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)

This study examines the influence of ovariectomy and administration of a pharmacologic dose of estradiol on amylase release from isolated-dispersed rat pancreatic acini and cholecystokinin receptors on rat acinar cell membranes. Rats were sham ovariectomized (intact) or ovariectomized (Ovx) and 21 day timed release pellets containing either estradiol (2.5 mg) or vehicle, were implanted subcutaneously. Eighteen days later, pancreatic acini were isolated from rats by collagenase digestion and differential centrifugation. Total cellular amylase, basal and cholecystokinin octapeptide (CCK8) stimulated amylase release and CCK membrane receptors were measured. Acini isolated from estradiol treated Ovx rats had significantly greater total cellular amylase, compared to acini isolated from either intact or Ovx rats. The amplitude of both total stimulated amylase release and percent total stimulated amylase release were significantly greater for acini isolated from vehicle treated Ovx rats, than acini isolated from either intact or estradiol treated Ovx rats. The magnitude of percent total amylase release of acini isolated from estradiol treated Ovx rats was significantly lower than that of acini isolated from intact rats. Cholecystokinin receptor concentration was significantly greater on membranes prepared from vehicle treated Ovx rats, compared to membranes prepared from either intact or estradiol treated Ovx rats. These data indicate that ovariectomy is associated with increased responsiveness of pancreatic acini to CCK stimulation, while chronic estradiol treatment of ovariectomized rats is associated with increased total cellular amylase and decreased acinar cell responsiveness to CCK8. Estrogen mediated alterations in acinar cell amylase content and amylase release may play a role in estrogen related pancreatitis.
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PMID:Estrogens influence cholecystokinin stimulated pancreatic amylase release and acinar cell membrane cholecystokinin receptors in rat. 170 70

The objective of this study was to determine whether DNA synthesis induced in the livers of female rats treated with ethinyl estradiol (EE) was due to direct effects of this synthetic estrogen on hepatocytes. Hepatocytes, obtained by collagenase perfusion from female Lewis rats, were cultured in serum-free medium containing low or no phenol red and supplemented with insulin, transferrin, and selenium. When present at 10-15 microM for the initial 30 h of culture, EE caused a subsequent 2-2.7-fold increase in hepatocyte DNA synthesis. Pretreatment of the hepatocytes with EE during the first 30 h of culture caused an EE concentration-dependent enhancement of their subsequent DNA synthetic response to epidermal growth factor (EGF). Pretreatment with EE shifted the EGF dose-response curve, causing a dramatic enhancement of the response to EGF beginning at 2 ng EGF/ml. The response to a saturating (25 ng/ml) dose of EGF was also greatly enhanced. Determination of the effect of EE on hepatocyte surface EGF receptors revealed that the increased responsiveness of DNA synthesis to EGF was accompanied by a twofold increase in EGF receptor number per cell. These results indicate that EE has direct, growth-related effects on hepatocytes which may contribute to liver growth induced in vivo by this tumor promoter.
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PMID:Effects of the liver tumor promoter ethinyl estradiol on epidermal growth factor-induced DNA synthesis and epidermal growth factor receptor levels in cultured rat hepatocytes. 278 53

Estrogen production in vitro was compared for Leydig cells from cryptorchid and scrotal testes in boars and stallions. Animals with natural and experimental cryptorchidism were used. Purified Leydig cells were prepared from testes of mature animals by collagenase treatment and Percoll density gradients. After incubation for 3 hours (1 X 10(6) cells), estrone sulfate and estrone in the media were measured by direct radioimmunoassay. Androstenedione and testosterone in media extracts also were determined. Cells from the abdominal testis of unilateral cryptorchid boars and stallions showed impaired estrogen production compared with that of the contralateral scrotal testis. Surgical translocation of the scrotal testis to the abdominal cavity in four unilaterally cryptorchid, prepubertal boars did not result in a reduced capacity for estrogen secretion by Leydig cells examined after puberty. Cells from the naturally retained testis in each of these four animals produced practically no estrogen. In a naturally bilateral cryptorchid stallion, there was a high rate of estrogen secretion by both testes. It was concluded that the scrotal testis of a unilaterally cryptorchid animal exerts a suppressive influence on estrogen formation by the abdominal testis.
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PMID:Impaired estrogen production by Leydig cells of the naturally retained testis in unilaterally cryptorchid boars and stallions. 287 46

