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 effects of different neurotransmitters were tested in vitro on a hypothalamic tissue, collagenase-digested isolated anterior pituitary and Leydig cell suspension system by measuring the testosterone production of the Leydig cells. Neurotransmitters were used in concentrations of 0.25, 1.0, 2.5, 5.0, and 10.0 micrograms/ml incubation medium. Dopamine in doses of 1.0, 2.5, and 5.0 micrograms/ml increased the hypothalamic tissue-induced pituitary-testis activation, while it had no direct effect on pituitary and Leydig cells. Noradrenaline in the concentration range 2.5--10.0 micrograms/ml decreased the luteinizing-hormone-releasing-hormone (LHRH) sensitivity of the pituitary cells. 5.0 and 10.0 micrograms/ml 5-hydroxytryptamine decreased the testosterone production and the hCG sensitivity of the isolated Leydig cells. Carbamylcholine and pilocarpine had no action on the in vitro system at the different levels studied.
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PMID:Study of the effects of neurotransmitters on the hypothalamus-pituitary-testis function in in vitro cell suspension system. 4 66

An LH-responsive Leydig cell preparation (containing 6+/-2% Leydig cells) was obtained by collagenase treatment of rat testis. Centrifugation of this cell preparation through a 13% Ficoll solution for 10 min at 1500 g resulted in a four times purification of the Leydig cells, with a concomitant increases in steroidogenic activity. Addition of 0-2% albumin to the 13% Ficoll solution, adjusted to 280 mosmol/l, resulted in a further twofold purification of the Leydig cells paralleled by a twofold increase in steroidogenic activity. Centrifugation of these Ficoll-albumin-purified Leydig cells through a 6% dextran solution for 2 min at 100 g resulted in a further 1-7 times purification of the Leydig cells. A combination of the two centrifugation steps resulted in a 12-5 times purification of Leydig cells compared with the original crude cell suspension, while an increase in steroidogenic activity of 22-5 times was obtained. This final cell preparation contained 59 +/- 17% Leydig cells (mean +/- S.D., n = 6). The recovery of Leydig cells was 29%. Collagenase treatment of testes deficient in spermatogenesis resulted in a cell preparation with the same steroidogenic activity as Ficoll-purified cells from normal testes. Centrifugation of these cells through a 13% Ficoll solution gave only a limited increase in the steroidogenic activity. Isopycnic centrifugation of the crude cell preparation on a discontinous Ficoll metrizoate gradient resulted in two discrete peaks of Leydig cells, one peak at a density of 1-039-1-055 g/ml and one at a density of 1-068-1-088 g/ml. Both types of cells produced testosterone. In the presence of LH, cyclic AMP production in both types of Leydig cells increased, but testosterone production was only increased by LH in the "denser" Leydig cells and not in the "light" Leydig cells. No difference in sensitivity to LH could be observed between the Leydig cell preparations of different purity. Using a 60 min pre-incubation period the highest testosterone response was obtained with 100-1000 ng LH/ml. The same maximum testosterone response was obtained with 10-100 ng LH/ml when the pre-incubation period was omitted.
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PMID:Purification and characterization of Leydig cells from rat testes. 18 9

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.
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PMID:Effect of prostaglandins on hypothalamic-pituitary-testicular function in vitro. 39 65

Using a modification of the collagenase dispersion method of Dufau et al., we examined changes in DNA synthesis produced by estrogens in the interstitial cells of mice that develop malignant Leydig cell tumors after prolonged estrogen administration. Previous work in cryptorchid mice indicated that during continuous estrogen administration [3H]thymidine incorporation into DNA rises to a maximum in 3 to 4 days and then falls to approximately base levels within 2 to 3 weeks. This was confirmed both in Leydig cell concentrates of estrogen-treated mice after either injection with [3H]thymidine or incubation with [3H]thymidine in vitro. This DNA synthesis was blocked by hydroxyurea. DNA synthesis in cells of estrogen-treated BALB/c mice of the Huseby substrain, which have a high incidence of Leydig cell tumors, was 5 to 11 times that in untreated controls. Cells from estrogen-treated C3H/Bi mice, which have a low incidence of Leydig cell tumors, showed only a 2- to 3-fold increase. In the Huseby substrain the rise of DNA synthesis is a peak and subsequent recession were paralleled by a rise and fall in DNA polymerase alpha activity. DNA polymerase beta did not show this variation. In C3H/Bi mice, neither polymerase showed significant change. The evidence suggests that the early estrogen-stimulated DNA synthesis is probably replicative and is associated with increased DNA polymerase alpha activity.
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PMID:DNA synthesis and DNA polymerase activity in Leydig cells of diethylstilbestrol-stimulated mouse testes. 62 Apr 11

