Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.3.1 (alkaline phosphatase)
47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The cellular localization of preprosomatostatin mRNA in the rat brain and sensory ganglia has been examined in detail using a newly developed highly sensitive non-radioactive in situ hybridization histochemistry procedure. An alkaline phosphatase labelled anti-sense 30mer oligodeoxynucleotide probe was used for detection of somatostatin mRNA. This probe readily demonstrated somatostatin gene expression throughout the rat CNS with very high contrast and good cellular localization. As a result, we visualized numerous somatostatin mRNA-positive cells in many CNS areas which had previously not been shown to contain a mRNA signal. This method detected a number of somatostatin mRNA-positive cells, in the mitral cell layer of accessory olfactory bulb, the glomerular layer of the main olfactory bulb, the dorsal part of the lateral septum, superficial gray layer of superior colliculus, inferior colliculus, anterior ventral cochlear nucleus, granular layer and Purkinje cell layer of cerebellum, and substantia gelatinosa of medulla and spinal cord, all areas where signal detection using radiolabelled in situ probes has previously been rather difficult. The principle advantages of the present method include the very precise cellular resolution of signal, the rapid reaction time and low background. The sensitivity of the present method seems to be at least equivalent to most immunocytochemical procedures and more sensitive than most isotopic in situ hybridization methods.
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PMID:Distribution of somatostatin mRNA in the rat nervous system as visualized by a novel non-radioactive in situ hybridization histochemistry procedure. 197 30

The influence of somatostatin injection on intestinal disaccharidase and alkaline phosphatase activity in rat and chick was investigated. Disaccharidase and alkaline phosphatase activities of rat and chick homogenates were not modified. In rat the activities of mucosal brush-border maltase and sucrase were significantly increased. In chick brush-border a significant increase of duodenal mucosal activity and duodenal and jejunal sucrase activity is observed.
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PMID:Effect of somatostatin on small intestine enzyme activities in rat and chick. 285 90

Fractions of isolated epithelial cells were harvested from a segment of porcine jejunum by ten successive incubations with a chelating buffer. The cell fractions showed a progressive decrease in the activity of the brush-border enzymes, alkaline phosphatase and sucrase, with increasing incubation number but a progressive increase in the ability to incorporate labelled thymidine into DNA. Fractions enriched in cells from the crypt region (fractions 9 and 10) contained higher concentrations per mg protein of somatostatin-like immunoreactivity (1.8-fold), glucagon-like immunoreactivity (5.3-fold) and serotonin (3.0-fold) than fractions enriched in cells from the villus tip (fractions 1 and 2). Analysis of extracts of the fractions by gel filtration/radioimmunoassay showed that somatostatin-28 represented the predominant molecular form of somatostatin-like immunoreactivity in all cell fractions but the relative proportion of somatostatin-14 (and related metabolites) to somatostatin-28 was significantly higher (P less than 0.05) in fractions enriched in villus cells (fraction 1 and 2) than in fractions enriched in crypt cells (fractions 5-10). This result suggests that metabolism of somatostatin-28 to somatostatin-14 takes place during migration of the D cell from the crypt base to the villus tip. Heterogeneity in the somatostatin-14 region of the chromatograms indicates that the peptide may be further metabolized by the action of aminopeptidases.
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PMID:Conversion of somatostatin-28 to somatostatin-14 during maturation of epithelial cells in the porcine jejunum. 286 59

