Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.1.3 (ATPase)
 65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the search for a functional role for the polarized glycoconjugates of rat collecting duct epithelial cells, the relation between binding of various lectins and expression of cellular transport enzyme profile of the cells was studied. For this purpose, principal and intercalated cells of rat kidney collecting duct were identified by morphological criteria and by their immunocytochemically determined content of (Na+ + K+)-ATPase and carbonic anhydrase (CA II), respectively. Various N-acetylgalactosamine-specific lectins such as those from Helix pomatia and Maclura pomifera revealed heterogeneity among both principal and intercalated cells, whereas alpha-N-acetylgalactosamine-specific lectin from Dolichos biflorus and Vicia villosa bound preferentially to principal cells. Still another lectin from Arachis hypogaea reacted with most collecting duct cells in the cortex and outer medulla, but only with a subpopulation of cells in the inner medulla. Interestingly, some lectins reacted exclusively with the apical aspect of the collecting duct epithelial cells, whereas others revealed both an apical and basolateral distribution of lectin reactive glycoconjugates. The results thus show subtle differences in the glycocalyx structure of principal and intercalated cells and differences in the intracellular polarization of glycoconjugates of these cells. Thus, lectins may be useful tools in the study of the molecular mechanisms which establish and maintain the polarized functions of principal and intercalated cells.
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PMID:Heterogeneity of apical glycoconjugates in kidney collecting ducts: further studies using simultaneous detection of lectin binding sites and immunocytochemical detection of key transport enzymes. 285 98

The mesonephric kidney, precursor to the metanephric kidney, comprises 30-50 nephrons, each with a glomerulus and proximal, distal, and collecting tubules. Although two different cell types have been identified in the mesonephric collecting tubule, no relationship to cells of the metanephric collecting duct has been established. To characterize expression of some of the acid-base-related proteins, we assayed for carbonic anhydrase (CA) activity and performed immunocytochemistry in mesonephroi from 15- to 20-day-old fetal rabbits. From total RNA, we detected expression of CA II and CA IV mRNA. Microdissected proximal and collecting tubules abundantly expressed both CA II and CA IV, at least to the extent observed in mature metanephric proximal tubules and collecting ducts. Histochemistry confirmed the expression of CA activity in these segments; in the collecting tubule, 28% of the collecting tubule cells were CA rich. Most CA-rich cells showed apical H(+)-ATPase and basolateral band 3 anion exchanger staining consistent with the findings in mature H(+)-secreting (alpha) intercalated cells of the metanephric collecting duct. CA-negative cells could be labeled with an antibody that identifies mature metanephric principal cells. Thus the mesonephric collecting tubule has many cells resembling mature alpha-intercalated cells and a majority of cells resembling principal cells. The similarity to the metanephric collecting duct suggests that the lineages of metanephric alpha-intercalated and principal cells may be closely related to those of the mesonephros.
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PMID:Expression of acid-base-related proteins in mesonephric kidney of the rabbit. 781 Jul 7

Intercalated cells are present in both the collecting duct, which is derived from the ureteric bud, and the connecting tubule (CNT), which is part of the nephron and thus is developed from the metanephric blastema. However, the embryologic origin of the intercalated cells has not been established. Two populations of intercalated cells, type A and type B, exist in the CNT and the cortical collecting duct (CCD). It is uncertain, however, whether these cells represent truly distinct cell types or whether one is derived from the other. In this study we have used specific antibodies to carbonic anhydrase II (CA II), H(+)-adenosinetriphosphatase (H(+)-ATPase), and band 3 protein to identify subpopulations of intercalated cells, to determine the site and time of their appearance, and to follow their differentiation in the developing rat kidney. Prenatal kidneys from 16-, 17-, 18-, and 20-day-old fetuses, and postnatal kidneys from 0-, 3-, 7-, 14-, and 21-day-old pups were preserved for immunohistochemical studies. Immunostaining for CA II and H(+)-ATPase appeared simultaneously in a subpopulation of cells in the CNT and the medullary collecting duct (MCD) of the 18-day-old fetus, suggesting that intercalated cells differentiate from separate foci, one in the nephron and one in the collecting duct. Cells with apical and cells with basolateral labeling for H(+)-ATPase appeared in the CNT and MCD at 18 days of gestation, indicating that type A and type B cells differentiate simultaneously during renal development. Band 3 immunostaining was very weak in the fetal kidney, but a striking increase in labeling was observed in the 3-day-old kidney, suggesting that there is an activation of acid-secreting cells shortly after birth. In the fetal kidney, immunostaining for CA II and H(+)-ATPase was observed in cells throughout the MCD and on the papillary surface. After birth, immunostaining gradually disappeared from both the papillary surface and the terminal inner MCD, and cells with basolateral labeling for H(+)-ATPase gradually disappeared from the outer MCD. The results of this study suggest that type A and type B intercalated cells represent distinct cell types that derive from undifferentiated cells at two separate foci, one in the nephron and one in the collecting duct. Our results also suggest that entire populations of intercalated cells are eliminated from the collecting duct during normal renal development.
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PMID:Differentiation of intercalated cells in developing rat kidney: an immunohistochemical study. 802 77

