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

---

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

This study was designed to assess the influence of dietary magnesium on calcium and phosphorus metabolism in growing pigs. 18 4-month-old pigs received either an Mg-deficient (40 ppm), an Mg overload (5,600 ppm) or a control Mg diet (1,000 ppm) for 70 days. The following parameters were measured: kinetics of plasma concentrations of Ca, phosphates, Mg and alkaline phosphatase (AP), absorptions, urinary and fecal excretions, retentions of Ca, P and Mg, soft tissue and bone mineral contents (BMC), and intestinal mucosal CaBP (calcium-binding protein) and AP activities. Dietary Mg level had no effect on calcium and phosphorus metabolism as far as Ca and P absorptions and retentions, BMC, intestinal CaBP and plasma levels of Ca, P and AP are concerned. Mg overload significantly decreased urinary P excretion and increased kidney P content, but did not change fecal P excretion. Jejunal AP activity was slightly decreased in Mg-deficient pigs. The plasma, bone, urinary, fecal, absorbed and retained Mg varied linearly with Mg intake (r: 0,85-0.96). In Mg-deficient pigs, hypomagnesemia appeared after 1 week and its severity did not increase with time. In Mg-overloaded pigs, hypermagnesemia occurred very late and was limited. This suggests that, in the growing pig, dietary Mg has little or no effect on Ca-P metabolism. It may also be concluded that growing pigs are rather resistant to Mg deficiency since no clinical symptoms were observed.
...
PMID:[Comparative effects of magnesium deficiency and overload on calcium and phosphorus metabolism in the growing pig]. 403 4

Duodena from 20-day-old chick embryos can be maintained in large scale organ culture on specially designed stainless-steel grids in contact with serum-free medium for 48 h with excellent preservation of mucosal structure at both the light and electron microscope levels. Although mitotic rate was subnormal, several other factors attest to the essential viability of the cultured intestine: L-leucine incorporation into protein, as well as the synthesis of a specific vitamin D(3)-induced calcium-binding protein (CaBP), increased over a 48-h culture period, and the electropotential gradient across the intestine was maintained throughout the culture period as was a concentration gradient for calcium. The tissue responded to vitamin D(3) in the medium by synthesizing the calcium-binding protein within 6 h and by exhibiting enhanced (45)Ca uptake within 12-24 h. Concentrations of vitamin D(3), or its 25-hydroxylated derivative, higher than necessary for CaBP induction, also increased the activity of alkaline phosphatase. The 1,25-dihydroxylated derivative of vitamin D(3), at a level extremely potent in CaBP induction, did not stimulate alkaline phosphatase. Mucosal to serosal transport of (45)Ca could also be measured in everted duodenal sacs, subsequent to culture under similar conditions, and was also increased by vitamin D(3) in the medium. Other embryonic organs, esophagus, stomach, liver, pancreas, lung, skin, and muscle, did not produce CaBP in response to vitamin D(3) in the culture medium. However, CaBP-synthesizing capacity was present in the entire intestinal tract, exclusive of the rectum. (59)Fe and (32)P uptake by cultured duodenum were also stimulated by vitamin D(3). The system has proven quite useful in the study of the vitamin D-mediated calcium absorptive mechanism but should be applicable to the study of the absorption of other nutrients, drugs, hormones, etc., as well as other studies of intestinal function.
...
PMID:Embryonic chick intestine in organ culture. A unique system for the study of the intestinal calcium absorptive mechanism. 435 39

