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)

The aim of the present work was to develop a method for maintaining prepubertal human testicular cells in culture. Seven pairs of testes of boys who died of causes unrelated to endocrine or metabolic diseases were obtained at necropsy. Histology of the testes was normal. Testes were digested with collagenase and dispersed cells were seeded in multi-well dishes in the presence of 5% bovine fetal serum. After the first day, cells were cultured for five days in serum-free medium in the presence or absence of 918 pmol/l insulin. At the end of culture, microscopic examination showed healthy looking cells with characteristics compatible with pre-Sertoli cells; peritubular cells were identified by immunocytochemistry. In the presence of insulin, cells were able to secrete either testosterone or estradiol into the medium, as well as to reveal aromatase activity. In order to study the effect of the time elapsed between death and beginning of cultures, steroidogenic activity was related to this post mortem time. It was found that, in the presence of insulin, cells obtained from testes with less than 24 h of post mortem time secreted testosterone (64 +/- 7.2 pmol/10(6) cells.24 h, mean +/- SD) while cells obtained from testes with more than 24 h of post mortem time did not secrete testosterone. With long post mortem times, aromatase activity under insulin increased from non-detectable to 35 pmol/10(6) cells.24 h. Time course studies showed that cells with capacity to secrete testosterone increase this secretion gradually up to day 10 of culture, while those with detectable aromatase activity showed increments in this activity during the first week of culture.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Primary culture of prepubertal human testicular cells isolated from testes collected at necropsy. 151 25

Local production of estrogen in breast tissue may influence the growth of breast cancers. Peripheral conversion of C19 steroids to estrogens is catalyzed by the aromatase enzyme complex which is comprised of a specific form of cytochrome P450, aromatase cytochrome P450 (P450AROM) and the flavoprotein, NADPH-cytochrome P450 reductase. To evaluate P450AROM mRNA levels in breast tissue, a specific competitive polymerase chain reaction amplification procedure was devised. In this method, a rat P450AROM complementary RNA is coamplified as an internal standard in order to compare amplification reactions. The amplification products are recognized by hybridization with 32P-labeled oligonucleotides specific for each species. Densitometry is used to quantitate autoradiographs. Initial studies using RNA from whole breast tissue obtained from reduction mammoplasty revealed linearity of the relationship between the densitometer signal from the human amplification product and total RNA concentration. Breast tissue was then separated into a floating adipocyte fraction and a pelleted fraction containing the other cellular elements by collagenase digestion and centrifugation. Comparison of specific content of aromatase amplification product per unit weight of RNA extracted from adipocytes and pelleted cells revealed considerably higher levels in the RNA from the nonadipocyte fraction. Immunocytochemical characterization of this fraction revealed the presence of several cell types including macrophages, ductal epithelial cells, and endothelial cells, but primary cells of stromal origin.
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PMID:Determination of aromatase cytochrome P450 messenger ribonucleic acid in human breast tissue by competitive polymerase chain reaction amplification. 159 66

Immature female rats received either one injection of 2 mg diethylstilboestrol (DES)/rat subcutaneously and were killed 12 h later or received two injections of DES at 0 and 24 h and were killed at 24, 36 and 48 h after the initial injection. The ovarian follicles were released by enzymic digestion with collagenase and separated into those of small, medium and large diameter (less than 200 microns, 200-400 microns and greater than 400 microns) by filtration through graded Teflon sieves and granulosa cells were extracted from these follicles. The ovaries of immature rats treated with pregnant mares' serum gonadotrophin (PMSG) were used for comparative purposes. Incorporation of [3H]thymidine into granulosa cell DNA was augmented by DES and by PMSG. Small follicles were more strongly stimulated by DES at 12 h than those of other sizes, but rates increased significantly in medium and large follicles at 48 h. Aromatase activity in the DES-treated group was low at all times and in all follicles. Rates of oestrogen and progesterone production in response to 36 h of exposure to follicle-stimulating hormone (FSH) in vitro were significantly lower than in the PMSG-treated group. FSH-stimulated steroid production in the DES group at 36-48 h was lower, particularly in the medium follicles. A significant rise in serum FSH, luteinizing hormone (LH) and progesterone concentrations was noted only at 36 h after DES treatment, while serum and follicular fluid oestrogen values remained unchanged. When these changes were compared with those in PMSG-treated rats, there were obvious differences. The pattern of thymidine incorporation and aromatase activity differed with time and follicle size. Serum FSH and LH values were not affected by PMSG treatment, but serum and follicular fluid oestradiol values increased with time. The PMSG-treated animals ovulated in response to human chorionic gonadotrophin, but the DES-treated rats did not ovulate in spite of the presence of some large antral follicles in the ovaries. These findings show that initial exposure of follicles to high concentrations of oestrogen results in follicles which fail to respond to subsequent gonadotrophin surges and are thereby restricted in their ability to differentiate fully.
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PMID:Regulation of follicular development by diethylstilboestrol in ovaries of immature rats. 190 64

