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:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A homogeneous population of single cells from the thick ascending limb of Henle's loop (TALH) has been isolated from the rabbit kidney medulla. A total medullary cell suspension was prepared by a series of collagenase, hyaluronidase, and trypsin digestions and separated on a Ficoll gradient (2.6-30.7% wt/wt). Morphologically, the cells isolated from the TALH were homogeneous and showed polarity within their plasma membrane structure, with a few blunt microvilli on their apical surface and deep infoldings of the basal-lateral membrane. Biochemically, the TALH cells were highly enriched in calcitonin-sensitive adenylate cyclase and Na, K-ATPase. Alkaline phosphatase and arginine vasopressin-sensitive adenylate cyclase, highly concentrated in proximal tubule and collecting duct, were present only in low concentrations in the TALH cells. Additionally, furosemide, a diuretic inhibiting sodium chloride transport in the TALH in vivo, inhibited oxygen consumption of the TALH cells in a dose-dependent manner. The TALH cells were viable, as judged by morphological appearance, trypan blue exclusion, the response of oxygen consumption to 2,4-dinitrophenol, succinate and ouabain, and the cellular Na, K and ATP levels.
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PMID:Separation of renal medullary cells: isolation of cells from the thick ascending limb of Henle's loop. 625 27

We separated osteoclasts from bone and observed the effect of several known and potential mediators of the control of bone resorption on their cytoplasmic motility. We already found that calcitonin (CT), a hormone that inhibits bone resorption, regularly causes complete inhibition of cytoplasmic motility, specific for osteoclasts, through a trypsin-sensitive membrane receptor [1]. We report here that prostaglandin I2 (PGI2) and dibutyryl cyclic AMP induce an identical change in osteoclastic behavior. We found that theophylline, which inhibits intracellular cyclic AMP degradation, and which itself had no effect on osteoclastic motility, potentiated the cytoplasmic inhibition caused by CT, PGI2, and cyclic AMP. This suggests that PGI2 and CT cause cytoplasmic quiescence by increasing the intracellular level of cyclic AMP, a view compatible with the known ability of CT to increase cyclic AMP in bone [2]. Parathyroid hormone (PTH), PGE2, and 1,25 dihydroxycholecalciferol (1,25 (OH)2D3), hormones known to stimulate osteoclasts, did not stimulate the activity of either active or quiescent isolated osteoclasts. The undoubted ability of these hormones to stimulate osteoclastic activity in vivo may therefore be mediated through a primary hormonal interaction with another cell type.
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PMID:Pharmacological control of osteoclastic motility. 631 80

Osteoclasts were incubated on a glass or plastic substrate and the effect of calcitonin (CT) on their behaviour was observed. Before exposure to CT the osteoclasts were actively motile, the cytoplasm advancing behind broad pseudopodial (lamellipodial) processes which showed intense ruffling activity. CT caused cessation of lamellipodial activity within minutes, followed by gradual fragmentation and retraction of lamellipodia. Complete osteoclast quiescence was regularly induced by concentrations of CT above 50 pg/ml, and lesser degrees of quiescence were induced at concentrations down to 10 pg/ml. This quiescent state was reversed on removing CT from the medium, and was abrogated by prior treatment of osteoclasts with trypsin. The quiescent state did not reduce the longevity of the cells in culture, nor did it affect their resistance to removal from glass by trypsin. CT showed no influence on the pseudopodial activity of osteoclasts, peritoneal macrophages or inflammatory giant cells. Osteoclast quiescence seems to be a reversible state induced by the interaction of CT with a trypsin-sensitive CT receptor, present on osteoclasts. The range of concentrations which induce partial osteoclast quiescence are within the physiological range of serum concentrations in man, and this suggests that CT plays a physiological role in the regulation of osteoclasts may help to identify the precursor cell of the osteoclast and may assist investigations into the mechanism of control of osteoclasis.
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PMID:Calcitonin alters behaviour of isolated osteoclasts. 705 95