To examine whether immature rat Sertoli cells in culture secrete a factor(s) which stimulates testosterone production by mature mouse Leydig cells, Sertoli cell-enriched cultures were prepared from 3-week-old male rats with trypsin and collagenase. Sertoli cells were plated at an initial density of 3-5 x 10(6) cells/35 mm well and cultured in 3 ml serum free media supplemented with insulin (10 micrograms/ml). Sertoli cell culture medium (SCCM) collected every 3rd day was added to Leydig cells (10(6) cells in 1 ml of MEM with 2% steroid-free FCS) prepared from 10-week-old mice by mechanical separation and incubated for 3 h at 34 degrees C. Secreted testosterone was determined by RIA. SCCM 15 times concentrated by Amicon YM10 membrane demonstrated a dose-dependent stimulation of testosterone production, whereas there was no effect on testosterone secretion when Leydig cells were maximally stimulated by LH. Leydig cell stimulating activity was retained by both a dialysis membrane with a pore size of 24 A and an ultrafiltration membrane with a molecular weight cut-off of 10 kDa. However, activity was reduced by heating at 60 degrees C for 30 min and almost lost after incubation with 0.1% trypsin for 1 h at 37 degrees C. This activity was not retained by means of a Con A-Agarose column and was demonstrated only in break-through fractions. HPLC gel filtration of a 15 times concentrated SCCM preparation on a TSK gel G3000SW revealed Leydig cell-stimulating activity at approximately 13 kDa.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:A partial characterization of a Sertoli cell-secreted protein stimulating Leydig cell testosterone production. 139 52

A method involving centrifugal elutriation followed by density gradient centrifugation and incubation with a macrophage monoclonal antibody has been investigated to separate and characterize Leydig cells and macrophages from adult rat testes. After dispersion of the testes with collagenase, the isolated interstitial cells were found to contain 18% Leydig cells and 12% macrophages. These cells were then separated by centrifugal elutriation into eight fractions (F1-F8) (9 to 74 ml/min at 386 g). Each of these fractions was then further purified by density gradient centrifugation on 0-90% Percoll gradients. After centrifugal elutriation, the macrophages were mainly eluted in the first three fractions (F1-F3), whereas the Leydig cell percentage increased in each fraction with increasing flow rate. After further purification of each fraction on Percoll gradients, high percentages of macrophages (11-20%) were found in fractions F1-F3 (average density 1.045 g/ml), containing 11-37% Leydig cells. Less than 3% of the cells in fraction F4-F8 (average density 1.075 g/ml) were macrophages and more than 95% were Leydig cells. Heterogeneity of Leydig cells with respect to sedimentation velocities and function was found. Leydig cells from elutriated- and Percoll-purified fractions F4-F8 were heterogeneous with respect to testosterone and cyclic AMP (cAMP) production but showed a similar binding capacity for 125I-labelled human chorionic gonadotrophin. Leydig cells with the highest sedimentation velocity (35.7 mm/h.g) from fractions F7 and F8 were approximately twofold more responsive to LH (3.3 nmol/l) with respect to testosterone and cAMP production compared with Leydig cells with the lowest sedimentation velocity (20.7 mm/h.g).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Separation and characterization of Leydig cells and macrophages from rat testes. 165 79

This study was designed to determine the effects of 17 beta-estradiol (E2) on Leydig cell development in the rat. Mature (60 to 65 days old) male rats received a single intraperitoneal injection of ethane dimethylsulfonate (EDS, 100 mg/kg body weight); untreated rats served as controls. In one series of experiments, groups of EDS-treated rats also received daily injections of either E2 (25 micrograms/100 g body weight), human chorionic gonadotropin (hCG, 20 IU/day), a combination of the two, or vehicle only (EDS controls). Animals were killed on days 2, 4, 10, 16, 24, 30, and 36 after EDS treatment. In another series of experiments, groups of EDS-treated rats received daily injections of hCG and E2 during days 0 through 5, 5 through 30, or 16 through 30 after EDS treatment, and were killed on day 30. In both series of experiments, the steroidogenic capacity and hCG binding capacity of the Leydig cells were examined in short-term in vitro incubations using collagenase-dispersed interstitial cells. Testes were also prepared and examined histologically by light and electron microscopy. E2 treatment of animals during the initial 5 days after EDS administration had no effect on the regeneration of interstitial cells and Leydig cells. Treatment with E2 during days 5 to 30 post-EDS blocked the regeneration of Leydig cells and thereby significantly reduced the increase in interstitial cell numbers. Finally, when E2 treatment was delayed until 16 days post-EDS, there was no significant reduction in the regeneration of interstitial or Leydig cells. These data suggest that an important developmental process that is necessary for Leydig cell regeneration occurs between days 5 and 16 post-EDS.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:17 beta-estradiol inhibition of Leydig cell regeneration in the ethane dimethylsulfonate-treated mature rat. 166 73