Previous studies from this laboratory have documented a progressive decline in basal and ACTH-stimulated corticosterone production in isolated adrenocortical cells as rats age. In the current study we examined the possibility that the aging process exerts this effect by interfering with the mechanism(s) by which cholesterol is processed and/or synthesized by the adrenal gland. Freshly excised adrenals from 2-, 5-, 12-, and 18-month-old rats were used for the measurement of cholesteryl ester, free cholesterol, cholesteryl esterases, and acyl co-enzyme A (CoA)-cholesterol acyltransferase activities as well as key enzymes involved in cholesterol biosynthesis. The results showed that cholesteryl ester content increased in a linear manner with advancing age, while neutral cholesteryl esterase activity decreased steadily until at 18 months of age it reached 40% that of 2-month-old control rats. In contrast, lysosomal acid cholesteryl esterase did not change with age, and acyl CoA: Cholesterol acyltransferase showed only a 33% decrease at 12 months of age. The activity of 3-hydroxy-3-methylglutaryl CoA reductase, the rate-limiting enzyme in cholesterol biosynthesis, decreased steadily with advancing age, and at 18 months of age, activity was only half of that in 2-month-old control rats. In contrast, the activities of other enzymes involved in the de novo synthesis of cholesterol, namely acetoacetyl CoA thiolase and HMG CoA synthase, were similar in 2- and 12-month-old rats, while mevalonate kinase activity was significantly lower in the 12-month-old rats. After depletion of plasma lipoprotein cholesterol by 4-aminopyrazolo-[3,4-d]pyrimidine, the intraadrenal cholesteryl ester content in young and aged animals fell significantly. Furthermore, such treatment enhanced the activities of all of the cholesterol de novo synthetic enzymes examined. In addition, HMG CoA synthase and HMG CoA reductase activities rose to much greater levels in both young and old rats compared to acetoacetyl CoA thiolase and mevalonate kinase. Finally, markedly higher activities of HMG CoA reductase were observed in 12- and 18-month-old rats after 4-aminopyrazolo-[3,4-d]pyrimidine treatment. Similar results were seen using 17 alpha-ethinyl estradiol to deplete cholesterol and adrenal sterol ester stores. The metabolism of endogenous cholesterol and exogenous hydroxysterols (which bypass the cAMP-dependent transport of endogenous cholesterol to mitochondrial side-chain cleavage enzyme complex) to corticosterone by collagenase-dispersed adrenocortical cells isolated from rats of various ages were also studied.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Effects of aging on cholesterol content and cholesterol-metabolizing enzymes in the rat adrenal gland. 288 78

Flow cytometric determination of tumor ploidy and S-phase fraction following collagenase dissociation and thymidine labeling was performed on 75 consecutive breast cancers. Estrogen and progesterone receptor levels and routine histologic examination also were obtained on each tumor. Cell viability following collagenase dissociation varied from 13 to 95% with a mean of 71%. Thirty-six tumors were diploid, four tetraploid, and four hypertetraploid, and the remainder had DNA indices between 1.1 and 1.9. There was no significant correlation between tumor ploidy and tumor size or estrogen receptor positivity or negativity. The percentage of cells in S-phase varied from 1.2 to 20.0% with a mean of 6.0% utilizing a rectilinear model for histogram analysis that integrated a 10-contiguous channel sample containing the lowest number of cells in S-phase (S-pFL). The mean S-pFL of diploid carcinomas (3.43%) was significantly lower than that of hyperdiploid carcinomas (8.38%). There was good correlation between S-phase fraction determined by thymidine-labeling index (TLI) and S-pFL (r = 0.772, p = 0.0001). S-pFL predicted whether a tumor would be above or below median TLI with an accuracy of 90.5%. Estrogen receptor-negative cancers tended to have higher TLIs and S-pFLs than estrogen receptor-positive cancers; however, there was no correlation between progesterone receptor positivity or negativity and TLI and S-pFL.
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PMID:A comparison of human breast cancer cell kinetics measured by flow cytometry and thymidine labeling. 298 50