The vitamin D metabolite 1,25-dihydroxyvitamin D [1,25-(OH)2D] given in vivo stimulates calcium accumulation by subsequently isolated duodenal brush border membrane vesicles (BBMV). Stimulation is rapid (within 2 h), reaching a maximum between 2-4 h. This effect occurs well before stimulation of in vivo calcium transport (2-4 h), cytosolic calcium-binding protein production (4-8 h, or alkaline phosphatase activity (8 h). No cytosolic calcium-binding protein was found in the BBMV at any time. The extent of calcium accumulation by BBMV exceeds by severalfold the predicted value based on the equilibrium distribution of glucose, indicating a substantial amount of binding. The ability of the calcium ionophore A23187 to increase the rate of accumulation suggests that this binding is intravesicular. The Eadie Hofstee analysis of the rate of calcium accumulation as a function of calcium concentration is nonlinear. At submillimolar calcium concentrations, the difference in the apparent Km for calcium accumulation by BBMV from vitamin D-deficient and 1,25-(OH)2D-treated chicks is nearly 2-fold (1.9 X 10(-4) vs. 1.1 X 10(-4)M, respectively), a difference that is not observed at higher calcium concentrations. Release of calcium from preloaded BBMV with the addition of EGTA is rapid but not complete (20-30% of the initial value after 60 min). The rapidity, but not the extent, of release is increased with A23187. BBMV from vitamin D-replete and vitamin D-deficient duodena do not differ in their rate or extent of calcium release, in contrast to their different rates of calcium accumulation. We conclude that the stimulation by 1,25-(OH)2D of calcium accumulation by BBMV is one of the earliest actions of 1,25-(OH)2D on the intestine, that this process does not involve alkaline phosphatase or cytosolic calcium-binding protein, and that influx, but not efflux, of calcium is regulated.
...
PMID:Calcium flux across chick duodenal brush border membrane vesicles: regulation by 1,25-dihydroxyvitamin D. 641 12

To determine which region of the intestinal villus was primarily responsible for calcium uptake and whether cells from the different regions of the villus differed in their response to 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3], we studied cells eluted from the duodenal villus in a sequential fashion at various times after vitamin D-deficient chicks had received 1,25-(OH)2D3. The elution scheme employed removes cells from the villus tip first and cells from the villus base last, as was documented by the distribution of alkaline phosphatase activity, sucrase activity, and cytosolic calcium-binding protein (CaBP) in the eluted fractions. Brush border membrane vesicles (BBMV) were prepared from different fractions of the villus. Calcium uptake was greatest in BBMV from cells eluted from the villus tip and least in those from the villus base. The distribution of calcium uptake and alkaline phosphatase activity in the same BBMV were parallel. After 1,25-(OH)2D3 treatment, cytosolic CaBP was observed in the cells from the villus base by 4 h and in all fractions by 8 h; at all times (from 4-24 h), cells from the villus base contained more cytosolic CaBP than did cells from the villus tip. Alkaline phosphatase activity in BBMV was stimulated in all fractions by 4 h; at all times, alkaline phosphatase activity was greatest in BBMV from cells of the villus tip. In contrast, calcium uptake by BBMV was stimulated 2 h after 1,25-(OH)2D3 administration only in cells from the villus tip and was not stimulated even by 24 h in cells from the villus base. These results indicate that the cellular response to 1,25-(OH)2D3 depends on the location of the cell on the villus and that 1,25-(OH)2D3-stimulated calcium flux across the brush border can be dissociated from 1,25-(OH)2D3-stimulated alkaline phosphatase activity and CaBP production.
...
PMID:Differential response of duodenal epithelial cells to 1,25-dihydroxyvitamin D3 according to position on the villus: a comparison of calcium uptake, calcium-binding protein, and alkaline phosphatase activity. 654 95

The relationship between bone formation and vitamin D metabolism was investigated in the developing chick embryo. Fertilized White Leghorn eggs were incubated at 38 degrees C in an incubator for 21 days. The fresh weight and calcium content of embryonic tibiae began to increase at day 12 and attained maximal values at day 19. Bone alkaline phosphatase and citrate decarboxylation activities, both of which represent osteoblastic activity, also began to increase at days 10-12, reached maximal values at day 19 and sharply declined thereafter. Both bone enzyme activities were highly correlated with CA2+-binding activity in the chorioallantoic membrane measured by the Chelex 100 assay. When mesonephric and metanephric homogenates were incubated with 25-hydroxy[3H]cholecalciferol, a marked and concomitant increase occurred in the metanephric 1 alpha- and 24-hydroxylase activity after day 14. The production of 1 alpha, 25-dihydroxycholecalciferol attained a maximal value at day 19 and decreased thereafter, whereas that of 24,25-dihydroxycholecalciferol continued to increase until hatching. The production rate of 1 alpha, 25-dihydroxycholecalciferol by the metanephros coincided with the changes in Ca2+-binding activity in the chorioallantoic membrane and osteoblastic activity. Since both intestinal calcium absorption and bone mineral mobilization do not occur in embryonic life, these results support the idea that 1 alpha, 25-dihydroxycholecalciferol may be involved directly in bone formation or induction of a calcium-binding protein in the chorioallantoic membrane.
...
PMID:Vitamin D metabolism and its possible role in the developing chick embryo. 730 73

