The activities of corticotropin-releasing factor(CRF) and related peptides are mediated a number of receptors with seven transmembrane domains that are coupled to the Gs and Gq proteins. These receptors are known as C...The activities of corticotropin-releasing factor(CRF) and related peptides are mediated a number of receptors with seven transmembrane domains that are coupled to the Gs and Gq proteins. These receptors are known as CRF-Rs. In vitro studies have evidenced that urocortin(UCN) and CRF provoke an increase in the contractility of the uterus which is induced by endometrial prostaglandin F2 a. Furthermore, through trophoblasts, it stimulates the secretion of adrenocorticotropic hormone(ACTH) and prostaglandin PGE2 and has a vasodilatory effect on the placenta. While it is well known that the placenta produces considerable quantities of CRF, several studies have, however, excluded that the placenta can generate significant quantities of UCN. In the short term, the human fetal adrenal gland produces more cortisol and dehydroepiandrosterone sulfate. The gestational tissues express UCN3 and UCN2 m RNA in cytotrophoblast and syncytiotrophoblast cells, while UCN2 is only to be found in the maternal and fetal vessels and amniotic cells. Nevertheless, gestational tissues express UCN2 and UCN3 differentially and do not stimulate placental ACTH secretion. In term pregnancies, maternal plasma levels of CRF and UCN are lower than at the beginning of pregnancy and are correlated to labor onset. Conversely,they do not decrease in post-term pregnancies. This evidence would seem to indicate that the fine-regulated expression of these neuropeptides is important in determining the duration of human gestation. In this scenario, low concentrations of UCN in the amniotic fluid at mid-term may be considered a sign of predisposition to preterm birth.展开更多
Objective: To localize where urocortin is expressed in human tissue in an attempt to study its physiological functions. Methods: Expression of immunoreactive urocortin in different human tissue was examined using a sp...Objective: To localize where urocortin is expressed in human tissue in an attempt to study its physiological functions. Methods: Expression of immunoreactive urocortin in different human tissue was examined using a specific urocortin antibody and the immunoperoxidase staining method. Results: Immunoreactive urocortin was observed in the anterior pituitary cells, decidual stromal cells, syncytiotrophoblasts, amnion epithelium. the vascular smooth muscles of myometrium, fallopian tube and small intestine. Conclusion: The study indicates that urocortin is expressed in some specific areas of human tissue. The data are consistent with the hypothesis that urocortin is produced locally as an endocrine factor, which may act as a neural regulator and a regulator of local blood flow.展开更多
目的探讨Urocortin(Ucn)对自发性高血压大鼠(SHR)胸主动脉舒缩功能的作用及机制。方法采用体外血管灌流,观察Ucn对SHR胸主动脉的舒张作用,以及左旋硝基精氨酸甲酯(N(ω)n itro-L-argin ine methyl ester,L-NAME)、亚甲蓝(M ethylene B l...目的探讨Urocortin(Ucn)对自发性高血压大鼠(SHR)胸主动脉舒缩功能的作用及机制。方法采用体外血管灌流,观察Ucn对SHR胸主动脉的舒张作用,以及左旋硝基精氨酸甲酯(N(ω)n itro-L-argin ine methyl ester,L-NAME)、亚甲蓝(M ethylene B lue,MB)和格列本脲(G lybenc lam ide)对其舒张作用的影响。结果Ucn(1 nmol.L-1~1μmol.L-1)可明显舒张内皮完整和去内皮SHR胸主动脉(P<0.01),此作用具有剂量依赖性;一氧化氮(NO)合成酶抑制剂L-NAME(100μmol.L-1)和鸟苷酸环化酶(GC)抑制剂MB部分抑制Ucn舒张血管的作用,而且增强去甲肾上腺素(NE)产生的收缩反应。ATP敏感钾通道(KATP)阻断剂格列本脲(10μmol.L-1)可减弱Ucn的舒血管作用。结论Ucn对SHR血管具有内皮依赖性和非内皮依赖性舒张作用,此作用部分是Ucn增加血管内皮细胞NO水平实现的,并且与NO-cGMP通路和KATP通道有关。展开更多
