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 purpose of this study was to evaluate the effects of GnRH-analog (Leuprolide acetate, LA) administration on follicular luteinization in equine chorionic gonadotropin plus human chorionic gonadotropin (eCG + hCG)-superovulated prepubertal treated rats. Results indicate that LA treatment decreases circulating levels of progesterone (P) and P accumulation in collagenase-dispersed ovarian cell cultures, though estradiol (E2) production is increased. These data suggest that cells from the LA group may be less luteinized following gonadotropin treatment. Studies performed on histological ovarian sections after different times of eCG administration showed that LA injections produce lower amounts of corpora lutea and antral follicles, and a greater number of atretic and preantral follicles. The basal and LH-stimulated P and progestagen accumulations are decreased in incubations of corpora lutea isolated from the LA group. In addition, the mitochondrial cholesterol side-chain cleavage (P450SCC) levels in corpora lutea from LA-treated rats are reduced, indicating that the decrease in P production observed is due in part to an alteration in the steroidogenic luteal capability. Immunocytochemical localization of nuclei exhibiting DNA fragmentation by the technique of terminal deoxynucleotidyl transferase end-labeling showed that LA treatment causes an increase in the number of apoptotic cells in preantral and antral follicles at all times studied (1, 2, 4, or 7 days of LA administration). A similar effect, though less pronounced, was observed in corpora lutea. It is concluded that LA treatment produces a failure in the steroidogenic luteal capability and an increase of apoptotic mechanisms in the ovary, producing as a consequence an interference in the follicular recruitment, growth, and luteinization induced by gonadotropins.
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PMID:Regulation of follicular luteinization by a gonadotropin-releasing hormone agonist: relationship between steroidogenesis and apoptosis. 977 49

Evodiamine, a bioactive component isolated from the Chinese medicine Wu-chu-yu, exhibits vasodilative and antianoxic action. Although evodiamine indeed has many biological effects, its effects on the endocrine system are not clear. The present study explored the effects of evodiamine on testosterone secretion in vitro. Rat collagenase-dispersed testicular interstitial cells (TICs) were incubated with evodiamine (0 to 10(-4) mol/L) in the presence or absence of human chorionic gonadotropin (hCG), forskolin, 8-bromo-adenosine 3':5'-cyclic monophosphate (8-Br-cAMP), or steroidogenic precursors (including 25-hydroxycholesterol, pregnenolone, progesterone, 17alpha-hydroxyprogesterone, and androstenedione) at 34 degrees C for 1 hour. The testosterone concentration in the media samples was measured by radioimmunoassay. Evodiamine 10(-4) mol/L was effective to reduce both basal and hCG-stimulated testosterone secretion in rat TICs after 1, 2, or 4 hours of incubation. The stimulatory effect of forskolin on testosterone release in TICs was prevented by administration of evodiamine. Evodiamine 10(-4) mol/L also decreased 8-Br-cAMP- and androstenedione-stimulated testosterone secretion. These results suggest that evodiamine reduces testosterone secretion in rat TICs via a mechanism involving reduced activity of cAMP-related pathways and 17beta-hydroxysteroid dehydrogenase (17beta-HSD).
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PMID:Effects of evodiamine on the secretion of testosterone in rat testicular interstitial cells. 1059 84

Degelification of highly viscous alpaca semen was attempted using two enzymes: trypsin and collagenase. Dilution effect on artificial insemination was determined in alpacas. Semen from 4 male alpacas was collected, degelified, diluted, and inseminated into 80 female alpacas. Degelification was achieved adding trypsin and collagenase enzymes to fresh semen samples. Semen was diluted with egg-yolk glucose citrate to give concentrations of 4, 8, and 12 million spermatozoa/mL. Females were induced to ovulate with human chorionic gonadotropin and then inseminated deep into the uterine horns. Analysis of variance was used to determine differences in the effect of trypsin and collagenase on sperm acrosome and on motility and live spermatozoa. The chi-square test was used to determine differences in pregnancy of artificially inseminated females. Semen was degelified with different concentrations of trypsin and collagenase. There were differences (p < .05) in the pregnancy rate of female alpacas inseminated with 4 million (53.3%), 8 million (66.7%), and 12 million sperm/mL (61.5%). Alpaca semen may be degelified using trypsin and/or collagenase. It seems that 8 million sperm/mL is adequate for artificial insemination in alpacas.
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PMID:Degelification of alpaca semen and the effect of dilution rates on artificial insemination outcome. 1062 9

