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)

Alkaline phosphatase activity and calbindin-D9K immunoreactivity are decreased in the intestines of spontaneously hypertensive rats (SHRs). To investigate the potential role of altered gene expression in these decreases, we measured, by Northern blot analyses, the abundances of alkaline phosphatase and calbindin-D9K mRNAs in the proximal regions of the small intestines of 14-week-old SHR and control Wistar-Kyoto (WKY) rats. Alternate 4-cm segments of intestine were used for measurements of the proteins (0-4 cm, 8-12 cm, and 16-20 cm from pylorus, segments A1, B1, and C1, respectively) and mRNAs (4-8 cm, 12-16 cm, and 20-24 cm, segments A2, B2, and C2). Calbindin-D9K (immunoassay) was decreased in SHR vs WKY rats by 27%, 64%, and 67% in segments A1, B1, and C1, respectively (P < 0.01); its mRNA was decreased to a similar extent (69%, 82%, and 80%, respectively; P < 0.002 by analysis of variance). Alkaline phosphatase activity was decreased in SHRs by 58%, 54%, and 51% in segments A1, B1, and C1, respectively (P < 0.01); the abundance of its 3.0-kb mRNA was decreased to a similar extent: 57%, 80%, and 69% in segments A2, B2, and C2, respectively (P < 0.02). The mean decreases of the 2.7-kb mRNA of alkaline phosphatase were statistically significant (P < 0.02) but smaller (38%, 40%, and 35%). The mean abundance of vitamin D receptor mRNA in the same animals was decreased slightly in SHR vs WKY rats (3%, 36%, and 20% in segments A2, B2, and C2, respectively), but the difference in the values was not statistically significant. Decreases in alkaline phosphatase activity and calbindin-D9K immunoreactivity may reflect decreased mRNA abundance and not decreased enzyme-specific activity or increased protein degradation.
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PMID:Decreased abundance of alkaline phosphatase and calbindin-D9K mRNAs in the intestine of the spontaneously hypertensive rat. 133 19

Parvalbumin and calbindin, two calcium binding proteins in the nervous system, are present in certain neuronal subpopulations. In the present study a method for a simultaneous demonstration of the both antigens was developed, which labels parvalbumin- and calbindin-containing structures in contrasting colours. A horseradish peroxidase-conjugated second antibody was used for the visualization of the monoclonal anticalbindin antibody, whereas the biotinylated anti-parvalbumin antibody was demonstrated by means of a biotin-streptavidine-alkaline phosphatase system. The method may be useful to classify neuronal populations and to study their morphological relationship.
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PMID:Parvalbumin and calbindin immunoreactivity in the rat brain: a double-immunolabelling method. 158 78

Untreated diabetic (BB) rats exhibited compensatory intestinal growth which was associated with hyperplasia and was accompanied by an increase in unoccupied vitamin D receptors. Although vitamin D receptors were increased, low circulating 1,25-dihydroxy-vitamin D3 [1,25(OH)2D3] prevented amplification of the action of 1,25(OH)2D3, as evidenced by reductions in calbindin D-9K and alkaline phosphatase activity in the BB rat intestine compared to control. In the kidney, a lesser degree of compensatory growth was observed which was not associated with hyperplasia, and no significant effect of diabetes on vitamin D receptors or calbindin D-28K was observed. These studies suggest tissue-specific changes in 1,25(OH)2D3 metabolism during spontaneous diabetes which may be related to the hyperplasia which occurs during compensatory tissue growth.
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PMID:Vitamin D receptors and compensatory tissue growth in spontaneously diabetic BB rats. 165 63

