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)

Isolated hepatocytes from collagenase-perfused rat livers were used to study the hyperglycemic potential of various noncatechol sympathomimetics (NCSPM) commonly found in commercially available cough/cold preparations. The effect of various concentrations of ephedrine, pseudoephedrine, and phenylpropanolamine on glucose output were compared in dexamethasone- or saline-pretreated rats. The NCSPM produced minimal or no glucose output at most of the concentrations tested in hepatocytes from normal saline pretreated rats. However, these same compounds were able to stimulate a significant increase in glucose output from hepatocytes pretreated with dexamethasone. The results indicate that corticosteroids can enhance the glycemic potential of characteristically weak, indirectly acting NCSPM.
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PMID:Effects of noncatechol sympathomimetics on glucose output by hepatocytes from normal and dexamethasone-treated rats. 379 66

The experimental modulation of tight junctions (TJ) was studied in the human adenocarcinoma cell line HT 29 by freeze-fracture electron microscopy. The cell line has virtually no TJ when grown in culture. TJ could be induced by mild treatment with a variety of endopeptidases (trypsin, chymotrypsin, collagenase, elastase, plasmin, thrombin, papain, and pronase). Pronase induced the formation of TJ at low (but not at high) concentrations. All exopeptidases studied were unable to induce the formation of TJ. At 0 degree C the trypsin-induced formation of TJ was greatly slowed down although not entirely inhibited. However, when cells were briefly treated with trypsin at 0 degree C and subsequently transferred to 37 degrees C in the presence of protease inhibitors, TJ were rapidly assembled. Thus an induction phase at low temperature and an assembly phase at high temperature could be experimentally separated. When cells were briefly trypsinized at 0 degrees and subsequently kept at 0 degree C without trypsin for several hours, TJ still formed abundantly upon incubation at 37 degrees C. It appears therefore that the effect produced by the protease is retained for long periods in the cold.
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PMID:Formation of tight junctions in epithelial cells. I. Induction by proteases in a human colon carcinoma cell line. 388 Jul 1

1. Carp hepatocytes were isolated by dissociating the liver tissue with collagenase. The procedure yields viable cells with highly preserved ultrastructural and metabolic features. The isolated cells were able to self-aggregated and form tissue. 2. RNA and protein synthesis activity was significantly higher in the carp hepatocytes from summer acclimatized fish compared to the activity present in the cold adapted animals. 3. RNA synthesis assayed in carp hepatocytes suspensions obtained from summer and winter acclimatized fish exhibited a behaviour consistent with an inverse compensation to the cold acclimatization state, being apparently repressed, whereas protein synthesis did not show a compensatory activity.
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PMID:Behavior of RNA and protein synthesis during the acclimatization of the carp. Studies with isolated hepatocytes. 617 11

Isolation and separation of rat liver cells into endothelial, Kupffer, and parenchymal cell fractions were performed at different times after injection of human 125I-acetyl low density lipoproteins (LDL). In order to minimize degradation and redistribution of the injected lipoprotein during cell isolation, a low temperature (8 degrees C) procedure was applied. Ten min after injection, isolated endothelial cells contained 5 times more acetyl-LDL apoprotein per mg of cell protein than the Kupffer cells and 31 times more than the hepatocytes. A similar relative importance of the different cell types in the uptake of acetyl-LDL was observed 30 min after injection. For studies on the in vitro interaction of endothelial and Kupffer cells with acetyl-LDL, the cells were isolated with a collagenase perfusion at 37 degrees C. Pure endothelial (greater than 95%) and purified Kupffer cells (greater than 70%) were obtained by a two-step elutriation method. It is demonstrated that the rat liver endothelial cell possesses a high affinity receptor specific for the acetyl-LDL because a 35-fold excess of unlabeled acetyl-LDL inhibits association of the labeled compound for 70%, whereas unlabeled native human LDL is ineffective. Binding to the acetyl-LDL receptor is coupled to rapid uptake and degradation of the apolipoprotein. Addition of the lysosomotropic agents chloroquine (50 microM) or NH4Cl (10 mM) resulted in more than 90% inhibition of the high affinity degradation, indicating that this occurs in the lysosomes. With the purified Kupffer cell fraction, the cell association and degradation of acetyl-LDL was at least 4 times less per mg of cell protein than with the pure endothelial cells. Although cells isolated with the cold pronase technique are also still able to bind and degrade acetyl-LDL, it appeared that 40-60% of the receptors are destroyed or inactivated during the isolation procedure. It is concluded that the rat liver endothelial cell is the main cell type responsible for acetyl-LDL uptake.
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PMID:In vivo and in vitro uptake and degradation of acetylated low density lipoprotein by rat liver endothelial, Kupffer, and parenchymal cells. 631 44

