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)

Collagenase-liver-perfusion technique, currently used with adult rat liver, was applied to isolation of hepatocytes from suckling rat liver. The total hepatocyte numbers isolated from suckling rats by collagenase-liver-perfusion technique were 9-fold higher than those by non-perfusion technique. The yield and viability of isolated hepatocytes from suckling rats were 18.1 X 10(7) cells per gram liver and 95%, respectively. The cell yield per gram liver and viability from suckling rats were 185% and 112% of those from adult ones, respectively. In comparison with adult rat hepatocytes, suckling rat hepatocytes were smaller and more homogeneous. The percentage (3.1%) of binucleate cells in the hepatocytes isolated from suckling rats was about one tenth of that (30.7%) in the hepatocytes isolated from adult rats. The isolated suckling rat hepatocytes had higher tyrosine aminotransferase (TAT) and glucose-6-phosphate (G6Pase) activities than adult ones. Suckling and adult rat hepatocytes were transferred to primary culture to compare their cell number kinetics and functional longevities. The functional longevities of those hepatocytes were assessed by their capacity to secrete albumin and alpha-fetoprotein (AFP) into the culture medium and to express TAT and G6Pase activities up to day 6 of primary culture.
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PMID:Perfusion technique of suckling rat liver, and comparison of cytologic and biochemical properties between hepatocytes isolated from suckling and adult rats. 242 63

In an attempt to understand the mechanism by which estrogens stimulate cell proliferation and mammary carcinogenesis, metastatic human breast cancer cell lines (MCF7, ZR75-1) were found to secrete a 52,000 dalton (52K) protein under estrogen stimulation. Following its purification to homogeneity, the 52K protein was identified as a secreted procathepsin-D-like aspartyl protease bearing mannose-6-phosphate signals. This precursor displays an in vitro autocrine mitogenic activity on estrogen-deprived MCF7 cells and is able to degrade basement membrane and proteoglycans following its autoactivation. The total protease (52K + 48K and 34K) was detected and assayed by monoclonal antibodies and was found to be highly concentrated in proliferative and cystic mastopathies. In breast cancer, its cytosolic concentration appears to be correlated more to tumor invasiveness than to hormone responsiveness. The mRNA of the 52K protease accumulates rapidly following estradiol treatment, as was shown by Northern blot analysis with cloned cDNA. The 52K cathepsin-D-like protease is the first example of a lysosomal protease induced by estrogens in cancer cells. Results obtained using different approaches suggest that two cysteinyl cathepsins are also related to cell transformation and invasiveness. It has been proposed that cathepsin-B is involved in breast cancer and metastatic melanoma, and its regulation by estrogen has been shown in the rat uterus. Cathepsin-L corresponds to the major excreted protein (MEP) whose synthesis and secretion are markedly increased by transformation of NIH 3T3 cells with Ki ras and are regulated by several growth factors. In addition to secreted autocrine growth factors and to other proteases (plasminogen activator, collagenase), lysosomal cathepsins may therefore play an important role in the process of tumor growth and invasion as long as their precursor is secreted abundantly.
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PMID:Estrogen-induced lysosomal proteases secreted by breast cancer cells: a role in carcinogenesis? 331 45

Radiochemical microprocedures were developed for the determination of hexokinase and phosphoenolpyruvate carboxykinase (PEPCK) activity in single microdissected segments of the mature rabbit nephron dissected from fresh tissue after collagenase treatment. All results were related to tubular length and tubular protein content. Hexokinase activity was found to be lowest in the proximal convoluted tubule and to increase along the following nephron segments, with highest activity in the connecting tubule. The gluconeogenic enzyme PEPCK, on the other hand, was exclusively found in the proximal tubule. Early and late portions of the convoluted segment exhibited the same specific activity, but only 50% was found in the pars recta. All other renal structures exhibited only insignificant activity of PEPCK. The results show that renal glucose metabolism and gluconeogenesis are clearly separated. As previously shown for the cytosolic rat enzyme, rabbit mitochondrial PEPCK is also exclusively a proximal tubular enzyme, thus confirming the dominant role of this segment in mammalian renal gluconeogenesis. The high activity of hexokinase in the segments of the distal tubule points to the role of glucose as metabolic fuel, glycogen precursor, and other glucose-6-phosphate-using pathways in these structures.
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PMID:Distribution of hexokinase and phosphoenolpyruvate carboxykinase along the rabbit nephron. 724 39