The small number of hair cells in auditory and vestibular organs severely impedes the biochemical characterization of the proteins involved in mechano-electrical transduction. By developing an efficient and clean "twist-off" method of hair bundle isolation, and by devising a sensitive, nonradioactive method to detect minute quantities of protein, we have partially overcome this limitation and have extensively classified the proteins of the bundles. To isolate hair bundles, we glue the saccular macula of the bullfrog to a glass coverslip, expose the tissue to a molten agarose solution, and allow the agarose to solidify to a firm gel. By rotating the gel disk with respect to the fixed macula, we isolate the hair bundles by shearing them at their mechanically weak bases. The plasma membranes of at least 80% of the stereocilia reseal. To visualize the proteins of the hair bundle, we covalently label them with biotin, separate them by SDS-PAGE, and transfer them to a charged nylon membrane. We can detect less than 500 fg of protein by probing the membrane with streptavidin-alkaline phosphatase and detecting the chemiluminescent product from the hydrolysis of the substrate 3-(4-methoxyspiro-(1,2-dioxetane-3,2'-tricyclo-[3.3.1. 1(3.7)]decan)-4-yl) phenyl phosphate (AMPPD). These techniques reveal a distinct constellation of proteins in and associated with hair bundles. Several proteins, such as calmodulin, calbindin, actin, tubulin, and fimbrin, have previously been described. A second class of proteins in the preparation appears to be derived from extracellular sources. Finally, several heretofore undescribed bundle proteins are identified and characterized by their membrane topology, subcellular localization, and glycosidase and protease sensitivities.
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PMID:High-purity isolation of bullfrog hair bundles and subcellular and topological localization of constituent proteins. 170 75

Intestinal Ca2+ malabsorption has been described in spontaneously hypertensive rats (SHRs), but the molecular basis for this defect is unknown. In this study, we measured intestinal alkaline phosphatase and vitamin D-dependent Ca(2+)-binding protein (calbindin-D9k), two proteins implicated in the active pathway of intestinal Ca2+ absorption. Both proteins were measured in the small intestines of SHRs and their normotensive controls, Wistar-Kyoto rats, before, during, and after development of hypertension (4, 9, 14, 18, and 28 wk of age). At all ages, alkaline phosphatase activity in duodenum (0-6 cm) was decreased by 30-57% (P less than 0.001) and by 47-75% in the 2nd intestinal segment (6-12 cm) (P less than 0.001-0.05). Calbindin-D9k was decreased similarly. The decreases of calbindin were statistically significant (P less than 0.001-0.05) in the duodena at 4, 14, 18, and 28 wk (9-30% decreases) and in the 2nd segment at 4, 14, and 18 wk (38-69% decreases; P less than 0.001-0.005). Decreased calbindin in SHRs was documented in animals from two suppliers. The deficiencies of calbindin-D9k and alkaline phosphatase could not be attributed to malnutrition or to a generalized brush-border defect as indicated by body weights and the intestinal marker enzyme sucrase. Although calbindin-D9k was decreased in young SHRs, the serum 1,25-dihydroxycholecalciferol [1,25(OH)2D3] was increased by 59 and 129% in 4- and 9-wk-old SHRs (P less than 0.001), respectively; by contrast, serum 1,25(OH)2D3 was unchanged or decreased in older SHRs.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Intestinal vitamin D-dependent calbindin-D9k and alkaline phosphatase in spontaneously hypertensive rats. 203 38

Dietary lead intake was demonstrated to result in two very different effects on intestinal calcium absorption and associated parameters, depending on dietary calcium status. Normal growing 14-day-old chicks were fed diets either low (0.05%) or adequate (1.2%) in calcium and containing varying levels of lead (0%-0.8%) for an additional 10 days. In chicks fed the low calcium diet, ingested lead inhibited intestinal 47Ca absorption, and intestinal calbindin D and alkaline phosphatase synthesis in a dose-dependent fashion. Even at the highest levels of lead, however, this inhibition was limited to the stimulation of these parameters by low dietary calcium. In chicks fed the normal calcium diet, lead exposure did not diminish intestinal 47Ca absorption, or calbindin D or alkaline phosphatase synthesis, but actually elevated the values of these parameters at the higher lead exposure levels. The results indicate that the primary effect of lead, in both cases, occurs at or prior to intestinal protein synthesis and most likely involves the cholecalciferol endocrine system rather than any direct interactions between lead and calcium at the intestinal level.
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PMID:Effect of dietary calcium and lead status on intestinal calcium absorption. 215 38