Gap junctions are intercellular protein channels which provide a pathway for the exchange of ions and small molecules. This exchange of materials allows metabolic coupling of cells. Gap junction channels are made up of connexins, integral membrane proteins encoded by a multigene family. Rat testes contain mRNAs for at least five different connexins: Cx26, Cx32, Cx33, Cx37 and Cx43. Immunocytochemical studies have shown that Cx43 assembles gap junctions between Leydig cells. The present study investigated the expression and regulation of the Cx43 gene in rat Leydig cells. Purified Leydig cells were obtained from 40- to 80-day-old Sprague-Dawley rats using a combination of arterial perfusion, collagenase digestion, centrifugal elutriation and Percoll gradient centrifugation. Leydig cells from 20- and 30-day-old rats were isolated without arterial perfusion or centrifugal elutriation. Cx43 mRNA was present in 20-day-old rat Leydig cells, reached a plateau at day 40, and remained at high levels in 65- and 80-day-old rat Leydig cells. To evaluate the regulation of Cx43 gene expression, Leydig cells were cultured overnight and then treated with human chorionic gonadotropin (hCG) for variable periods of time. Addition of hCG (10 ng/ml) increased cytochrome P450 side-chain cleavage and steroidogenic acute regulatory protein mRNA levels and testosterone formation. However, Cx43 mRNA levels were inhibited by hCG in a time- and dose-dependent manner. Cx43 mRNA levels decreased 27% as early as 2 h after the addition of hCG and decreased 60% by 24 h. Treatment of Leydig cells with 8-bromo-cAMP (0.1 mM) for 6 and 24 h also reduced Cx43 mRNA levels by 36 and 56% respectively. Primary cultured Leydig cells stained strongly positive with anti-Cx43 monoclonal antibody. Treatment with hCG for 24 h reduced Cx43 signals and caused Cx43 to redistribute to the periphery of the cells. To evaluate the regulation of Cx43 in vivo, rats were treated with hCG (300 ng i.p.) and testes were removed 24 h later. Frozen section of testes revealed that these interstitial cells stained positive for 3beta-hydroxysteroid dehydrogenase (3beta-HSD) by histochemical staining and were positive for Cx43 by immunofluorescence staining. The adjacent seminiferous tubules stained only weakly positive for Cx43. Twenty-four hours after hCG treatment, 3beta-HSD activity increased while Cx43 immunostaining of Leydig cells was reduced. In conclusion, gap junction channels of Leydig cells are regulated by hCG both in vivo and in vitro. hCG increased Leydig cell steroidogenesis and steroidogenic enzyme mRNA levels but caused a redistribution of Cx43.
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PMID:Expression and regulation of connexin43 in rat Leydig cells. 1092 34

The matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) have been postulated to play a critical role in the extracellular matrix (ECM) remodeling associated with follicular development. The gelatinases were localized to the theca of developing follicles and in the stroma of the rodent ovary. Gelatinolytic activity corresponded with the localization of MMP-2 and MMP-9 around the developing follicles and at the apex of preovulatory follicles. The TIMPs-1, -2, and -3 were localized to the stroma and theca of developing follicles and correlation between MMPs and the quality of the developing follicles was found. During the process of ovulation, MMP-1 protein was found in the theca interna and externa, interstitial glands, and germinal epithelium. Synthetic inhibitor of mammalian tissue collagenases was documented to be inhibitory to ovulation in perfused rat ovaries. MMP-19 and TIMP-1 messenger RNA were localized to the granulosa and thecal-interstitial cells of large preovulatory and ovulating follicles. Both were induced and upregulated 5-10 fold by human chorionic gonadotropin (hCG). MMP-2 mRNA found in theca-interstitial cells and membrane-type (MT) 1-MMP mRNA found in granulosa and theca-interstitial cells were both induced after stimulation with pregnant mare's serum gonadotropin (PMSG). Gelatinolytic activity was observed throughout the formation of the corpus luteum. At 12 h after hCG, luteinizing granulosa cells expressed TIMP-1 and TIMP-3 mRNA. In the newly forming corpus luteum at 24 h after hCG administration, the luteal cells expressed TIMP-1, -2, and -3 mRNA with unique pattern of cellular expression for each of the TIMPs. Regression of the corpus luteum is associated with a significant increase in the activity of the metalloproteinases. In luteinized granulosa cells from women with polycystic ovarian syndrome (PCOS) the MMP-TIMP balance is shifted towards greater MMP activity. Cultured luteinized granulosa cells obtained from PCOS patients secrete higher levels of MMP-9 and MMP-2 compared to granulosa cells from normal ovulatory patients whereas the secreted basal level of TIMP-1 was similar in both types of granulosa cells. These results indicate a higher net gelatinolytic activity within the luteinizing granulosa cells of patients with PCOS. It has been shown that in sheep, diversion of normal follicles to atresia by hypophysectomy is followed by a significant increase of intrafollicular levels of MMP-2 and MMP-9 and the disappearance of connexin-43. It is therefore reasonable to speculate that MMP-9 and MMP-2 may be associated with inappropriate atresia in PCOS.
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PMID:MMPS and TIMPS in ovarian physiology and pathophysiology. 1535

Oocytes are held in meiotic arrest in prophase I until ovulation, when gonadotropins trigger a subpopulation of oocytes to resume meiosis in a process termed "maturation." Meiotic arrest is maintained through a mechanism whereby constitutive cAMP production exceeds phosphodiesterase-mediated degradation, leading to elevated intracellular cAMP. Studies have implicated a constitutively activated Galpha(s)-coupled receptor, G protein-coupled receptor 3 (GPR3), as one of the molecules responsible for maintaining meiotic arrest in mouse oocytes. Here we characterized the signaling and functional properties of GPR3 using the more amenable model system of Xenopus laevis oocytes. We cloned the X. laevis isoform of GPR3 (XGPR3) from oocytes and showed that overexpressed XGPR3 elevated intraoocyte cAMP, in large part via Gbetagamma signaling. Overexpressed XGPR3 suppressed steroid-triggered kinase activation and maturation of isolated oocytes, as well as gonadotropin-induced maturation of follicle-enclosed oocytes. In contrast, depletion of XGPR3 using antisense oligodeoxynucleotides reduced intracellular cAMP levels and enhanced steroid- and gonadotropin-mediated oocyte maturation. Interestingly, collagenase treatment of Xenopus oocytes cleaved and inactivated cell surface XGPR3, which enhanced steroid-triggered oocyte maturation and activation of MAPK. In addition, human chorionic gonadotropin-treatment of follicle-enclosed oocytes triggered metalloproteinase-mediated cleavage of XGPR3 at the oocyte cell surface. Together, these results suggest that GPR3 moderates the oocyte response to maturation-promoting signals, and that gonadotropin-mediated activation of metalloproteinases may play a partial role in sensitizing oocytes for maturation by inactivating constitutive GPR3 signaling.
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PMID:The Xenopus laevis isoform of G protein-coupled receptor 3 (GPR3) is a constitutively active cell surface receptor that participates in maintaining meiotic arrest in X. laevis oocytes. 1851 95


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