The effect of glucose-6-phosphate (G-6-P) and pH on glucose transport was studied in skeletal muscle plasma membrane giant vesicles containing GLUT4 but not GLUT1. Vesicles (average diameter 7.6 microns) were obtained by collagenase treatment of muscle. The vesicles were incubated with 10 mmol l-1 G-6-P and, after 0.5 and 2 h of incubation, the intravesicular G-6-P concentration was 0.93 +/- 0.4 mmol l-1 and 1.18 +/- 0.5 mmol l-1 (mean +/- SE, n = 4), respectively. In order to increase the intravesicular G-6-P concentration, 0.001% saponin was added during incubation, which increased the 2-h intravesicular G-6-P concentration to 4.57 +/- 1.0 mmol l-1 (n = 4). Initially, vesicles were used for glucose transport studies after 30 min of incubation with 10 mmol l-1 of G-6-P. There was no effect of G-6-P on either the affinity constant (Km) or maximal velocity (Vmax) of the glucose transport. Subsequently, vesicles were incubated for 2 h with 10 mmol l-1 of G-6-P and 0.001% saponin. Still no effect of G-6-P on glucose transport could be detected. In contrast, the rate of D-glucose transport was affected, when extravesicular pH was varied from 6.0 to 7.8. The maximum glucose transport rate was found at pH 7.2 and was decreased at both higher and lower pH. It is concluded that G-6-P has no effect on GLUT4 intrinsic activity in rat skeletal muscle plasma membrane. In contrast, GLUT4 intrinsic activity is sensitive to changes in pH.
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PMID:Effect of glucose-6-phosphate and pH on glucose transport in skeletal muscle plasma membrane giant vesicles. 819 2

It was the aim of the present study to characterize the hemodynamic, biochemical and morphologic effect of angiotensin II receptor blockade on hypoxia-induced right ventricular hypertrophy in rats. Isolated right ventricular hypertrophy was induced in female Sprague-Dawley rats by intermittent hypoxia (IH; 10% O2, 8 h/day, 5 days/week, 20 days of exposition, n=15). After completion of IH, left- (LV) and right-ventricular (RV) hemodynamic parameters were measured under room air conditions in the intact, thiopental-anesthetized animals with special Millar ultraminiature tipcatheter-manometers. Cardiac output was determined using the thermodilution method. Cell volume (CV) of isolated cardiomyocytes was measured with a Coulter Channellyzer after collagenase cell isolation. The specific activities of the myocardial pentose phosphate pathway enzymes glucose-6-phosphate-dehydrogenase (G-6-PD) and 6-phosphogluconate-dehydrogenase (6-PGD) were determined using a spectrophotometric assay. IH caused a rise in right ventricular systolic pressure (RVSP) from 38.1+/-0.83 to 58.1+/-1.42 mmHg and an increase in the RV weight/body weight ratio (RVW/BW) from 0.884+/-0. 053 to 1.166+/-0.049 mg/g. The activities of G-6-PD and 6-PGD were significantly increased after IH in the RV, but not in the LV. CV was increased from 24 248+/-1193 to 29 541+/-1765 micrometer 3, myocardial cell length was unchanged. IH had no influence on the LV parameters or cardiac output. Co-infusion of the angiotensin II receptor antagonist losartan (LO; 12 mg/kg/d i.p., n=14) during the IH period reduced the rises in RVSP (49.4+/-2.06 mmHg), RVW/BW (0. 99+/-0.072 mg/g), G-6-PD and 6-PGD significantly, but not completely. The increase in CV, however, was prevented (24 524+/-2370 micrometer 3) entirely. We conclude from these data that the IH-induced RV-hypertrophy was primarily of the concentric type. LO attenuated the hypoxia-induced isolated RV hypertrophy and significantly reduced the metabolic response of the RV. The LO effect was most potent with regard to the increase in cardiomyocyte volume.
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PMID:Effects of angiotensin II receptor blockade on hypoxia-induced right ventricular hypertrophy in rats. 940 68