The intestinal absorption of calcium is certainly a complex process, dependent on several factors of which vitamin D, via 1,25(OH)2D3, is the major controlling hormone. The efficiency of calcium absorption is a function of calcium status and calcium need. As the body's demand for calcium increases, the process commonly termed, adaptation, is activated in which the synthesis of 1,25(OH)2D3 from precursor is increased, resulting in the stimulation of the rate of calcium absorption. The increased demand for calcium might result from the ingestion of a diet deficient in calcium, from growth, pregnancy, lactation and egg shell formation in the laying hen. Accomapanying the change in calcium absorptive efficiency are molecular modifications of the transporting enterocytes, some mentioned herein and elsewhere (Wasserman & Chandler, 1985; Wasserman, 1980; Wasserman et al., 1984). Highly correlated with the rate of calcium absorption under a wide variety of conditions is the concentration of the vitamin D-induced calcium-binding protein, calbindin-D28K (avian type) and calbindin-D9K (mammalian intestinal type). The role of calbindin-D in this transport process is not precisely known but is considered to act at the present time as a cytosolic facilitator of Ca2+ diffusion from the brush border membrane to the basolateral membrane. In addition to the induction of calbindin-D synthesis, 1,25(OH)2D3 exerts other effects on the intestinal epithelium that can have consequences on the calcium absorptive process. Some of these effects are summarized in Figure 14. Vitamin D-dependent reactions might be either direct effects of 1,25(OH)2D3 or indirect effects due to elevated intracellular Ca2+ concentrations. These include changes in the fluidity of the brush border membrane, an increase in microvillar alkaline phosphatase-low affinity Ca-activated ATPase activity, an association of calmodulin with the 105 kD brush border cytoskeletal protein and, following calbindin D synthesis, the binding of calbindin D to a 60 kD brush border protein and to microtubules. The latter has been suggested to be related to the proposed transfer of Ca2+ by an endocytotic-exocytotic mechanism. In addition, a vitamin D-dependent intestinal membrane calcium-binding protein has been identified (Kowarski & Schachter, 1980). Playing into this multi-component system is a stimulation of cyclic nucleotide synthesis by 1,25(OH)2D3 which, through activation of cyclic nucleotide-dependent protein kinases, might modify membrane Ca2+ "channels" by phosphorylation reactions.4+ Intracellular organelles, i.e., the endoplasmic reticulum, mitochondria, the Golgi apparatus, are potent sequesters of Ca2+ and could contribute to the protection of the cell from excessively high Ca2+ concentrations by transiently storing absorbed Ca2+.
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PMID:On the molecular mechanism of intestinal calcium transport. 254 94

Enterocytes are the major epithelial cell type of the small intestine. Their capacity to secret, absorb and digest specific ions and nutrients is dependent on their position along the length of the small intestine as well as their stage of development as they migrate and differentiate along the crypt-villus axis. In order to further understand the molecular processes that regulate enterocyte differentiation and function, this study has compared the levels of six mRNA species produced by genes expressed in rabbit enterocytes; specifically, the multidrug resistance (MDR1) gene encoding the 170-kDa P-glycoprotein, CaBP 9k, which encodes a putative intracellular calcium buffer, calbindin, LPH, APN, and AP which encode the brush-border hydrolases lactase-phlorizin hydrolase, aminopeptidase N and alkaline phosphatase, respectively, and SGLT1, encoding the brush border Na(+)-glucose cotransporter. The level of each mRNA species has been mapped along the small intestine using quantitative in situ hybridisation. This has revealed characteristic regional variations in the abundance of each of the mRNAs, supporting the opinion that there is a strong genetic component to the maintenance of gradients in epithelial function along the length of the small intestine. Analysis of the cellular accumulation of mRNA during enterocyte migration along the crypt-villus axis, over gut-associated lymphoid tissue, and at epithelial boundaries, has, by contrast, established a clear correlation in the expression of these genes. These data illustrate the dynamics of enterocyte gene expression, thereby providing an insight into the molecular mechanisms which co-ordinate the events of cell transformation that underlie functional differences between the epithelial populations of the small intestine.
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PMID:Parallel patterns of cell-specific gene expression during enterocyte differentiation and maturation in the small intestine of the rabbit. 758 2