Some markers of the intracellular systems that regulate neuronal activity and morphology were analyzed in the cerebral ganglion of hibernating snails (Helix aspersa), in comparison with active animals. The immunocytochemical expression of a calcium-binding protein, i.e. calmodulin, and some cytoskeletal components, i.e. 200 kDa phosphorylated neurofilament protein (pNFH), microtubule associated protein 2 (MAP2) and alpha-tubulin were analyzed by the use of a panel of antibodies raised against mammal antigens. Moreover, by enzymatic reactions the Ca(2+)-ATPase and alkaline phosphatase (AIPase) activities were demonstrated. In comparison with the active phase, the hibernation induced an increase in the immunopositivity for calmodulin in all the neurons. The increase may be linked to unmasking of immunoreactive epitopes due to conformational changes of the protein, which in turn may be a consequence of a reduction or absence of binding with calcium ions or of a real increase in the amount of calmodulin in the somata of neurons. In any event, both the hypotheses indicate that neurons have decreased or suppressed the Ca(2+)-dependent mechanisms as also shown by the lower Ca(2+)-ATPase activity. Nevertheless, the AIPase activity, which was localized in the epineural sheat, was not significantly changed during hibernation and this supports that some metabolic activities are preserved in the hibernated animals. Changes in the immunopositivity for cytoskeletal components were found. There was an increase in the epitopes recognized by the mammalian pNF antibody, that concerned both the positivity of the entire cytoplasm of some clusters of metacerebral neurons and the intensity of the reaction. This would be aimed to improve the stability of the somata and primary neurites. Moreover, the decrease of alpha-tubulin and MAP2 immunopositivity, suggests that a disassembly of microtubules have occurred. The findings indicate that the transport of vesicles in the axons is slowed down during hibernation. In fact, research in progress show that the patterns of neurotransmission and neuromodulation are also deeply modified.
...
PMID:The cerebral neurons of Helix aspersa during hibernation. Changes in the cytochemical detection of calmodulin, cytoskeletal components and phosphatases. 753 46

We examined the localization of neurons expressing mRNA for calretinin, a cytosolic EF hand calcium-binding protein, throughout the vestibular nuclei of rat and guinea pig by non-radioactive in situ hybridization, using an alkaline phosphatase labeled oligonucleotide probe. Labeled cells were particularly numerous in the medial vestibular nucleus (mVN) and their distribution was similar in rat and guinea pig, and presented a characteristic rostrocaudal and mediolateral pattern. The effects of hemilabyrinthectomy were assessed at various times post lesion from 10 h to 30 days by comparison of the pattern of labeling in the ipsi- and contra-lateral vestibular nuclei of guinea pig. After up to 48 h no modification in the calretinin mRNA distribution was detected. After 3 to 30 days of survival, there was a decrease (about 30%) of the calretinin expressing neurons in the nucleus on the side of the lesion. The unilateral sensory deprivation seemed to induce a permanent asymmetry in the expression of calretinin which was not abolished after vestibular compensation. These results suggested that the calretinin expression in these neurons depends upon the integrity and activity of sensorineuronal peripheral vestibular influences.
...
PMID:Distribution of calretinin mRNA in the vestibular nuclei of rat and guinea pig and the effects of unilateral labyrinthectomy: a non-radioactive in situ hybridization study. 770 61

The 1,25-dihydroxyvitamin-D3-(calcitriol)-induced medium osteocalcin and cellular osteocalcin mRNA concentrations are increased in a dose-dependent and time-dependent manner by prior treatment of the human MG-63 osteosarcoma cells with insulin-like growth factor-I (IGF-I). In addition, IGF-I reverses the inhibitory effects of dexamethasone and enhances the effects of retinoic acid on osteocalcin synthesis. The stimulatory effect of IGF-I on osteocalcin synthesis is accompanied by stabilization of osteocalcin mRNA and a decrease of AP-1 binding to the osteocalcin promoter. The binding of the vitamin-D receptor (VDR) to its cognate response element is not affected by IGF-I. In contrast to its effects on osteocalcin synthesis, both baseline and calcitriol-stimulated alkaline phosphatase activities are decreased by IGF-I treatment. Furthermore, IGF-I has mitogenic effects on MG-63 cells. The proliferation of the cells and the levels of c-jun mRNA are greatly increased during IGF-I treatment. Calcitriol reduces or eliminates both these effects. The low concentrations of IGF-I used in this study suggest that IGF-I is an important normal regulator of the synthesis of osteocalcin, a bone calcium-binding protein participating in bone mineralization, by modulating the effects of steroid hormones on its synthesis.
...
PMID:Insulin-like growth factor-1 modulates steroid hormone effects on osteocalcin synthesis in human MG-63 osteosarcoma cells. 828 40

