinaldehyde to approximately the same extent, although the aldehyde function of retinaldehyde bound to CRBP(II) was less accessible to chemical reducing agents than that of free retinaldehyde. Retinol bound to CRBP(II) could not be oxidized by the microsomal activity in the presence of NAD+, while free retinol or retinol bound to bovine serum albumin was oxidized to retinaldehyde. The more favorable reduction versus oxidation of retinoid bound to CRBP(II) consequently favored the reaction known to be required for the ultimate conversion of beta-carotene to retinyl esters for export from the gut.
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PMID:Reduction of retinaldehyde bound to cellular retinol-binding protein (type II) by microsomes from rat small intestine. 341 42

A histological and histochemical study of ingested food material, energy stores and enzymes in the monogenean Pseudodactylogyrus anguillae, parasitizing the gills of the European eel (Anguilla anguilla) is presented. It was found that mucus, epithelial cells and blood from the gills were ingested. Glycogen deposits were small and primarily located in the parenchyma and to a minor extent in the vitellariae. Numerous globules of neutral lipids were found in the vitellariae. A marked esterase activity was found in the gut and a less marked activity in the vitellariae. Acid phosphatase activity was found throughout the body whereas alkaline phosphatase and leucine-amino-peptidase were not detected. Marked activity of succinate dehydrogenase and NADH-diaphorase was found in all cells, indicating a predominantly aerobic metabolism in this monogenean.
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PMID:The nutrition of the gill parasitic monogenean Pseudodactylogyrus anguillae. 342 77

1. Soluble and mitochondrial forms of histidine-pyruvate aminotransferase were separated from rat liver preparations by chromatography on DEAE-cellulose. 2. These enzymes were characterized with respect to substrate specificity, substrate affinity, pH optimum, stability and molecular weight by chromatography on Sephadex G-200. 3. Each enzyme has a relatively broad specificity showing significant activity towards l-phenylalanine and l-tyrosine and catalysing transamination with a number of monocarboxylic 2-oxo acids. 2-Oxoglutarate is not a substrate for either enzyme. 4. The molecular weights of the two enzymes, by chromatography on Sephadex G-200, are in the range 130000-150000. 5. The formation in vitro of imidazolyl-lactate from imidazolylpyruvate and NADH was demonstrated by using liver preparations. 6. From a study of imidazolyl-lactate-NAD(+) oxidoreductase activity after electrophoresis of liver preparations on polyacrylamide gel, and from an examination of the activity of l-lactate-NAD(+) oxidoreductase (EC 1.1.1.27) towards imidazolylpyruvate, it is concluded that this latter enzyme is responsible for the formation of imidazolyl-lactate in the liver. 7. Preparations of bacteria obtained from rat faeces form imidazolylpropionate from l-histidine and urocanate without further subculture. The amount of imidazolylpropionate formed is increased under anaerobic conditions and more so in an atmosphere of H(2). It is suggested that the gut flora of the rat contribute largely, if not exclusively, to the formation of imidazolylpropionate normally found in the urine.
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PMID:The degradation of L-histidine in the rat. The formation of imidazolylpyruvate, imidazolyl-lactate and imidazolylpropionate. 436 Jul 16

A potent inhibitor of microsomal mixed-function oxidation reactions in insects had previously been isolated and partially purified from the gut contents of Prodenia eridania and shown to be associated with proteinase activity. Incubation of rat liver microsomal fraction with low concentrations of this inhibitor led to solubilization of NADPH-cytochrome c reductase, which was paralleled by the inactivation of reduction of cytochrome P-450 by NADPH and by the inhibition of NADPH-linked benzo[3,4]pyrene hydroxylation and aminopyrine demethylation. There was little or no effect on cytochromes b(5) and P-450, nor was the capacity of the latter catalyst to combine with exogenous substrates decreased. Contrary to the findings with NADPH, preincubation of microsomal fraction with the inhibitor did not cause a significant decrease in the rate of cytochrome P-450 reduction by NADH, supporting the assumption that different catalysts are involved in the electron transfer from NADH and NADPH to cytochrome P-450. The findings indicate the importance of taking the possible presence of endogenous inhibitors into consideration when evaluating low or absent mixed-function oxidation activities found in insect systems in vitro.
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PMID:Mechanism of inhibition of microsomal mixed-function oxidation by the gut-contents inhibitor of the southern armyworm (Prodenia eridania). 440 Jun 5

The metabolism of [U-(14)C]phenylmercury acetate was studied in the rat. After a single subcutaneous dose a small proportion is excreted unchanged in urine, and a larger amount in bile with some resorption from the gut. The greater part of the dose is broken down in the tissues to yield inorganic mercury which is excreted mainly in faeces, and conjugates of phenol and quinol are excreted in urine. In experiments in vitro phenylmercury is broken down by liver homogenates to release inorganic mercury and benzene; this reaction is effected by the soluble, but not the microsomal, fraction and does not require NADPH or NADH. No elemental mercury is formed under these conditions. It is probable that this reaction occurs in vivo and the benzene produced is rapidly converted into phenol and quinol by microsomal enzymes.
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PMID:The metabolism of phenylmercury by the rat. 465 29


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