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:3.4.24.3 (collagenase)
18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Using the isolated perfused in situ rat adrenal preparation, we have shown a direct stimulatory action of calcitonin gene-related peptide on aldosterone secretion. The threshold dose for this action was 1 pmol, given as a bolus in 200 ul. CGRP also caused vasodilation in the adrenal gland, reflected in increased perfusate flow, and also stimulated corticosterone secretion, with a threshold of 0.1 pmol. Addition of CGRP to incubations of collagenase-dispersed adrenocortical cells had no effect on steroidogenesis. These results support the contention that CGRP, which have been identified in nerve terminals in the zona glomerulosa of the rat adrenal cortex, may have a role in the control of steroid secretion.
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PMID:Calcitonin gene-related peptide stimulates adrenocortical function in the isolated perfused rat adrenal gland in situ. 208 1

In UMR 106 rat osteosarcoma cells, parathormone (1-34hPTH) and calcitonin (sCT) stimulated adenylate cyclase (AC) activity 5.5-and 2.8-fold, respectively. AC in osteoblasts (OB) from collagenase-treated calvaria of 3-day-old rats responded similarly to 1-34hPTH. In contrast, fibroblasts (mouse fibroblastomas) displayed a marginal 1-34hPTH sensitive AC. Osteoclasts (OC) of collagenase-treated rat calvariae, rat monocytes and mouse macrophages did not demonstrate 1-34hPTH inducable AC activity. Physiological concentrations of 24,25-dihydroxyvitamin D-3 attenuated PTH-sensitive AC in OB and UMR 106 cells within 20 min, while 1,25-dihydroxyvitamin D-3 showed no such immediate effect. In contrast, the AC response to Gpp(NH)p was unaffected by 24,25-(OH)2D3, indicating that 24,25-(OH)2D3 interrupts the coupling of the PTH receptor to the GTP binding protein Gs. OB and UMR 106 cells were also subjected to long-term (48 h) incubation with vitamin D-3 metabolites, 1-34hPTH or 20% serum from patients with secondary hyperparathyroidism (sHBT-serum), respectively. PTH-sensitive AC was markedly attenuated by pre-exposure to both 1-34hPTH and 1,25-(OH)2D3, while minimally affected by corresponding 24,25-(OH)2D3 and 20% sHPT-serum treatment. The secretion of alkaline phosphatase (Alphos) from the two cell types was strongly increased by 1-34hPTH, the effect being abolished by the presence of 24,25-(OH)2D3. Iliac crest biopsies of normal individuals exhibited a clear negative correlation between PTH-sensitive AC and corresponding serum 24,25-(OH)2D3 levels. Basal AC activity was, however, negatively correlated to serum 1,25-(OH)2D3 concentrations. In summary, the results show that 24,25-(OH)2D3 reduces PTH-stimulated AC activity in and Alphos secretion from osteoblastic bone cells by rapidly and directly interfering with the plasma membrane. These data reinforce the probable in vivo significance of 24,25-(OH)2D3. Moreover, the negative correlation between basal AC activity and serum 1,25-(OH)2D3 levels indicates a possible role for 1,25-(OH)2D3 in regulating bone cell synthesis of AC components in vivo.
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PMID:1,25-dihydroxyvitamin D-3 and 24,25-dihydroxyvitamin D-3 affect parathormone (PTH) -sensitive adenylate cyclase activity and alkaline phosphatase secretion of osteoblastic cells through different mechanisms of action. 216 95

In this study, we determined the effects of indomethacin and calcitonin on bone resorption in otosclerosis-like lesions in rats. Morphometric analysis showed that both indomethacin and calcitonin inhibited active otosclerosis-like lesions (bone resorption) and rats immunologically induced with type II collagen, and indomethacin had a much higher inhibitory effect than calcitonin. In in vitro studies we found that conditioned medium from splenic lymphocytes of rats immunized with type II collagen stimulated collagenase production by macrophages and fibroblasts. Collagenase is the major enzyme for degradation of the organic components of bone. Treatment of the immunized rats with indomethacin and calcitonin significantly reduced the stimulatory effect of the lymphocyte-conditioned medium on collagenase production. Indomethacin caused a greater reduction of the stimulatory effect of the lymphocytes on collagenase production than calcitonin. These findings are in agreement with results of the morphometric study. Results of the present study also suggest that cell-to-cell interaction plays an important role in collagenase production for degradation of organic components of bone resorption in otosclerotic lesions.
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PMID:Effects of indomethacin and calcitonin on bone absorption in type II collagen-induced otosclerosis-like lesions in rats. 217 35

Mixed bone cell cultures obtained by sequential collagenase-trypsin digestion of newborn chick, rat, and mouse calvaria responded to calcitonin gene-related peptide (CGRP) with a dose-dependent increase in cyclic AMP formation. The amplitude of response to CGRP in each species was less than that to parathyroid hormone (PTH). The CGRP effect was not the result of an action as a weak calcitonin agonist, since in most instances a calcitonin effect was not observed. Only in early digests of mouse calvarial cells were consistent stimulatory effects of calcitonin on cyclic AMP noted, and these were always considerably less in amplitude than those to CGRP. It is concluded that chick, rat, and mouse bones contain cells in osteoblast-rich populations that respond specifically to CGRP with a rise in cyclic AMP.
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PMID:Effects of calcitonin gene-related peptide on cyclic AMP formation in chicken, rat, and mouse bone cells. 254 86