Several growth factors, hormones and neurotransmitters, including norepinephrine, increase cellular calcium levels, promoting the translocation of cytosolic phospholipase A(2) to the nuclear envelope. This study was conducted to investigate the contributions of the calcium-binding protein calmodulin and of calcium-calmodulin-dependent protein kinase II to cytosolic phospholipase A(2) translocation to the nuclear envelope elicited by norepinephrine in rabbit aortic smooth-muscle cells. Norepinephrine caused cytosolic phospholipase A(2) accumulation around the nuclear envelope as determined from its immunofluorescence; cytosolic phospholipase A(2) translocation was blocked by inhibitors of calmodulin and calcium-calmodulin-dependent protein kinase II or calcium-calmodulin-dependent protein kinase IIalpha antisense oligonucleotide. Calmodulin and calcium-calmodulin-dependent protein kinase II inhibitors did not prevent cytosolic calcium increase but attenuated cytosolic phospholipase A(2) phosphorylation caused by norepinephrine or ionomycin. In vascular smooth-muscle cells reversibly permeabilized with beta-escin and treated with alkaline phosphatase, norepinephrine failed to cause cytosolic phospholipase A(2) phosphorylation and translocation to the nuclear envelope; these effects of norepinephrine were minimized by the phosphatase inhibitor okadaic acid. Recombinant cytosolic phospholipase A(2) phosphorylated by purified calcium-calmodulin-dependent protein kinase II, but not unphosphorylated or dephosphorylated cytosolic phospholipase A(2), introduced into permeabilized vascular smooth-muscle cells in the absence of calcium accumulated around the nuclear envelope. These data suggest that norepinephrine-induced translocation of cytosolic phospholipase A(2) to the nuclear envelope is mediated by its phosphorylation by calcium-calmodulin-dependent protein kinase II and that calcium alone is insufficient for cytosolic phospholipase A(2) translocation to the nuclear envelope in rabbit vascular smooth-muscle cells.
...
PMID:CaM kinase IIalpha mediates norepinephrine-induced translocation of cytosolic phospholipase A2 to the nuclear envelope. 1248 21

In our current investigation, we evaluated the effect of Chlorella pyrenoidosa protein hydrolysate (CPPH) and Chlorella pyrenoidosa protein hydrolysate-calcium chelate (CPPH-Ca) on calcium absorption and gut microbiota composition, as well as their in vivo regulatory mechanism in SD rats fed low-calcium diets. Potent major compounds in CPPH were characterized by HPLC-MS/MS, and the calcium-binding mechanism was investigated through ultraviolet and infrared spectroscopy. Using high-throughput next-generation 16S rRNA gene sequencing, we analyzed the composition of gut microbiota in rats. Our study showed that HCPPH-Ca increased the levels of body weight gain, serum Ca, bone activity, bone mineral density (BMD) and bone mineral content (BMC), while decreased serum alkaline phosphatase (ALP) and inhibited the morphological changes of bone. HCPPH-Ca up-regulated the gene expressions of transient receptor potential cation V5 (TRPV5), TRPV6, calcium-binding protein-D9k (CaBP-D9k) and a calcium pump (plasma membrane Ca-ATPase, PMCA1b). It also improved the abundances of Firmicutes and Lactobacillus. Bifidobacterium and Sutterella were both positively correlated with calcium absorption. Collectively, these findings illustrate the potential of HCPPH-Ca as an effective calcium supplement.
...
PMID:Effect of Chlorella Pyrenoidosa Protein Hydrolysate-Calcium Chelate on Calcium Absorption Metabolism and Gut Microbiota Composition in Low-Calcium Diet-Fed Rats. 3121 30


<< Previous 1 2 3 Next >>

---