The present study determined if the decline in placental progesterone (P4) production that results from administration of the antiestrogen ethamoxytriphetol (MER-25) to pregnant baboons results from a change in placental low density lipoprotein (LDL) uptake and/or degradation. Pregnant baboons (Papio anubis) were untreated (n = 10) or received MER-25 (25 mg/kg BW, orally; n = 10) daily on days 140-170 of gestation (term, 184 days). Placentas were removed by cesarean section on day 170 of gestation, and villous tissue was dispersed with 0.1% collagenase at 37 C for 40 min. Placental cells (10(6)) were incubated in medium 199 (pH 7.2) for 12 h at 37 C with increasing amounts (5-100 micrograms) of [125I]LDL, with or without a 100-fold excess of unlabeled baboon LDL. Mean (+/- SE) peripheral serum P4 concentrations on days 140-170 of gestation were 51% lower (P less than 0.01) in MER-25-treated (5.7 +/- 0.3 ng/ml) than in untreated (11.6 +/- 0.5 ng/ml) baboons. The uptake of LDL was 56% lower (P less than 0.01) in placental cells from antiestrogen-treated (6.3 +/- 1.6 ng/micrograms cell protein) than in those from untreated (14.4 +/- 1.9 ng/micrograms cell protein) baboons. The dissociation constants for placental LDL uptake, as assessed by Scatchard analysis, however, were similar in untreated (0.80 microgram/ml) and MER-25-treated (0.76 microgram/ml) animals. The amount of [125I]LDL concomitantly degraded by cells from baboons that received MER-25 was 54% of that degraded by cells from untreated controls. The relative decline in LDL degradation by cells of antiestrogen-treated baboons was proportionate to the decline in overall LDL uptake. The results indicate, therefore, that antiestrogen treatment decreased the amount of placental LDL uptake, but did not change the affinity for the lipoprotein. We suggest that the decline in placental P4 production elicited in pregnant baboons by antiestrogen results, at least in part, from subnormal LDL uptake. We propose that one of the mechanisms by which estrogen regulates the biosynthesis of P4 by the placenta during baboon pregnancy is by increasing receptor-mediated placental cell uptake of cholesterol in the form of LDL. Estrogen, therefore, may regulate LDL uptake by the placenta and thus the availability of cholesterol for P4 biosynthesis via the LDL pathway.
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PMID:Effect of the antiestrogen ethamoxytriphetol (MER-25) on placental low density lipoprotein uptake and degradation in baboons. 335 75

Estrogen-dependent stimulation of progesterone receptor (PgR) concentration or cell proliferation of normal mammary epithelial cells in vitro has been shown to be associated with the presence of mammary fibroblasts. To investigate further the nature of fibroblast influence on epithelial cells, Percoll-purified epithelial cells from collagenase-dissociated mammary glands of mid-pregnant BALB/c mice were co-cultured with mammary fibroblasts that were either untreated, irradiated, or glutaraldehyde-killed or with fibroblast-conditioned medium. Epithelial cells were then assayed for either estrogen-dependent stimulation of PgR by measuring specific [3H]R5020 binding or for estrogen-dependent stimulation of DNA synthesis by [3H]thymidine autoradiography. The results demonstrate that stimulation of PgR does not require the presence of live fibroblasts; either glutaraldehyde-killed fibroblasts or conditioned medium was effective. Pretreatment of culture dishes with type I collagen was equally effective, indicating that fibroblasts may promote the PgR response via a substratum effect. In distinct contrast, estrogen-dependent stimulation of DNA synthesis occurred only when live fibroblasts were present in high numbers and/or in direct contact with epithelial cells. Furthermore, under these latter conditions, epithelial cells also promoted estrogen-dependent stimulation of fibroblast DNA synthesis. Differences in both epithelial and fibroblast cell morphologies were also observed under co-culture conditions, which suggested that cell-cell communication or another interactive phenomenon takes place and is bidirectional. Thus there appear to be at least two different mechanisms by which fibroblasts can influence two specific responses of epithelial cells to estrogen. The present results demonstrate that the specific nature of epithelial-stromal interactions can determine and modulate epithelial cell responses to estrogen and may reflect in vivo regulatory processes affecting normal and neoplastic mammary cells.
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PMID:Mammary fibroblast influence on normal mouse mammary epithelial cell responses to estrogen in vitro. 394 Jan 97