We have developed a model for combined morphological and functional in vitro studies of the isolated mediobasal hypothalamus (MBH) by considering two prerequisites: (1) the tissue must be well preserved, free of morphological artefacts and functionally unimpaired until the end of the in vitro incubation, and (2) the tissue must be processed for morphology in optimal conditions. To test our model we have studied some aspects of the luteinizing hormone-releasing hormone (LHRH) system in 4-month-old male Sprague-Dawley rats. After decapitation the MBH was isolated and put in a flask containing 0.5 ml Hepes-buffered Locke's medium gassed by 5 ml/min of O2/CO2 (95%/5%) and shaken in a water bath at 37 degrees C. After a 10-min washing, the medium was changed twice at an interval of 20 min. After the in vitro incubation the tissue was satisfactorily preserved as judged by light- and electron-microscopic analysis. LHRH, somatostatin and thyrotropin-releasing hormone could be demonstrated by alkaline phosphatase or peroxidase-antiperoxidase immunohistochemistry on semithin sections and by immunogold technique on thin sections. The LHRH secretion was close to basal values after 30 min of incubation (22.1 +/- 4.8 pg/MBH) and then remained constant for another period of 20 min (17.6 +/- 2.6 pg/MBH). During the second 20 min of incubation LHRH secretion increased in presence of 61.6 mM K+ (110.7 +/- 8.7 pg/MBH). Thus the isolated hypothalamus was excitable until the end of the in vitro incubation. We conclude that this model can be successfully used for combined morphological and functional studies.
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PMID:A model for combined morphological and functional investigations on the isolated mediobasal rat hypothalamus. 288 98

The effects of somatostatin on cholera toxin-induced secretory diarrhea and the appearance of glycoenzymes in the intestinal lumen and intestinal lymph were investigated in rat small intestine. After exposure to cholera toxin, marked fluid accumulation in the small intestinal tract and elevation of the jejunal mucosal cyclic AMP (cAMP) concentration were observed. The activity of alkaline phosphatase, aminopeptidase and sucrase increased in the intestinal lumen after toxin exposure. In intestinal lymph, alkaline phosphatase activity was increased after cholera toxin administration, while aminopeptidase activity remained unchanged. Somatostatin suppressed cholera toxin-induced secretory diarrhea, but it did not affect the elevated mucosal cAMP concentration. This peptide also inhibited the appearance of glycoenzymes in the intestinal lumen and lymph induced by cholera toxin administration. These results suggest that somatostatin exerts its inhibitory effects on cholera toxin-induced secretory diarrhea and on the appearance of glycoenzymes in the intestinal lumen and lymph by affecting processes beyond cAMP formation.
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PMID:Inhibitory effect of somatostatin on cholera toxin-induced diarrhea and glycoenzyme secretion in rat intestine. 288 40

Cysteamine and propionitrile cause severe duodenal ulcers with perforation within 24-48 h after a single injection in rats. These animal models were used to gain insight into the early, preulcerogenic biochemical changes in the duodenal mucosa. The results indicate that a single sc injection of cysteamine and propionitrile induced dose- and time-dependent decreases in the activity of phosphoprotein phosphatase (PPPase) in homogenate and particulate fractions of rat duodenal mucosa. The decrease in enzyme activity was detectable 4 h after the injection of the ulcerogens, it was maximal at 12 h, and hardly detectable at 24 h. No effect on the enzyme activity was found under in vitro conditions. PPPase activity in the liver was not influenced by either cysteamine or propionitrile. Furthermore, the toxic but nonulcerogenic derivative of cysteamine ethanolamine had no effect on PPPase in the duodenum. Thus, the effect of the duodenal ulcerogens on PPPase activity was indirect and organ specific, related only to the target organ (i.e., duodenal mucosa). The effect of the drugs was also selective at the level of mucosal cells: both duodenal ulcerogens depleted protein and alkaline phosphatase but not lysosomal acid phosphatase. The decrease of PPPase activity could be a general property of the duodenal ulcerogens since it is independent of their effect on endogenous somatostatin.
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PMID:The influence of cysteamine and propionitrile on duodenal phosphoprotein phosphatase in rats. 289 91