Na+ and K+ cell contents were measured in single pieces of tubule (0.4-0.8 mm/sample) micro-dissected from the outer medulla of collagenase-treated rat kidney tissue. Extracellular cations were washed out by rinsing the tubules in ice-cold choline-chloride solution. Na+ and K+ cell contents were measured by emission flame microphotometry after appropriate treatment of the samples. Tubular volumes were calculated from photographic pictures taken before (at 4 degrees C) and after incubation of the samples. Medullary collecting tubules (MCT) and medullary thick ascending limbs of Henle (MAL) were used in this study. When kept at 4 degrees C for 2 h or more, Na+ and K+ concentrations (meq/l cell volume) were 86.3 and 30.6, respectively, in MCT and 16.2 and 94.3, respectively, in MAL. After about 5 min of incubation at 30 degrees C, MCT samples inverted their cation contents up to new steady-state concentrations (Na+ 17.4 and K+ 97.5). During incubation, the volume of MCT samples decreased slowly and in an exponential way, the rate of which was highly temperature dependent. Na+ and K+ cell concentrations in such incubated MCT samples, however, remained fairly constant between 20 and 37 degrees C. In contrast, when MAL samples were incubated at 30 degrees C, Na+ and K+ concentrations (15.9 and 90.4, respectively) remained equal to those measured at 4 degrees C and no change in volume was observed in MAL samples.
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PMID:Na+ and K+ cell concentrations in collagenase-treated rat kidney tubules incubated at various temperatures. 632 4

Naturally occurring renal adenocarcinoma in North American leopard frogs, Rana pipiens, metastasize frequently (77%) when these ectothermic animals are kept in a warm environment but not when they are kept cold. We have found that explants of these tumors secrete collagenase, an enzyme capable of dissolving connective tissue fibers and found previously to be closely correlated with metastatic colony-forming capability of murine mammary tumors, and that the amount released sequentially rises and falls as the ambient temperature is shifted between metastasis-permissive and -inhibitory levels. In contrast, normal frog renal tissue has low collagenase output, unaffected by temperature changes.
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PMID:Temperature-dependent elaboration of collagenase by the renal adenocarcinoma of the leopard frog, Rana pipiens. 633 46

A method is described which allowed in-vitro measurements of metabolic CO2 production from [U-14C]-substrates by single pieces of kidney tubules. The tubules were isolated by microdissection from collagenase treated rat kidneys. Single pieces of various distal nephrons portions were incubated in 1 microliter of bicarbonate free minimum essential medium containing the required [U-14C]-substrate (about 0.2 mu Ci per sample), and the 14CO2 produced was continuously trapped into a 2-microliter KOH droplet. The KOH droplets were replaced every 30 min. Metabolic CO2 production from the labelled substrate used was calculated as picomoles CO2 per mm of tubular length per minute, by dividing the KOH radioactivity by the specific radioactivity per carbon of the substrate present in the incubate [( U-14C] plus cold substrate concentrations). Under these conditions, it was established that single pieces of tubule could sustain almost constant CO2 production for at least 2 h at 31 degrees C. Experiments testing four different conditions with five to six replicate samples per condition were performed in order to compare oxidative metabolism in medullary (MAL) and cortical (CAL) thick ascending limbs, medullary (MCT) and cortical (CCT) collecting tubules and, in a few instances, proximal convoluted tubules (PCT) and early distal convoluted tubules (DCT).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Metabolic CO2 production by isolated single pieces of rat distal nephron segments. 643 91