Adipose tissue is a major, nonglandular site for the aromatization of androgens to estrogens. In this tissue, the aromatase activity resides primarily in the stromal cells, and we have used cultures of stromal cells to study the effects of insulin and insulin-like growth factor I (IGF-I) on aromatase activity. Adipose tissue, obtained during indicated surgery, was digested with collagenase, and the stromal cells were isolated and cultured. Aromatase activity was determined by measuring the tritiated water (3H2O) in the medium after incubating stromal cells with [1 beta-3H]androstenedione. Insulin and IGF-I had no effect on the aromatase activity in cultured adipose stromal cells at concentrations of 10 to 1,000 microU/ml. However, insulin (100 to 1,000 microU/ml) and IGF-I (500 ng/ml) markedly attenuated the stimulatory effect of (Bu)2cAMP, but significantly augmented the dexamethasone-stimulated aromatase activity. The greater effects of IGF-I compared with the effect of insulin are compatible with both effects being mediated through the IGF-I compared with the effect of insulin are compatible with both effects being mediated through the IGF-I receptor. In addition, the effects of insulin in attenuating the aromatase activity in adipose tissue could potentiate its role in hyperandrogenic syndromes in women.
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PMID:Aromatase activity in human adipose tissue stromal cells: effect of growth factors. 196 38

A primary monolayer cell culture system was developed to investigate human corpus luteum (CL) function in vitro. Steroidogenic cells were isolated by collagenase dispersal and Percoll density-gradient fractionation from CLs enucleated at progressive stages of the luteal phase (tubal surgery patients). 'Pure' granulosa-lutein cells were aspirated from ovulatory follicles at mid-cycle (in-vitro fertilization patients). The steroidogenic capacity (progesterone/20 alpha-dihydroprogesterone biosynthesis and aromatase activity) of isolated luteal cells was assessed in relation to CL development. Basal luteal cell steroidogenesis was maximal at around the expected time of ovulation and declined with CL age during the luteal phase. Conversely, human chorionic gonadotrophin (hCG)-responsive steroidogenesis was initially undetectable but developed as the luteal phase progressed. These results show that luteal cell steroidogenesis becomes increasingly dependent upon gonadotrophic support with CL age. This is evidence that functional luteolysis in human ovaries (1) is pre-programmed to occur at the cellular level, (2) is initiated automatically at the time of ovulation and (3) is reversed at the time of CL 'rescue' in early pregnancy by the direct action of trophoblastic hCG on steroidogenic luteal cells. The culture system described should be of value in further defining the control of human CL form and function at the cellular level.
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PMID:Cellular basis of luteal steroidogenesis in the human ovary. 276 54