A hybridoma monoclonal antibody against human pepsinogen I was used to develop an enzyme-linked immunosorbent assay for pepsinogen I in serum. In the two-step competitive procedure using antimouse immunoglobulin F(ab')2 fragment coupled to alkaline phosphatase, the measurable assay range was 8-256 micrograms/l. No cross-reactivity with rat pepsinogen 1, human pepsinogen II, gastrin I, bombesin, somatostatin and peptide YY was shown. However, there was slight cross-reactivity (0.09%) with porcine pepsinogen. The coefficients of variation within and between series were 7.6% and 13.0%. This enzyme-linked immunosorbent assay for serum pepsinogen I correlated positively with radioimmunoassay (r = 0.87, n = 92). The concentration range of serum pepsinogen I in 354 healthy controls was 15-100 micrograms/l with a lognormal distribution. Serum pepsinogen I levels were significantly higher in the subjects who developed active duodenal ulcer or active gastric ulcer, but significantly lower in those who had gastric cancer, than in control subjects.
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PMID:Enzyme-linked immunosorbent assay of serum pepsinogen I. 380 50

The action of somatostatin on intestinal alkaline phosphatase activity (IAP) in the duodenal juice was examined in 22 subjects undergoing diagnostic secretin-CCK-PZ-tests. Under continuous secretin-CCK-PZ-stimulation there is an increase of IAP which is followed by a period of exhaustion after 1 h of stimulation. The intravenous administration of somatostatin induces a distinct inhibition of IAP which cannot be due to the exhaustion of the enzyme synthesis. As there is a functional relationship between fat absorption and alkaline phosphatase, it is suggested that this inhibition of IAP is one of the mechanisms of the somatostatin-induced inhibition of intestinal fat absorption.
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PMID:The action of somatostatin on intestinal alkaline phosphatase stimulated by secretin and cholecystokinin-pancreozymin. 610 6

The influence of somatostatin on discrete stages of collagenous-matrix-induced endochondral bone formation has been investigated. Local injection of somatostatin, i.e., without any measurable systemic effect, resulted in a 75% reduction of cell proliferation as measured by [3H]thymidine incorporation and ornithine decarboxylase activities. The minimum effective inhibitory dose of somatostatin was 0.25 microgram/day. Twice daily local injections of the hormone during cartilage formation also resulted in an inhibition, but this was shown to be due to impaired cell proliferation rather than to a direct effect of somatostatin on differentiation. Injection of somatostatin into developing bone tissue after the cartilage stage impaired osteogenesis, assessed by 45Ca incorporation and alkaline phosphatase activity. Concurrent injections of insulin and somatostatin obliterated the inhibitory effect of the latter on cell proliferation. Somatostatin can locally regulate the proliferation and differentiation of chondroprogenitor and osteoprogenitor cells in vivo and may directly contribute to the regulation of bone growth by its ability to counteract the stimulatory effect of insulin.
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PMID:Somatostatin can locally inhibit proliferation and differentiation of cartilage and bone precursor cells. 611 56

The effect of somatostatin on mucosal DNA, protein and brush border enzymes was studied in organ cultured rabbit jejunum and ileum. Compared to control cultures, somatostatin reduced the biopsy DNA and protein content in parallel in the jejunum, but was ineffective in the ileum. This was probably due to a direct growth inhibition, since DNA and brush border enzyme activity from desquamated cells in the postculture medium were unaffected. In addition, a direct inhibition of jejunal villous cell differentiation by somatostatin was reflected in a significant decrease of sucrase, maltase and alkaline phosphatase activity. In the ileum, only the specific activity of alkaline phosphatase was reduced. The key enzyme of cholesterol synthesis, HMG-CoA-reductase, was measured as an intracellular enzyme control and was not influenced by the hormone. The high somatostatin concentrations necessary to achieve the effects are not an artefact of hormone degradation during culture, as shown by radioimmunoassay, and suggest a local or "paracrine" rather than systemic, inhibitory action of somatostatin on intestinal growth and differentiation.
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PMID:Inhibitory effects of somatostatin on growth and differentiation in cultured intestinal mucosa. 614 52


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