Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.3 (collagenase)
 18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Adenyl cyclase activity of rat pancreatic islet membrane was increased by secretin, pancreozymin, and isoproterenol, while ACTH, glucagon, growth hormone, and insulin had no effect. Both secretin and isoproterenol activations were enhanced by prostaglandin E1 (PGE1) and GTP. Isoproterenol activation was additive with PGE1, as was that of secretin with PGE1, but only in the presence of GTP. Secretin activation in the presence of PGE1 and GTP was equivalent to NaF stimulation. Kinetic analysis indicated that secretin and GTP increased the maximum velocity of the adenyl cyclase and tended to decrease the apparent affinity of the enzyme for ATP. Glucagon activation of islet membrane adenyl cyclase was dependent upon prior treatment of the membrane preparation with EGTA and the use of inhibitors of proteolytic enzymes during the collagenase digestion phase of islet preparation. These results suggest that hormonal regulation of insulin secretion may be affected by PGE1 and guanine nucleotide modulation of the adenyl cyclase activation process.
 ...
PMID:Hormonal regulation of pancreatic islet adenyl cyclase. 17 51

Five different cell populations, designated I to V, were isolated from minced newborn rat calveria by 5-sequential 20 min incubations with an enzyme mixture containing collagenase, elastase and DNAse. In primary culture, all five populations responded to parathyroid hormone (PTH) to a different degree, population IV giving the highest increase in cyclic-3'5'-adenosine monophosphate (cAMP) level. None of the five populations gave any response to calcitonin. Upon subsequent subcultures, all populations, except population IV, either lost or considerably decreased their response to PTH. Population IV gave a two to three-fold increase in cAMP concentration in response to PTH up to the third subculture. No morphological differences could be observed among the five populations. The third subculture of population IV cells that had been stored in 10% glycerol at -80C for four months was subsequently thawed and subcultured to the sixth subculture. These cells still responded to PTH with an increase in cAMP level. In a second experiment, 5 different cell populations designated I to V were isolated in a similar way by incubation with collagenase and DNAse. The maximum response to PTH was found in population 3. The preservation of the PTH-responsiveness of this population, after subculturing, freezing, storing in 10% glycerol at -80 C and subsequent subculturing, was likewise demonstrated. The hormone-responsiveness of cells from the sixth subculture of previously frozen and thawed population IV cells was further analyzed. These cells responded to PTH at a concentration of 0.1 U/ml to 5U/ml and to prostaglandin E1 (PGE1) at a concentration of 0.1 microng/ml to 10 microng/ml. The time course of action on population IV of PTH was found to be different from that of PGE1, suggesting a possible difference in the regulation of intracellular cAMP levels by these hormones.
 ...
PMID:Parathyroid hormone- and prostaglandin E1-response in a selected population of bone cells after repeated subculture and storage at -80C. 19 Dec 37

The production of collagenase (EC 3.4.24.3) by endotoxin-stimulated macrophages was significantly inhibited by indomethacin, indicating that prostaglandins (PGs) mediate this effect. Inhibitions of collagenase production by indomethacin was overcome by addition of exogenous PGE2 at 10 nM whereas the addition of 0.1 and 1.0 micrometer PGE2 increased the enzyme production to 3 times that achieved by endotoxin. Although the addition of prostaglandin alone to macrophage cultures did not stimulate collagenase production, the simultaneous addition of PGE1 or PGE2 and endotoxin enhanced collagenase activity 2- to 10-fold. This increase was detectable at PGE concentrations of 10 nM and was optimal at 0.1-1.0 micrometer. PGF2alpha had little effect on either the enhancement of collagenase production by endotoxin-stimulated macrophages or its restoration in cultures inhibited by indomethacin. Radioimmunoassay of prostaglandins in the culture media revealed that macrophages exposed to endotoxin secreted 40-fold more PGE2 than did unstimulated cells. The increase in PGE2 was detected 4 hr after exposure to endotoxin and was maximal at 14 hr. The peak PGE2 concentrations in the culture media were similar to those of exogenous PGE2 (about 10 nM) needed to restore collagenase production in indomethacin-treated cultures. These findings demonstrate the involvement of PGE in the endotoxin-activation of macrophages with resultant production of collagenase.
 ...
PMID:Prostaglandin regulation of macrophage collagenase production. 20 Sep 41