In the present study, a culture system of human placental cells was established to examine the role of estrogen and androgen in progesterone (P4) formation. Normal human placentae were obtained at term, and cells were dispersed in Hank's Balanced Salt Solution (5 ml/g tissue) containing 0.1% collagenase, 0.1% hyaluronidase, 0.01% deoxyribonuclease, and 1% fetal bovine serum for 2 h at 37 C. Dispersed placental cells (10(6) cells/ml) were placed in medium 199 with modified Earle's salts (pH 7.4) containing 10% fetal bovine serum, 12.5 mM HEPES buffer, 26 mM NaHCO3, and 40 micrograms/ml Gentamycin-SO4 and incubated for 72 h at 37 C and 5% CO2 in air to allow cell attachment. Medium was then changed (time zero), and P4 formation was studied thereafter. Culture of placental cells for 96 h resulted in linear increases in P4 and estradiol (E2) formation, indicating the maintenance of cell viability and steroidogenic function. Mean +/- SE P4 formation at 48 h was 246 +/- 16 pg/micrograms DNA. To assess the role of estrogen on P4 formation, placental cells were incubated for a period of 48 h with various amounts (10(-7)-10(-4)M) of the antiestrogen ethamoxytriphetol (MER-25), the aromatase inhibitor 4-hydroxyandrostenedione (4-OHA), and/or E2. Both MER-25 and 4-OHA resulted in a dose-dependent decline (P less than 0.01) in P4 formation (greater than 80% decline at 10(-4)M MER-25 or 4-OHA). The marked reduction in P4 formation caused by 4-OHA alone was reversed by concomitant addition of E2; however, E2 alone had no effect. To assess the role of androgens on P4 formation, cells were incubated for 48 h with increasing amounts (10(-7)-10(-4)M) of androstenedione, dehydroepiandrosterone (DHA), or dihydrotestosterone. Although the formation of E2 was enhanced by DHA, formation of P4 was not affected by the aromatizable androgens DHA or androstenedione or the nonaromatizable dihydrotestosterone. The decline in P4 formation by human placental cells in culture elicited by MER-25 or 4-OHA supports the hypothesis of a regulatory role for estrogen in placental P4 formation during human pregnancy. The lack of effect of exogenous estrogen suggests that the action of estrogen on P4 formation may be permissive.
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PMID:Regulation of progesterone formation by human placental cells in culture. 294 94

In mammalian ovaries, luteinizing hormone (LH) induces androgen biosynthesis by theca interna cells, whereas both follicle-stimulating hormone (FSH) and LH stimulate aromatase activity by granulosa cells. The joint action of these two types of cell and pituitary hormones forms the basis of a 2-cell, 2-gonadotropin hypothesis for biosynthesis of estrogen. We tested the synergism between these cell types using antisera against the estrogen precursors progesterone and testosterone. Ovaries were obtained from immature rats two days after a single injection of pregnant mare serum gonadotropin (PMSG). Granulosa cells were obtained by puncturing the follicles, and ovarian remnants were dissociated with collagenase to derive cells from the theca interstitium. Granulosa and theca interstitial cells were cultured alone or in combination for 20 h. Granulosa cells secreted negligible amounts of estrogen and testosterone, but contained high aromatase activity. Treatment with both FSH and human chorionic gonadotropin (hCG) increased production of progesterone in granulosa cells. In contrast, theca interstitial cells had negligible aromatase activity. Treatment with hCG, but not FSH, increased androgen production by theca interstitium; the hCG action was further augmented by the inclusion of exogenous progesterone. Furthermore, co-culture of gonadotropin-treated granulosa and theca interstitial cells resulted in substantial increases in estrogen production, indicating synergism between the two types of cell. The increases in estrogen production in the co-cultures were accompanied by decreases in progesterone content. To test the possibility that progesterone released by granulosa cells may serve as a substrate for production of androgen in theca cells, specific antiserum was used to adsorb progesterone present in the medium. Addition of the progesterone antibody inhibited gonadotropin-stimulated production of testosterone (39% decrease) and estrogen (64% decrease) by the combined cell cultures. The inhibitory effect on estrogen production could be reversed by the addition of progesterone (10(-6) M) or testosterone (10(-6) M) but not by the addition of a synthetic progestin, R5020. Since testosterone released from theca cells may serve as the substrate for aromatases in granulosa cells, specific testosterone antiserum was also used. Production of estrogens by the combined cell cultures was inhibited (78%) by the testosterone antiserum, but the inhibitory effect was completely reversed by exogenous testosterone or progesterone. Thus, synergistic interactions between granulosa and theca interstitial cells are important in effecting maximal estrogen biosynthesis.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Synergism between granulosa and theca-interstitial cells in estrogen biosynthesis by gonadotropin-treated rat ovaries: studies on the two-cell, two-gonadotropin hypothesis using steroid antisera. 309 Nov 3