Urocortin,a novel peptide of the cortiotropin releasiong hormone(CRH)family,was discovered in 1995 in the rat brain and subsequently cloned and localized to human chromosome 2.It can bind to both CRH type 1 receptor a...Urocortin,a novel peptide of the cortiotropin releasiong hormone(CRH)family,was discovered in 1995 in the rat brain and subsequently cloned and localized to human chromosome 2.It can bind to both CRH type 1 receptor and CRH type 2 receptor,as well as CRH binding protein.Especially to CRH type 2 receptor,urocortin binds to it with 40 times more potency than CRH does.Therefore,urocortin is thought to be an endogenous ligand for CRH type 2 receptor.Immunoreactive urocortin and urocortin mRNA were localized in many areas such as mammalian brain,cardiovascular system,placenta.It is believed that urocortinmay play important physiological roles as a neuropeptide not only in the central nervous system but also in peripheral tissues.展开更多
文摘The activities of corticotropin-releasing factor(CRF) and related peptides are mediated a number of receptors with seven transmembrane domains that are coupled to the Gs and Gq proteins. These receptors are known as CRF-Rs. In vitro studies have evidenced that urocortin(UCN) and CRF provoke an increase in the contractility of the uterus which is induced by endometrial prostaglandin F2 a. Furthermore, through trophoblasts, it stimulates the secretion of adrenocorticotropic hormone(ACTH) and prostaglandin PGE2 and has a vasodilatory effect on the placenta. While it is well known that the placenta produces considerable quantities of CRF, several studies have, however, excluded that the placenta can generate significant quantities of UCN. In the short term, the human fetal adrenal gland produces more cortisol and dehydroepiandrosterone sulfate. The gestational tissues express UCN3 and UCN2 m RNA in cytotrophoblast and syncytiotrophoblast cells, while UCN2 is only to be found in the maternal and fetal vessels and amniotic cells. Nevertheless, gestational tissues express UCN2 and UCN3 differentially and do not stimulate placental ACTH secretion. In term pregnancies, maternal plasma levels of CRF and UCN are lower than at the beginning of pregnancy and are correlated to labor onset. Conversely,they do not decrease in post-term pregnancies. This evidence would seem to indicate that the fine-regulated expression of these neuropeptides is important in determining the duration of human gestation. In this scenario, low concentrations of UCN in the amniotic fluid at mid-term may be considered a sign of predisposition to preterm birth.
文摘Objective: To localize where urocortin is expressed in human tissue in an attempt to study its physiological functions. Methods: Expression of immunoreactive urocortin in different human tissue was examined using a specific urocortin antibody and the immunoperoxidase staining method. Results: Immunoreactive urocortin was observed in the anterior pituitary cells, decidual stromal cells, syncytiotrophoblasts, amnion epithelium. the vascular smooth muscles of myometrium, fallopian tube and small intestine. Conclusion: The study indicates that urocortin is expressed in some specific areas of human tissue. The data are consistent with the hypothesis that urocortin is produced locally as an endocrine factor, which may act as a neural regulator and a regulator of local blood flow.
文摘Urocortin,a novel peptide of the cortiotropin releasiong hormone(CRH)family,was discovered in 1995 in the rat brain and subsequently cloned and localized to human chromosome 2.It can bind to both CRH type 1 receptor and CRH type 2 receptor,as well as CRH binding protein.Especially to CRH type 2 receptor,urocortin binds to it with 40 times more potency than CRH does.Therefore,urocortin is thought to be an endogenous ligand for CRH type 2 receptor.Immunoreactive urocortin and urocortin mRNA were localized in many areas such as mammalian brain,cardiovascular system,placenta.It is believed that urocortinmay play important physiological roles as a neuropeptide not only in the central nervous system but also in peripheral tissues.