This study was conducted to explore the mechanism of activation of transforming growth factor-beta1 (TGF-beta1) which is critical to its role in many physiological and pathological conditions. To date, almost all reports concerning TGF-beta1 activation delineated that release of mature TGF-beta1 from latency associated protein (LAP) is required for its activation. We report that latent TGF-beta1 (LTGF-beta1) released from TGF-beta1 genetically modified keratinocytes grown in the top chamber of a co-culture system functions as a fibrogenic factor through interaction with insulin-like growth factor-II/mannose-6-phosphate (IGF-II/M6P) receptors of human dermal fibroblasts grown in the lower chamber of this system. Following successful transduction, the pLin-LTGF-beta1 vector was amplified in PA31 7 packaging cells which possess viral structural proteins for vector in the presence of neomycin. Conditioned medium derived from packaging cells containing competent viral particles was then used to transduce either keratinocytes or fibroblasts grown in the upper chamber of a co-culture system, in which a 0.4 microm porous membrane separates the two chambers. In this way, LTGF-beta1 produced by transduced cells in the upper chamber is released and diffuses into the lower chambers where dermal fibroblasts are grown. Conditioned medium from the lower chamber was removed 3 days later and used to evaluate the latency and bioactivity of TGF-beta1 using enzyme-linked immunosorbent assay (ELISA) and mink lung (Mv1 Lu) epithelial growth inhibition assay. Cells were also harvested and used for RNA extraction. The results of these experiments showed that 1) the TGF-beta1-LAP complex, which was latent in traditionally used mink lung growth inhibition assay, directly modulated the expression of collagenase, type I, and type III collagen mRNA by dermal fibroblasts; 2) this stimulation was inhibited by M6P in a dose-dependent manner; 3) the TGF-beta1-LAP inhibits Mv1Lu epithelial cells only when this complex was incubated with cell membranes isolated from dermal fibroblasts; and 4) LTGF-beta1 activation seems to occur through a conformational alteration rather than by release of the mature TGF-beta1 from LAP in our co-cultured system. This conformational alteration seems to occur through the interaction of the TGF-beta1-LAP complex with the IGF-II/M6P receptors. Thus, the quantity of IGF-II/M6P receptors is important in cellular response to LTGF-beta1 in any physiological and pathological conditions.
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PMID:Insulin-like growth factor-II/mannose 6 phosphate receptors facilitate the matrix effects of latent transforming growth factor-beta1 released from genetically modified keratinocytes in a fibroblast/keratinocyte co-culture system. 1036 18

We have previously shown that insulin-like growth factor-1 (IGF-1) induces the expression of latent transforming growth factor beta 1 (LTGF-beta 1) through activation of c-fos and c-jun oncogenes. In this study we investigated whether IGF-1 induced latent TGF-beta 1 has autocrine effects on dermal fibroblasts and described a possible mechanism. Human dermal fibroblasts were treated with either vehicle, IGF-1 alone, or IGF-1 with either anti-TGF-beta 1 neutralizing antibody or mannose-6-phosphate (M6P) and levels of mRNAs for TGF-beta 1, collagenase and the pro alpha 1(I) chain of type I collagen were then evaluated by Northern analysis. Conditioned medium was also collected from treated and untreated cells and assayed for TGF-beta 1 protein by enzyme-linked immunosorbent assay. The results of the Northern analysis revealed a differential effect on the expression of the pro alpha 1(I) chain of type I collagen and collagenase in dermal fibroblasts: mRNA for the former being significantly increased in response to IGF-1 treatment while that for collagenase was markedly suppressed. These effects of IGF-1 were blocked to a significant extent by TGF-beta 1 neutralizing antibody at a concentration of 0.5-2.0 micrograms/ml. As the TGF-beta 1 induced by IGF-1 is inactive in the traditionally used mink lung epithelial cell growth inhibition assay, we explored the possible role of IGF-II/M6P receptors in facilitating these autocrine effects. The results showed that the greater than two-fold increase (201.9 +/- 38 vs 81.8 +/- 13, p < 0.05) in mRNA for the pro alpha 1(I) chain of type I collagen induced by IGF-1 was at least 60% inhibited by M6P in a time-dependent fashion. A direct correlation between the expression of TGF-beta 1 and the pro alpha 1(I) chain of type I collagen was found in response to either IGF-1 alone or IGF-1 with M6P. Treatment of cell cultures with TGF-beta 1 neutralizing antibody mimicked the effect of M6P. In contrast to the effects on expression of type I collagen, the level of collagenase mRNA was markedly reduced by IGF-1 alone and was restored by the administration of M6P. The levels of TGF-beta 1 in conditioned medium from treated and untreated cells showed a similar pattern to that of the mRNA detected by Northern analysis. These findings suggest that IGF-1 induces latent TGF-beta 1 and that the matrix-modulating autocrine effects of LTGF-beta 1 on dermal fibroblasts are facilitated by M6P/IGF-II receptors on these cells.
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PMID:Mannose-6-phosphate/IGF-II receptors mediate the effects of IGF-1-induced latent transforming growth factor beta 1 on expression of type I collagen and collagenase in dermal fibroblasts. 1070 75