FSH bioactivity was measured by means of FSH-dependent aromatase activity (conversion of androgen substrate to estradiol). Assay sensitivity was optimized by the use of immature (7-10 days old) rats as Sertoli cell donors, serum-free medium for incubation, phosphodiesterase inhibitor (methylisobutylxanthinine), serial dilution of FSH in medium containing 1% BSA, delayed addition of FSH for 72 h after cell plating, and 19-hydroxyandrostenedione (2.5 X 10(-6) M) as the aromatizable androgen substrate. The method consisted of subjecting the decapsulated immature rat testes to a 2-step collagenase dispersion, plating the cells in medium [Dulbecco's Modified Eagle's Medium-Ham's F-10 (1:1)] containing growth factors and methylisobutylxanthinine for 72 h, adding increasing doses of FSH to the standard curve or small volumes of serum to the test vials as well as 19-hydroxyandrostenedione for 24 h, and measuring estradiol by RIA in dilutions of the medium. Using NIAMDD human (h) FSH-2 as the bioassay standard, the useful range of the assay was 0.01-5.0 ng/ml. Specificity was determined by the addition of graded doses of hLH, hTSH, ACTH, hGH, hPRL, and hCG. The minor degree of FSH bioactivity observed in a few hormone preparations was accounted for by the degree of FSH contamination in them. Mean intra- and interassay coefficients of variation were 9% and 11%, and the index of precision was 0.049. This bioassay was used to determine the bioactive FSH content of pituitary extracts, tissue culture media, elutions from columns, and isoelectrically focused samples. More importantly, small quantities of human sera gave responses parallel to the standard curve in a minimum of two dilutions. The bio- to immunoreactive ratios, expressed as the mean +/- SEM (NIAMDD-hFSH-2), were 0.66 +/- 0.2 in boys (n = 6), 0.78 +/- 0.2 in pubertal girls (n = 6), 1.18 +/- 0.2 in men (n = 13), 1.24 +/- 0.1 in postmenopausal women (n = 30), 1.94 +/- 0.3 in the follicular phase (n = 19), 6.2 +/- 1.4 in the ovulatory phase (n = 19), and 1.6 +/- 0.4 in the luteal phase (n = 19) of the normal menstrual cycle. These results indicate that the bio- to immunoreactive hFSH ratio in the circulation, is dependent upon the hormonal milieu of the subject.
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PMID:An improved in vitro bioassay for follicle-stimulating hormone (FSH): suitable for measurement of FSH in unextracted human serum. 311 17

Development of a single follicle during the menstrual cycle is under control of hormones stimulating follicular maturation, ovulation and luteogenesis. Several factors intervene locally to prevent other follicles from developing at the same time as dominant follicle. These other follicles remain quiescent or evaluate to atresia. Atresia results from the action of several endocrine, paracrine and autocrine mechanisms which synergistically inhibit aromatase activity. The subsequent lack of estrogens reduces granulosa cell multiplication. The oocyte will not become fertilizable before the preovulatory peak of LH, after the resumption of meiosis and after reaching metaphase of the second meiotic division. Several factors are involved in the inhibition of spontaneous resumption of meiosis: cyclic nucleotides, sex steroids, somatostatin and oocyte maturation inhibitor(s) (OMI). Ovulation is related to breakdown of connective tissue synthesized by granulosa cells under the influence of FSH. Connective tissue lysis is dependent on proteolytic enzymes which are released and activated by FSH, LH and relaxin. A paracrine control could be involved in ovulation: LH induces the production of prostaglandin and relaxin by theca cells which, in turn, stimulate collagenase and proteoglycanase secretion by granulosa cells.
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PMID:Endocrine, paracrine and autocrine control of follicular development. 329 54

Development of a single follicle during the menstrual cycle is under control of hormones stimulating follicular maturation, ovulation and luteogenesis. Several factors intervene locally to avoid other follicles developing at the same time as the dominant follicle. These other follicles remain quiescent or go on to atresia. Atresia results from the action of several endocrine, paracrine and autocrine mechanisms which synergistically inhibit aromatase activity. The subsequent lack of oestrogens reduces granulosa cell multiplication. The oocyte will not become fertilizable before the preovulatory peak of LH, after the resumption of meiosis and after reaching the metaphase of the second meiotic division. Several factors are involved in this inhibition of spontaneous resumption of meiosis: cyclic nucleotides, sex steroids, somatostatin, oocyte maturation inhibitor(s) (OMI). Ovulation is related to breakdown of connective tissue synthesized by granulosa cells under the influence of FSH. Connective tissue lysis is dependent on proteolytic enzymes which are released and activated by FSH, LH and relaxin. A paracrine control could be involved in ovulation: LH induces the production of prostaglandin and relaxin by theca cells which, in turn, stimulate collagenase and proteoglycanase secretion by granulosa cells.
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PMID:[Endocrine, paracrine and autocrine mechanisms involved in follicular development]. 333 Jul 30


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