Proximal tubules were prepared from rat kidney cortex by collagenase digestion and purified by Percoll gradient centrifugation. Their enrichment was estimated by comparing the specific activities of various cell-specific enzymes in homogenates of renal cortex and of the isolated tubules. The tubules were cultured in a 50:50 mixture of Dulbecco's modified Eagle's and Ham's F12 media supplemented with insulin, transferrin, epidermal growth factor, hydrocortisone, and prostaglandin E1. After 2 to 3 d an extensive outgrowth of epithelial cells developed from the attached tubules. After 5 to 7 d near confluent monolayers were obtained. Hormonal responsiveness, marker enzyme activities, and transport properties were determined to further characterize the primary cultures. The cultured cells exhibited increased cyclic AMP production in response to parathyroid hormone but not calcitonin or vasopressin, consistent with the absence of cells derived from distal and collecting tubules. The cells also retained significant levels of 25-hydroxyvitamin D3-1 alpha-hydroxylase, alkaline phosphatase, and gamma-glytamyl-transpeptidase, three enzymes that are primarily associated with the proximal tubule. The cultured epithelial cells also exhibit a Na+-dependent phosphate and glucose transport systems. Therefore, the cells retain many functional properties that are characteristic of proximal tubules. Thus, the primary cultures should be suitable for the study of processes that occur specifically within this segment of the rat nephron.
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PMID:Characterization of primary cell cultures derived from rat renal proximal tubules. 254 89

The participation of collagenase in bone resorption has been investigated by assaying the procollagenase extracted from fetal mouse calvaria cultured under a variety of conditions, and by evaluating its ability to degrade bone collagen. Procollagenase was found in two separate pools, one requiring demineralization for its extraction, the other not. Culturing the bones with PTH, 1,25-dihydroxyvitamin D3, prostaglandin E2, interleukin-1, tumor necrosis factor-alpha, catabolin, retinoic acid, or endotoxin (but not with heparin) induced resorption, enhanced lysosomal enzyme release, and markedly increased the procollagenase content of the second pool. The PTH-induced increase in procollagenase was dose dependent and paralleled the extent of calcium loss and lysosomal enzyme release. The increase in procollagenase was found in bone, periosteum, and sutures, where its distribution was similar to that of nonmineralized collagen. The increase in procollagenase was abolished by cycloheximide, but not by indomethacin, hydroxyurea, glucocorticoids, acetazolamide, bisphosphonates, or calcitonin. Calcitonin and bisphosphonates almost completely inhibited the PTH-induced Ca loss and lysosomal enzyme release, but only partially inhibited the PTH-induced loss of collagen. The latter was, however, completely prevented by the collagenase inhibitor, CI-1. CI-1 also partially inhibited the PTH-induced Ca loss. Moreover, collagen degradation occurred in PTH-precultured calvaria (but not in noncultured controls) when incubated in a buffer under nonviable and nondemineralizing conditions. This degradation was inhibited by collagenase inhibitors, either CI-1 or the natural tissue inhibitor of metalloproteinases. This work thus indicates that the resorption of fetal bone explants proceeds along with an accumulation of procollagenase, primarily within their nonmineralized matrix. Moreover the results suggest that collagenase is likely to participate in the degradation of the nonmineralized collagen of the bone explants. Whether it also participates in the degradation of the collagen of the mineralized matrix remains to be elucidated.
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PMID:Bone-resorbing agents affect the production and distribution of procollagenase as well as the activity of collagenase in bone tissue. 283 55

It has previously been demonstrated that somatostatin (SRIF) directly inhibits parietal cell secretion. However, the significance of SRIF as a paracrine agent and mechanisms of local gastric SRIF release are not clear. Vasoactive intestinal peptide (VIP) and calcitonin gene-related peptide (CGRP) are neuropeptides which have been localized in the gastric fundus and have been demonstrated to inhibit gastric acid secretion in vivo. The present study examines the hypothesis that CGRP and VIP act via the release of gastric fundic SRIF. The study utilized rabbit isolated gastric glands prepared by collagenase digestion. Glands were incubated alone, or with 10(-10)-10(-6) M CGRP or 10(-10)-10(-6) M VIP for 30 min. Supernatant SRIF was measured using a specific radioimmunoassay. Unstimulated SRIF release was 101 +/- 16 fmole/ml. CGRP (10(-7) and 10(-6) M) and VIP (10(-7) and 10(-6) M) resulted in significant SRIF release. The maximum release of SRIF by CGRP (506 +/- 113 fmole/ml) was significantly greater than that by VIP (293 +/- 33 fmole/ml) (P less than 0.05). However, both these concentrations of SRIF are comparable to the ID50 concentration (4.5 X 10(-10) M) for SRIF inhibition of acid secretion by isolated parietal cells as assessed by [14C]aminopyrine accumulation. These results are consistent with the hypothesis that CGRP and VIP inhibition of acid secretion may be mediated, at least in part, by the local release of SRIF from the gastric fundus. These data further support the significance of paracrine interactions in the modulation of cellular secretory function.
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PMID:Gastric somatostatin release: evidence for direct mediation by calcitonin gene-related peptide and vasoactive intestinal peptide. 289 38