The gastric mucosa secretes both protons and bicarbonate. The molecular identity of the H(+)-K(+)-ATPase, which mediates acid secretion, has long been known, but the other components of the secretory machinery and their cellular disposition are less well characterized. This study identifies and localizes in rat and rabbit gastric mucosa a chloride-bicarbonate exchanger protein and a Na(+)-H+ exchanger protein. The previously described band 3-related protein of the parietal cell has been identified by isoform-specific antibodies as anion exchanger (AE) 2 and localized to the basolateral membranes of the parietal cells. The Na(+)-H+ exchanger protein NHE-1 was located in the basolateral membranes of the mucous neck cells, interdigitated between the parietal cells of the gastric glands and in the basolateral membranes of the surface mucous cells. Neither transporter protein was abundantly expressed deep in the gland, where most of the pepsinogen cells reside. Carbonic anhydrase II (CA II) was expressed at higher abundance in the surface mucous cells and mucous neck cells, which expressed NHE-1, than in the parietal cells, which expressed AE2. The morphological evidence identified AE2 as a major parietal cell anion exchanger, whereas NHE-1 and CA II colocalized in mucous neck, chief, and surface mucous cells. We propose that all three of these cell types contribute to gastric bicarbonate secretion.
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PMID:Immunolocalization of anion exchanger AE2 and cation exchanger NHE-1 in distinct adjacent cells of gastric mucosa. 814 Dec 71

The bone resorbing cells, osteoclasts, express high levels of carbonic anhydrase II (CA II) and vacuolar H(+)-ATPase (V-ATPase) during bone resorption. We have used antisense RNA and DNA molecules targeted against CA II, and against 16- and 60-kD subunits of vacuolar H(+)-ATPase (V-ATPase), to block the expression of these proteins in vitro. Osteoclastic bone resorption was studied in two in vitro culture systems: release of 45Calcium from prelabeled newborn mouse calvaria cultures, and resorption pit assays performed with rat osteoclasts cultured on bovine bone slices. Both antisense RNA and DNA against CA II and the V-ATPase were used to compare their specificities as regards inhibiting bone resorption in vitro. The antisense molecules inhibited the synthesis of these proteins by decreasing the amounts of mRNA in the cells in a highly specific manner. In osteoclast cultures treated with the 16-kD V-ATPase antisense RNA, acidification of an unknown population of intracellular vesicles was highly stimulated. The acidification of these vesicles was not sensitive to amiloride or bafilomycin A1. This suggests the existence of a back-up system for acidification of intracellular vesicles, when the expression of the V-ATPase is blocked. Our results further indicate that blocking the expression of CA II and V-ATPase with antisense RNA or DNA leads to decreased bone resorption.
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PMID:Inhibition of bone resorption in vitro by antisense RNA and DNA molecules targeted against carbonic anhydrase II or two subunits of vacuolar H(+)-ATPase. 820 Sep 64

The expression of laminin, Na+, K(+)-ATPase, carbonic anhydrase (CA) isoenzymes and calcitonin gene-related peptide (CGRP) in the human fetal vestibular ganglia was studied by immuno-histochemistry. In the 12-week-old fetus, the cell surface of the vestibular ganglion cells was positive for laminin. In the 14-week-old fetus, a few vestibular ganglion cells were positive for CA II. In the 15-week-old fetus, the cell surface of the vestibular ganglion cells and the nerve fibers were strongly labelled with laminin. CGRP positive nerve fibers were found in the ganglia. In the 16-week-old fetus, some ganglion cells were labelled with Na+, K(+)-ATPase. CA II stained the vestibular nerve fibers as well as the vestibular ganglion cells. The results suggest that these substances may be used as histological markers of maturation and innervation of the human vestibular ganglion cells.
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PMID:The expression of maturation factors in the vestibular ganglia in the human fetus. 838 67

Immobilization causes a transient increase in bone resorption and a prolonged depression of bone formation. We have studied the effect of immobilization on the expression of two proteins believed to have a major functional role in osteoclasts, the proteolipid subunit of vacuolar H(+)-ATPase (VPL) and carbonic anhydrase II (CA II). Trabecular bone from immobilized rat tibiae was analyzed using northern and slot blotting, polymerase chain reaction (PCR), and morphometric analysis. CA II and VPL transcription was rapidly stimulated in trabecular bone of immobilized rat tibiae. Osteoclast number increased and the trabecular bone volume decreased during immobilization. Fluorescein-labeled cDNA probes and a confocal laser scanning microscope were used to study the localization of VPL and CA II mRNAs in situ in osteoclasts and other bone-derived cells attached to bovine bone slices in vitro. CA II and VPL mRNA were highly expressed in actively resorbing osteoclasts, but in nonresorbing osteoclasts mRNA expression was very low or not detectable at all. These results strongly suggest that both CA II and VPL have an important functional role in bone resorption. Finally, in the bone cell population isolated for these studies, CA II was found to be highly specific for osteoclasts whereas VPL was also detected in other cell types.
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PMID:Proton channel part of vacuolar H(+)-ATPase and carbonic anhydrase II expression is stimulated in resorbing osteoclasts. 842 45