Local or systemic prostaglandin (PG) administration leads to the known softening and dilatation of the cervix uteri. Lysosomal enzymes are involved in connective tissue degradation. The question arises whether the effect of PG on the cervix uteri is mediated by lysosomes. Five pregnant women (volunteers after informed consent) in the first trimester received 500 micrograms of PGE2-derivative (Nalador) i.m. at 12 and 8 h before termination by curettage. Five pregnant women without PG-treatment served as controls. Small biopsies were obtained from the endocervical canal and were immediately immersed in cold 2.5% glutaraldehyde and after further preparations examined under a Zeiss electron microscope 9S-2. A second portion of tissue was sliced and prepared for histochemical analysis of the acid phosphatase on lysosomes. Examination of the ultrastructure of the cervix uteri showed vesicles in the extracellular matrix. These were surrounded by a single membrane and contained either fine granular material of myelin-like whorls of membranes. These vesicles lay between collagen fibers, showed the reaction product of acid phosphatase and were often surrounded by an electron-lucent halo. We conclude that these matrix vesicles were "matrix lysosomes" extruded from the cervical myo-fibrocytes into the extracellular space as a result of the PG-E2-administration. Here they are not under cellular control and can initiate the proteolytic degradation of connective tissue. This might be the crucial step in cervical dilatation which, on ultrastructural examination, can be seen as decreasing electron density of the extracellular ground substance near the matrix lysosomes. The relationship between PGE2 and collagenase production is generally accepted. If one believes that lysosomal cathepsin D and cathepsin B act synergistically with collagenase, it can be assumed that PGE2 is involved in a lysosomal degradation of the connective tissue. The morphological sign of this occurrence is the release of matrix lysosomes by PGE2 as described in the present study. Extracellular lysosomes and their physiological significance in cervical function are discussed in detail.
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PMID:The effect of prostaglandins on the lysosomal function in the cervix uteri. 666 Sep 24

Hepatocytes were isolated by collagenase perfusion of the liver from adult eels (Anguilla anguilla L.) acclimated to different temperatures. Whereas the relative weight of the liver increased in cold-acclimated fish, hepatocytes from 10- and 20 degrees C-acclimated animals did not differ in cellular weight, dry weight, or protein content. Endogenous rates of oxygen consumption and respiratory control ratios were independent of acclimation temperature. There was no effect of temperature on triacylglycerol content, but glycogen concentration was significantly higher in hepatocytes of cold-acclimated fish. Liver cells from cold-acclimated eels exhibited higher rates of glucose release and ketogenesis than those from warm-acclimated animals. It is concluded that the increase in acetoacetate production induced by cold acclimation results primarily from a higher rate of lipolysis. Cellular interactions between ketogenesis and gluconeogenesis are demonstrated and discussed.
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PMID:Influence of thermal acclimation on glucose production and ketogenesis in isolated eel hepatocytes. 672 Sep 21

Hepatocytes prepared by collagenase perfusion from Antarctic nototheniid fish of genus Trematomus are active in uptake of [14C]leucine at 0, 5, and 10 degrees C. The system is saturable with apparent Km about 1.0 mM. Isoleucine and phenylalanine were major competitors, valine was about one-half as effective, while alanine, glycine and histidine had no effect. Temperature dependency of rates in the 0-10 degrees C range yielded Ea = 65 kJ/mol (Q10 = 2.7). The average first-order rate constant at 0 degrees C was 0.1 min-1, one-third the value of 0.3 min-1 estimated for clearance of [14C]leucine by liver of these species in vivo. Affinity and specificity agreed well with in vivo data on liver clearance of leucine, both in Antarctic fish at 0 degrees C and in temperate fish acclimated to 10 degrees C and 20 degrees C. The results indicate similar modifications of leucine transport associated with evolutionary cold adaptation and seasonal acclimation in fish.
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PMID:Characteristics of leucine transport by isolated hepatocytes of Antarctic fish at low temperatures. 717 5


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