A primary culture of mammalian parafollicular cells was established from rat thyroid glands in order to investigate the effects of serotonin and somatostatin on calcitonin secretion. Minced rat thyroid glands were dissociated with collagenase and cultured in a Ham's F-12K medium supplemented with calf serum (5%), insulin (1.3 X 10(-6) mol/l), hydrocortisone (10(-8) mol/l), transferrin (6.1 X 10(-9) mol/l), and glycyl-L-histidyl-L-lysin (2.5 X 10(-8) mol/l). Immunohistochemical peroxidase-antiperoxidase method revealed that the cultured parafollicular cells were immunopositive for human calcitonin, and electron microscopy demonstrated the existence of dense secretory granules in the cultured parafollicular cells. Addition of the Ca2+ to the culture medium stimulated calcitonin secretion from the cells dose-dependently as measured by radioimmunoassay. Pre-incubation of serotonin with the cells produced higher calcitonin levels in a dose-dependent manner. On the other hand, pre-incubation of somatostatin with the cells significantly inhibited calcitonin secretion.
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PMID:Effects of somatostatin and serotonin on calcitonin secretion from cultured rat parafollicular cells. 289 90

A mouse monoclonal antibody designated IgG3(rct-30) has been prepared that reacts specifically with an antigen on the surface of all cells comprising the cortical and medullary rabbit renal collecting tubule including the arcades. Plastic culture dishes coated with IgG3(rct-30) were used to isolate collecting tubule cells from collagenase dispersions of rabbit renal cortical cells by immunoadsorption. Typically, 10(6) rabbit cortical collecting tubule (RCCT) cells were obtained from 5 g of renal cortex (2 kidneys). Initial purity was greater than 96% based on immunocytofluorescent staining with three different anti-collecting tubule antibodies. Between 20 and 30% of the RCCT cells were reactive with peanut lectin suggesting that RCCT cells are a mixture of principal and intercalated cells. Approximately 10(7) RCCT cells were obtained after 4 to 5 days in primary culture. Moreover, RCCT cells continued to proliferate after passaging with a doubling time of approximately 32 h. RCCT cells passaged once and then cultured 4-5 days were found 1) to synthesize cAMP in response to arginine vasopressin (AVP), prostaglandin E2 (PGE2), isoproterenol, and parathyroid hormone, but not calcitonin, prostaglandin D2, or prostaglandin I, and 2) to release PGE2 in response to bradykinin but not arginine vasopressin or isoproterenol. Our results indicate that cultured RCCT cells retain many of the hormonal, histochemical, and morphological properties expected for a mixture of principal and intercalated rabbit cortical collecting tubule epithelia. RCCT cells should prove useful both for studying hormonal interactions in the cortical collecting tubule and as a starting population for isolating intercalated collecting tubule epithelia.
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PMID:Immunodissection and culture of rabbit cortical collecting tubule cells. 301 26

This paper describes a rapid and simple method for isolation of medullary thick ascending limbs (MTAL) from rat kidney. The technique takes advantage of the fact that MTAL represents a high fraction of the inner stripe (IS) tissue in the outer medulla, and that this nephron segment is more resistant than others to mechanical and enzymatic disruption. Special attention was given in the design of each step of the isolation procedure in order to improve purity and yield of the preparation. Major steps are the following: careful dissection of the IS; cutting IS tissue into small pieces of regular size (approximately equal to 1 mm3); mild and brief enzymatic hydrolysis in a 65 U/ml collagenase solution; separation of long MTAL segments from other tubule fragments and cells, and washing of the collagenase solution, on a nylon sieve (100 microns opening). This technique does not require lengthy centrifugations and provides about 6 mg fresh tissue (= 1 mg protein) from two rat kidneys in 2 h. Light microscopy and transmission electron microscopy show a good purity (at least 95%) and good preservation of TAL ultrastructural morphology. Adenylate cyclase responsiveness to arginine-vasopressin (AVP), glucagon (GLU) and salmon calcitonin (SCT) of the MTAL suspension is similar to that reported for single microdissected rat MTAL. Viability of the MTALs was demonstrated by the ability to accumulate cyclic AMP in presence of AVP, GLU, SCT and forskolin. Normal oxygen consumption was 45.1 +/- 2.4 (SEM) microliter . mg protein-1 . h-1 (n = 8).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Quick isolation of rat medullary thick ascending limbs. Enzymatic and metabolic characterization. 301 64


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