We have developed a preparation of monolayer cultures of bovine parathyroid cells in order to elucidate the control mechanism of the biosynthesis and secretion of parathyroid hormone (PTH) at cellular level. Dispersion of parathyroid cells was performed by stirring minced bovine parathyroid tissues in Hanks' BSS containing 0.3 yields to 0.5 percent collagenase at 37 degrees C for 60 min. Dispersed cells were cultured at 37 degrees C in MEM-Hanks' BSS containing 10 percent fetal calf serum and 15 mM HEPES. On the 5th day of the culture, the medium was replaced with 1 percent BSA-MEM-Hanks-HEPES buffer, and the cells were incubated with 3H-leucine or in the media containing various concentrations of calcium, magnesium, PGE1, PGE2 or DBcAMP. At the end of incubation, the cells were detouched and homogenized in 8M urea, 0.2 N HCL and 0.01 M cysteine solution. The isolation of proparathyroid hormone (ProPTH) and PTH was performed through the preparation of TCA-powder followed by CMC column chromatography. PTH in the incubation medium was determined by radioimmunoassay. It was demonstrated that the monolayer cultures of bovine parathyroid cells were synthesizing ProPTH and converting it to PTH. The cultures exhibited linear secretion rates of PTH into the medium. The secretion of PTH was markedly increased by PGE1, PGE2 or DBcAMP in the range of 10(-7) yields to 10(-5)M in the former and 10(-5) yields to 10(-3)M in the latter, while calcium or magnesium changed secretion rate in the range of 0.3 yields to 4.4 mM.
 ...
PMID:[Studies on the biosynthesis and secretion of parathyroid hormone in monolayer cultures of bovine parathyroid cells (I) (author's transl)]. 20 10

Selected properties of [3H]prostaglandin (PG) E1 binding to collagenase dispersed bovine luteal cells were studied and compared with those observed in luteal plasma membranes. [3H]-PGE1 specific binding to a relatively homogeneous population of luteal cells was a rapid (K1 = 4.2 X 10(5) M-1 .sec-1), reversible (K-1 = 3.9 X 10(-3) sec-1), saturable and specific process at 38 degrees C. The binding was homogeneous with an apparent dissociation constant of 2.4 nM and 1.8 X 10(5) receptors per cell. The presence of increasing amounts of unlabeled PGs inhibited [3H]PGE1 binding in a dose-dependent manner. The potency order for this inhibition of binding was: PGE 2 greater than PGE1, (15S)-15-methyl-PGE2 methyl ester greater than PGF2alpha greater than PGF1alpha greater than other PGs, PGE, PGF metabolites and PGF analogs. Other than the homogeneous nature of [3H]PGE1 binding and the greater effectiveness of PGE2 compared to PGE1 in cells, the rest of the properties of [3H]PGE1 binding to cells were in excellent agreement with those observed in plasma membranes.
 ...
PMID:Selected properties of [3H]prostaglandin E1 binding to dispersed bovine luteal cells. 20 3

To evaluate the hypothesis that extracellular mediators may affect collagen production by mesenchymal cells via a cyclic AMP coordinated mechanism, normal human fibroblasts were exposed to a variety of agents (prostaglandin E1, isoproterenol, cholera toxin) which independently elevated intracellular cyclic AMP during a 6-h incubation. Concomitantly, each agent caused an average 47% reduction in the percentage of total protein synthesis represented by collagen, yet little change in other major extracellular proteins. Since no active collagenase was found in these cultures, these findings suggest cyclic AMP levels may modulate the differentiated state of normal fibroblasts with respect to collagen production.
 ...
PMID:Association in normal human fibroblasts of elevated levels of adenosine 3':5'-monophosphate with a selective decrease in collagen production. 20 41

The secretory response of pituitary gonadotropes to stimulation by gonadotropin-releasing hormone (GnRH) has been extensively studied, but the mechanism by which GnRH evokes gonadotropin synthesis and release has not been clarified. In particular, there has been conflicting evidence about the role of cAMP in GnRH-induced release of LH. To examine this question in more detail, the actions of GnRH on LH release and cAMP production were analyzed in primary cultures of collagenase-dispersed rat pituitary cells. In this system, addition of 10(-10)--10(-6) M GnRh to cultured pituicytes caused rapid release of LH into the incubation medium. In contrast, GnRH caused no significant change in intracellular or extracellular cAMP or in occupancy by cAMP of the regulatory subunit of protein kinse. Neither dibutyryl cAMP nor methyl isobutylxanthine (MIC) stimulated LH production to the same level as GnRH, and neither agent potentiated the effect of the releasing hormone. Cholera toxin and prostaglandin E1 (PGE1), both of which stimulated cAMP production in cultured pituicytes, did not raise LH levels as markedly as GnRH. These results demonstrate the independence of LH release from cAMP accumulation in cultured pituicytes, suggesting that cAMP is not required for stimulation of LH release from these cells and that GnRH acts on LH secretion by a different mechanism.
 ...
PMID:Gonadotropin-releasing hormone action in cultured pituicytes: independence of luteinizing hormone release and adenosine 3',5'-monophosphate production. 22 Nov 78