MCF-7 cells, a human breast carcinoma line, forms tumors when injected into athymic nude mice. These tumors are able to metastasize to lungs, liver and spleen. 17 beta-estradiol treatment increases both the growth rate and frequency of metastases. Castration or diabetes prevents metastasis formation, but treatment with estrogen or insulin restores the metastasizing capacity. MCF-7 cells secrete into the culture media collagenases able to lyse types I and IV collagens. Estrogen or insulin addition to the culture enhances collagenase production. Attention is called to the coexistence of enhancement in collagenase production and metastasis formation.
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PMID:Formation of metastasis by human breast carcinoma cells (MCF-7) in nude mice. 645 Jun 36

A new hydrolase activity has been identified by its capability of cleaving t-boc-Ala-Ala-Pro-Ala-AMC, the released 7-amino-4-methylcoumarin (AMC) being quantified fluorometrically. The activity in the 28,000 X g supernatant fraction of homogenates of weanling mouse uterus was about one fifth that of the adult mouse. The administration of estradiol to the weanling mouse caused a prompt increase in uterine hydrolase, the response being biphasic with peaks at 2 and 6 h. Stimulation was dose responsive and effectively blocked by cycloheximide and puromycin. Estrogen stimulation of hydrolase activity was also observed in the kidney (one fourth that of in the uterus), but not in the heart or liver. Progesterone and testosterone were poor stimulators, but estriol was as effective as estradiol. According to its elution profile in gel filtration, a molecular weight for the hydrolase of about 60,000 is suggested. Inhibition studies in vitro with crude enzyme preparations indicate a serine protease with a SH group essential for maximal activity. The natural substrate for the hydrolase has not been elucidated. It does not solubilize [3H]elastin, and the properties seem to eliminate plasminogen or latent collagenase as possible substrates.
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PMID:A new hormone-response hydrolase activity in the mouse uterus. 700 May

Single cells from a patient (B. E., 65 years) have been isolated by collagenase treatment and cultivated in vitro. The human tumour of the mammary gland showed predominantly simple undifferentiated and also tubular structures. The 5th in vitro passage of these cells was characterized by DNA-distribution pattern, cell doubling time, chromosome number, ultrastructure, hormone and drug sensitivity. Cells of the 5th in vitro passage were i.p. transplanted into nude mice. The characteristics of in vitro cultivated cells (5th in vitro passage) were compared with both ascitic cells (1703/A) and cells of solid tumour material (1703/S) grown in nude mice for several passages (0, 10, 21). DNA-distribution patterns, chromosome numbers and cell doubling times are in good correlation. The number of polyploid cells is increased in ascitic cells. These malignant cells are best able to proliferate in vitro after transplantation into nude mice. Ultrastructure examination of the 21st passage has shown similarity between cultured cells, ascitic cells and cells of solid tumour material grown in nude mice. Virus particles could be observed in cells of solid only. Estrogen binding could be observed in the original tumour material only. All other cell or tissue preparations contained no receptors. Drug sensitivity was changed in the case of Vinblastin, Daunoblastin and Sarkolysin treatment of cells of solid tumour material more than in ascitic cells grown in nude mice. The environment dependence of cells and biological differences between in vivo-in vitro tumours and human neoplasms has to be taken into account when using cells as in vivo or in vitro model systems in experimental and clinical cancer research.
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PMID:Biological characterization of cells derived from a human breast carcinoma. I. Some characteristics of cells cultivated in vitro prior to and after transplantation into nude mice. 708 29


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