The activity of gastric parietal cells in terms of hydrochloric acid (HCl) secretion is regulated by the interaction of stimulatory substances (e.g. gastrin) and inhibitors (e.g. somatostatin) acting in an endocrine and paracrine mode, as well as luminal factors. In the present study the following parameters were measured: the synthesis (mRNA), storage (tissue peptide concentration) and secretion (plasma peptide concentration) of somatostatin and gastrin following short-term treatment of rats with pentagastrin (acid stimulant), secretin, omeprazole (reduces gastric acidity by inactivating gastric H/K ATPase) and the somatostatin analogue octreotide (reduces gastric acidity by inhibiting both the parietal cell and gastrin). The mRNA coding for H/K ATPase and carbonic anhydrase II (CA II), the two enzymes responsible for the generation of hydrogen ions from the parietal cell, were also quantitated. In response to octreotide, somatostatin peptide and mRNA levels in the fundus rose to 180 +/- 16% (P < 0.001) and 1073 +/- 356% (P < 0.05) of control, respectively. In contrast, octreotide caused a decrease in antral somatostatin peptide and its mRNA did not change significantly. No significant changes in synthesis, secretion or storage of gastrin were observed except for omeprazole induced hypergastrinaemia (580 +/- 76%, P < 0.001). H/K ATPase and CA II mRNA were largely unaffected except for an increase in CA II mRNA following octreotide and a decrease in H/K ATPase mRNA after pentagastrin. These data support the concept of the differential control of antral and fundic somatostatin synthesis and provide evidence for a regulatory loop by which somatostatin can influence its own synthesis.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Secretory and biosynthetic responses of gastrin and somatostatin to acute changes in gastric acidity. 852 6

Osteopetrosis in laboratory animals is a metabolic bone disease characterized by increased skeletal mass. It is inherited as an autosomal recessive and results from a defect in the development and/or function of osteoclasts. We studied two enzymes essential for bone resorption, carbonic anhydrase II isoenzyme (CA II) and H+ -ATPase, in osteoclasts from four osteopetrotic mutations in the rat; namely incisors-absent (ia), osteopetrosis (op), toothless (tl), and microphthalmia (mib), to test the hypothesis that reduced bone resorption in one or more of these mutations results from defects in the synthesis or activity of one of these enzymes. CA II was present in most osteoclasts from normal, tl, op, and mib littermates and was homogeneously distributed in cytoplasm. CA II staining in ia osteoclasts was more variable and less intense than in the other mutations. H+-ATPase was also present in osteoclasts from normal animals and mutants and immunostaining showed clear polarization to the ruffled border region in all normal rats and mutants except ia, which showed diffuse distribution of staining in the cytoplasm. H+-ATPase activity (proton transport) in a related tissue, kidney, was normal in tl and ia rats but increased in op and mib rats compared to their normal littermates. These results suggest that the osteoclasts in osteopetrotic rat mutations are not abnormal with respect to the distribution of CA II and H+ -ATPase and that the function of these enzymes in the skeleton, while likely normal, needs to be tested directly in bone.
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PMID:Carbonic anhydrase II and H+ -ATPase in osteoclasts of four osteopetrotic mutations in the rat. 993 Aug 84

In this study our experiments followed in vitro and in vivo the effect of omeprazole on purified and erythrocyte carbonic anhydrase (CA) I and II isozymes, as well as on gastric mucosa CA IV in humans. Our in vitro results show that omeprazole-induced inhibition of purified CA I and CA II and gastric mucosa CA IV is dose- and pH-dependent. In vivo, the i.v. administration of omeprazole in humans in therapeutic doses produced a decrease in erythrocyte CA I and CA II activity, as well as in gastric mucosa CA I, II, and IV. Regarding CA IV, the results lead to the conclusion that omeprazole selectively inhibits gastric mucosa CA IV and does not modify the activity of the same isozyme from the kidney and lung, indicating organ specificity. Our results strongly suggest that omeprazole has a dual mechanism of action: H(+)K(+)ATPase inhibition and gastric mucosa CA inhibition, and that these enzymes may be functionally coupled. This 2-fold mechanism of action could explain the greater effectiveness of substituted benzimidazoles as compared with other therapies.
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PMID:Omeprazole has a dual mechanism of action: it inhibits both H(+)K(+)ATPase and gastric mucosa carbonic anhydrase enzyme in humans (in vitro and in vivo experiments). 1041 59


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