Adenylate cyclase activity in particulate fractions from a transplantable rat osteogenic sarcoma was stimulated in a dose-dependent manner by prostaglandins E1 and E2 (PGE1 and PGE2) and parathyroid hormone (PTH). Prostaglandin F2alpha was active at a high concentration (3 x 10(-4) mol/l). Pretreatment of membranes with collagenase plus hyaluronidase reduced the magnitude of the PTH effect but did not affect the size of the PGE1 effect. Guanosine 5'-triphosphate and its synthetic analogue 5'-guanylylimidodiphosphate (Gpp(NH)p) activated adenylate cyclase in particulate preparations from the osteogenic sarcoma. The latter agent produced much larger effects, although the concentrations required for half-maximal enzyme activation were the same for both agonists (approximately 2 x 10(-6) mol/l). The effects of PTH and Gpp(NH)p were supra-additive at some concentrations of hormone. The effects of PGE1 and Gpp(NH)p were supra-additive at all hormone concentrations tested. Pre-incubation of membrane particles for 6 min with PTH produced an enzyme activation which was not reversed by dilution through washing; pre-incubation with PGE1 did not produce this effect. The response of membrane adenylate cyclase to Gpp(NH)p (10(-4) mol/l) was 75% greater in preparations pre-incubated with PTH than in membranes pre-incubated in buffer alone or in buffer containing PGE1. The basal rate of cyclic AMP production in the adenylate cyclase assay system decreased over a 35 min incubation period. This decrease was prevented by addition of PTH or PGE1. Addition of NaF or Gpp(NH)p produced a steady increase in the rate of production of cyclic AMP with time. Membrane preparations did not reduce the biological activity of PTH and did not degrade 125I-labelled PTH. The results demonstrate that the PTH- and PGE-responsive adenylate cyclases of the osteogenic sarcoma have distinctly different properties and that particulate preparations of the tumour do not metabolize PTH.
 ...
PMID:Membranes from a transplantable osteogenic sarcoma responsive to parathyroid hormone and prostaglandins: regulation of adenylate cyclase and of hormone metabolism. 27 36

The effect of prostaglandins (PG) A1, E1, E2 and F2 alpha in the concentration range of 10(-7)--10(-4) M were studied in vitro on a rat hypothalamic tissue, collagenase-digested isolated anterior pituitary cell and Leydig cell suspension system by measuring the testosterone production of incubated Leydig cells. PGs did not change the testosterone production and the hCG sensitivity of the Leydig cells, nor the LH secretion and the LHRH sensitivity of the anterior pituitary cells. PGE2 at concentrations of 10(-6), 10(-5) and 10(-4) M significantly increased the hypothalamic tissue-induced pituitary-testicular activation, and this stimulatory effect of PGE2 was dose dependent. PGA1, PGE1 and PGF2 alpha did not alter hypothalamic LHRH release measured in vitro. The results suggest that PGE2 has a direct stimulatory effect on hypothalamic LHRH release.
 ...
PMID:Effect of prostaglandins on hypothalamic-pituitary-testicular function in vitro. 39 65

The involvement of leukocytes in corneal neovascularization has been known for a long time. Recent observations suggest that collagenase from leukocytes may be a common mediator for prostaglandin E1 (PGE1)- and copper-induced corneal neovascularization. This study was designed to investigate the effect of copper ion on collagenase activity from leukocytes and other sources and leukocyte infiltration in the corneal angiogenic process induced by PGE1. These results demonstrated that collagenase production from leukocytes was stimulated in a dose-dependent manner by copper ion but not by PGE1. Copper chloride 0.2 mM produced the highest stimulation. Copper ion had no effect on collagenase release from corneal fibroblasts and capillary endothelium. There were more polymorphonuclear leukocytes (PMN) in the prostaglandin E1 treated corneas than in the control. The time-course study showed that the appearance of PMN reached a peak on day 2 and new vessel growth could not be identified until day 4. These results supported an earlier suggestion that leukocytes play a role in corneal neovascularization and further suggested that copper in corneal neovascularization can stimulate the release of collagenase from leukocytes.
 ...
PMID:Effect of copper ion on collagenase release. Its implication in corneal vascularization. 131 69


1 2 3 4 5 Next >>