Pro-opiomelanocortin (POMC) gene expression and POMC peptides have been demonstrated in the Leydig cells of the testis, although selective removal of the Leydig cells with the cytotoxic drug ethane dimethane sulfonate did not significantly reduce levels of testicular POMC mRNA or peptides in adult rats. Since macrophages in the rat spleen synthesize POMC peptides, we investigated whether isolated macrophages from the adult rat testis may be an additional source of POMC-derived peptides. Testicular macrophages were isolated by collagenase treatment of adult rat testes and adherence to siliconized glass coverslips; the biological, cytochemical and immunological characteristics of the attached cells were compared with those of Leydig cells purified by Percoll gradient centrifugation. Macrophages in the cell preparations were identified by positive esterase cytochemical staining, latex bead ingestion, and immunocytochemical staining with ED2 (a macrophage-specific monoclonal antibody), and an absence of 3 beta-hydroxysteroid dehydrogenase cytochemical staining. Leydig cells in the purified preparations were positive for 3 beta-hydroxysteroid dehydrogenase and esterase staining but negative with ED2, and were not phagocytic. Based on these criteria, the purities of the macrophage and Leydig cell preparations employed in this study were estimated to be 87 +/- 4% and 91 +/- 3%, respectively. Cytoplasmic beta-endorphin (beta EP) immunoreactivity (ir) was present in 62 +/- 9% of cells in the purified Leydig cell preparations--confirming these cells as a source of POMC-derived peptides. In addition, ir-beta EP and ir-ACTH were localized to the cytoplasm of a similar proportion of cells (beta EP, 62.5 +/- 5%; ACTH, 64 +/- 5%) in macrophage preparations.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Localization of immunoreactive beta-endorphin and adrenocorticotropic hormone and pro-opiomelanocortin mRNA to rat testicular interstitial tissue macrophages. 166 44

Mature (60-65 day old) male Sprague-Dawley rats received a single intraperitoneal injection of ethylene dimethane sulphonate (EDS; 100 mg/kg) and were subsequently killed at various times from day 2 to day 40 post-treatment. Testes were removed from these animals and age-matched controls and utilized either for light and electron microscopical analyses or for in-vitro assessment of Leydig cell function. Interstitial cells were prepared by collagenase digestion and used to measure 125I-labelled human chorionic gonadotrophin (hCG) binding capacity and androgen production in the presence or absence of hCG or dibutyryl cyclic AMP (dbcAMP). At day 2 after EDS treatment, 125I-labelled hCG binding capacity was reduced to 10% of control values, while the production of testosterone and 5 alpha-androstane-3 alpha, 17 beta-diol (adiol) were non-detectable. Histological observations confirmed the lack of identifiable Leydig cells at day 2-16 after EDS treatment. Between days 24 and 40 post-treatment, Leydig cell regeneration occurred, as indicated by a rise in 125I-labelled hCG binding capacity, increased androgen production and the presence of histologically identifiable Leydig cells. A pattern of adiol production similar to that seen in the immature rat during Leydig cell development was observed with peak synthesis occurring at day 30 post-treatment. Adiol production fell to barely detectable levels by day 36 and remained low at day 40. It is concluded that the steroidogenic pattern of regenerating Leydig cells in the EDS-treated animal is similar to that of developing Leydig cells in the immature animal.
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PMID:Testosterone and androstanediol production by regenerating Leydig cells in the ethylene dimethane sulphonate-treated mature rat. 215 79

Macrophages were identified in the intertubular tissue of the rat testis by loading animals with a particulate vital dye (trypan blue or India ink) and by localizing immunocytochemically a macrophage membrane antigen (MRC W3/25). Leydig cells were identified by the histochemical staining reaction for 3 beta-hydroxysteroid dehydrogenase activity and by a monoclonal antibody. Macrophages were scattered in the interstitial tissue closely attached to and mixed with the Leydig cells. They were never found in the seminiferous tubules. The macrophages comprised about 25% of all the cells in the interstitium. Double staining with a vital dye and a marker antibody showed that all the phagocytosing cells were macrophages and that the Leydig cells did not take up vital dyes. Double staining for the demonstration of the 3 beta-hydroxysteroid dehydrogenase activity and the macrophage antigen likewise revealed two distinctly different cell populations. Crude Leydig cell preparations obtained by collagenase treatment of the testis contained macrophages (12-14%). Macrophages were present throughout the postnatal prepuberal development of the testis. Their density was increased in the cryptorchid and irradiated testis.
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PMID:Macrophages in the interstitial tissue of the rat testis. 241 75


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