Messenger RNA extracted from rat medullary carcinoma of the thyroid directs the synthesis in cell-free translation systems of a precursor of calcitonin, Mr = 15,000, substantially larger than the mature form of the hormone, Mr = 3,500. When translations of the mRNA were carried out in the presence of microsomal membranes prepared from a canine pancreas, a larger product (apparent Mr = 17,000) was observed by electrophoresis of the labeled proteins in the translation mixtures on sodium dodecyl sulfate-polyacrylamide gels. This membrane-processed product of Mr = 17,000 was specifically immunoprecipitated by an antiserum to synthetic calcitonin and bound to concanavalin A-Sepharose. Incubation of the proteins synthesized in the cell-free translations performed in the presence of microsomal membranes with the glycosidase, endo-beta-N-acetylglucosaminidase H, reduced the apparent molecular weight of the membrane-processed precursor from 17,000 to 12,000. In addition, the processed Mr = 17,000 calcitonin-related precursor, but not the initial, unprocessed precursor of Mr = 15,000, was resistant to proteolytic digestion by a mixture of trypsin and chymotrypsin. These results indicate that the biosynthesis of calcitonin involves the glycosylation and proteolytic cleavage of a newly synthesized precursor along with sequestration of the processed precursor within microsomal vesicles. Thus, the calcitonin precursor undergoes extensive co- and post-translational processing to the smaller, unglycosylated hormone that is secreted.
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PMID:Procalcitonin is a glycoprotein. 720 75

A series of N-acylated alpha-amino acids were synthesized and shown to improve the oral delivery of two protein drugs, salmon calcitonin (sCT) and interferon-alpha. Forty-five compounds in this series were tested in vivo in rats and primates. A significant positive correlation was found between the log P of the acylated amino acids and the decrease in serum calcium following oral dosage of sCT in rats. Such a correlation was not found for interferon-alpha. These derivatized amino acids only weakly inhibited the activity of trypsin or leucine aminopeptidase. Histological examinations of rat intestinal tissue after oral dosing of acylated amino acid/protein combinations revealed no detectable pathology.
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PMID:N-acylated alpha-amino acids as novel oral delivery agents for proteins. 747 53

Mediation of postprandial pancreatic enzyme secretion has been ascribed mainly to cholecystokinin and to vagovagal reflexes. Recent studies suggest that these pathways are subject to feedback regulation. Diversion of pancreatic juice from the duodenum stimulates cholecystokinin release and pancreatic enzyme secretion, and intraduodenal administration of trypsin or chymotrypsin inhibits cholecystokinin release and pancreatic secretion. The increased plasma cholecystokinin levels following diversion of pancreatic juice seems to be mediated by "cholecystokinin-releasing factor", a trypsin-sensitive substance secreted by the proximal small intestine. This factor may mediate pancreatic enzyme secretion in response to protein intake. Dietary protein in the intestine competes for the trypsin that would otherwise inactivate the factor. The resulting increase of this factor in the intestinal lumen releases cholecystokinin and stimulates pancreatic enzyme secretion. Enteropancreatic reflex can also be activated by distension or administration of hyperosmolar solutions in the duodenum eliciting pancreatic enzyme secretion without raising plasma cholecystokinin levels. This effect is inhibited by atropine, suggesting that it is cholinergically mediated. Pancreatic response to duodenal volume or osmolality is not suppressed by trypsin, indicating that the reflex is not affected by intraluminal proteases. Our studies also show that secretion of pancreatic polypeptide is under cholinergic control, and this peptide acts by interfering with cholinergic transmission, making it an ideal candidate to modulate pancreatic secretion stimulated by the vagal cholinergic pathway. Similar observations are made with somatostatin and calcitonin-gene related peptide which also acts preferentially to inhibit pancreatic secretion by the vagal cholinergic pathway.
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PMID:Negative feedback control of exocrine pancreatic secretion: role of cholecystokinin and cholinergic pathway. 791 21

The aim of the present work was the development of a simple capillary electrophoretic strategy, complementary to high-performance liquid chromatography, for the separation of different calcitonins (CTs) and calcitonin tryptic digests. Capillary electrophoresis was carried out with a manual capillary electropherograph with "on column" UV absorbance detection at 200 nm. The separation was accomplished in a 70 cm x 50 microns I.D. bare silica capillary. About 6 nl was loaded into the capillary by means of a split-flow system. Except in particular cases, electric fields of 300 V/cm were used at constant voltage. Separations were carried out in 0.05 M citrate buffer pH 2.5 or, alternatively, in 0.05 M borate buffer pH 9.5. A complete resolution of salmon, ASU1,7-eel, and human calcitonins was obtained in citrate and borate buffers. Other CT analogues could be separated only in one of the two buffers. Capillary electrophoresis in citrate buffer was also successful in the separation of the four final trypsin cleavage fragments of salmon calcitonin and, at least tentatively, of the nine intermediate cleavage products.
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PMID:Free solution capillary electrophoresis of calcitonins and calcitonin tryptic digests. 795 19