We describe a method to combine non-radioactive in situ hybridization using alkaline phosphatase (AP) labelled oligonucleotide-probes with immunohistochemistry on the same thin paraffin section. The simultaneous detection of calretinin-mRNA and calbindin- or tyrosine hydroxylase-like immunoreactivity in neurons of rat substantia nigra, pars compacta, was used as a test system to develop the method. Brains were fixed by perfusion with 4% paraformaldehyde and embedded in paraffin. Five-microns-thick sections were processed for non-radioactive in situ hybridization with a 33-base alkaline phosphatase conjugated synthetic oligonucleotide complementary to calretinin mRNA. After hybridization and colour reaction to visualize calretinin mRNA, sections were incubated with antibodies against calbindin D28K or tyrosine hydroxylase. Immunoreaction was visualized using the avidin-biotin-complex-technique and diaminobenzidine. As the colour of both reaction products differ markedly, the distribution of calretinin mRNA-containing neurons (purple-blue, alkaline phosphatase product) and calbindin/tyrosine hydroxylase immunopositive cells (brown peroxidase product) could be differentiated easily on the same section. Calbindin- and tyrosine hydroxylase-like immunoreactivity was found in the majority of calretinin mRNA-containing cells within the substantia nigra, pars compacta, indicating that in this nucleus a proportion of the dopaminergic neurons contain both calcium binding proteins calbindin and calretinin. In conclusion, non-radioactive in situ hybridization using alkaline phosphatase labelled oligonucleotide probes can be readily combined with immunohistochemistry.
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PMID:Combination of alkaline phosphatase in situ hybridization with immunohistochemistry: colocalization of calretinin-mRNA with calbindin and tyrosine hydroxylase immunoreactivity in rat substantia nigra neurons. 790 17

A monoclonal antibody produced against the human erythrocyte plasma membrane calcium pump (PMCA) was shown to react immunohistochemically with an epitope of the PMCA in avian and mammalian cerebellum. Western blot analysis of purified synaptosomes and homogenates from avian cerebellum revealed major immunoreactive proteins with molecular masses (130 kDa and 138 kDa) similar to those of purified erythrocyte PMCA. Dual-imaging confocal immunofluorescence microscopy of avian cerebellum showed that the PMCA antibody stained the periphery of the soma whereas calbindin-D28k was located in the cytosol. PMCA heavily stained the more distal dendrites of the Purkinje cells and, within the resolution of the fluorescence procedure, colocalized with calbindin-D28k. By using alkaline phosphatase-conjugated second antibody, PMCA was again localized to the peripheral soma, to a segmental pattern in dendrites, and to presumed spiny elements. The soma periphery and dendrites of Purkinje cells of the rat cerebellum were also prominently stained with anti-PMCA antibody and compared to parvalbumin localization. Dendritic depolarization and dendritic spiking behavior are significant Ca(2+)-dependent events of Purkinje cells. The rapid decline of intracellular free Ca2+ after the rapid rise time of Ca2+ transients is considered to be due to sequestration by Ca2+ buffers, uptake by intracellular stores, and Ca2+ extrusion mechanisms, the latter a function of PMCA now shown immunohistochemically to be a prominent feature of Purkinje cell dendrites.
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PMID:Immunocytochemical localization of the plasma membrane calcium pump, calbindin-D28k, and parvalbumin in Purkinje cells of avian and mammalian cerebellum. 826 54


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