We established a useful assay system for evaluating osteoclast-mediated bone resorption based on the use of unfractionated bone cells obtained from 10- to 11-day-old mice. When cells from 10 to 11 mice were treated for 7 days with rat parathyroid hormone (rPTH, 10(-8) M), a total of 4 to 5 x 10(7) cells could be obtained from the culture by treatment with 0.05% trypsin and 0.02% EDTA in PBS. These harvested cells contained about 20% tartrate-resistant acid phosphatase (TRAP)-positive mononuclear cells. When the harvested cells were cultured on dentine slices without rPTH, after 1 day, they formed TRAP-positive multinucleate cells that were active in bone resorption. Eel calcitonin (eCT) decreased the number of pits in a dose-dependent manner, and its half maximal inhibition dose (ID50) was 1.08 x 10(-11) M. Even after having been frozen in liquid nitrogen for 5 months, upon thawing, these cells were capable for forming pits; and this pit formation was inhibited by eCT. Since no appropriate osteoclastic cell line for evaluating bone resorption is available at present, this system can provide a useful, practical means for assaying osteoclastic bone-resorbing activity.
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PMID:Establishment of a rapid bone resorption in vitro assay using previously frozen mouse unfractionated bone cells pretreated with parathyroid hormone. 815 5

Association of stress with psoriatic skin symptoms was studied in 13 patients with psoriasis by dividing the patients into low- and high-stress groups based on their clinical examination and answers to three questionnaires (General Health Questionnaire, a somatization scale, and a life change questionnaire). This study focused on skin mast cells and sensory nerves which are the principal components in neurogenic inflammation. Mast cells were stained enzyme-histochemically for tryptase and chymase, and neuropeptides substance P (SP), vasoactive intestinal peptide (VIP), and calcitonin gene-related peptide (CGRP) were demonstrated immunohistochemically. Compared to the low-stress group (n = 7), the patients in the high-stress group (n = 6) had more severe skin and joint symptoms. Furthermore, mast cells positive for chymase activity were prominently reduced, but tryptase-positive mast cells only slightly decreased in the lesional skin of the high-stress group. A similar tendency was also observed in the nonlesional skin. In the papillary dermis of the lesional skin, both VIP- and CGRP-immunoreactive nerves could be observed in the high-stress group whereas in the low-stress group these nerve fibers were hardly visible in the corresponding area. No association of SP with stress was observed. This study suggests that psychic stress is associated with exacerbation of psoriasis, and stress may induce alterations in the psoriatic lesions by increasing the neuropeptide content with a concomitant decrease in the activity of neuropeptide-degrading enzymes, especially mast cell chymase.
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PMID:Association of cutaneous mast cells and sensory nerves with psychic stress in psoriasis. 827 75

Tryptase and chymase released from activated mast cells degrade the neuropeptides calcitonin gene-related peptide (CGRP) and vasoactive intestinal peptide (VIP) to peptide fragments. We have examined whether nedocromil sodium can modulate the ability of rat activated peritoneal mast cells to degrade 125I-CGRP and 125I-VIP. Mast cell-dependent degradation of both 125I-CGRP and 125I-VIP was observed with compound 48/80 (0.03-1 microgram/ml) and in the case of 125I-VIP with anti-IgE (1-20 micrograms/ml). Nedocromil sodium (10(-6)-10(-4) M) caused significant inhibition of neuropeptide degradation, with the most effective inhibition observed against anti-IgE-induced degradation of 125I-VIP. Nedocromil sodium had no inhibitory effect on the ability of lysed mast cells, bovine trypsin or chymotrypsin to breakdown 125I-VIP. These results suggest that nedocromil sodium inhibits mast cell-dependent degradation of neuropeptides, such as VIP, as a secondary consequence of inhibiting the release of mast cell proteases.
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PMID:The modulation by nedocromil sodium of proteases released from rat peritoneal mast cells capable of degrading vasoactive intestinal peptide and calcitonin gene-related peptide. 839 43


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