Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A randomized study was undertaken to compare the effect of vaginal (1 mg of dinoprostone/2.5 ml gel) and intracervical (0.5 mg of dinoprostone in 2.5 ml of two different vehicles) on induction of labor and perinatal outcome. Sixty women (n = 20/20/20) who presented with an unfavorable cervix and a specific indication for the induction of labor participated in the study. There were no significant differences between the groups with respect to maternal age, weight, parity, gestational length or Bishop scores before prostaglandin E2 preinduction. Labour was induced with prostaglandin gel alone in twenty-two patients and with oxytocin infusion on the following morning after gel application in seven patients; altogether the rate of successful induction was 48.3%. The rate of uterine hyperstimulation was 16.7% with most cases in the groups receiving intracervical prostaglandin E2. Neonatal asphyxia diagnosed with umbilical vein and artery blood gas analysis was seen in eleven neonates who were delivered by labor induced with prostaglandin gel alone (50%). Prostaglandin pre-induction decreases the need for Cesarean sections in complicated pregnancies, but because of the risk of uterine hyperstimulation and neonatal asphyxia prostaglandins should be used only with specific indications.
 ...
PMID:Comparison of intravaginal and two intracervical prostaglandin E2 gels in pre-induction of labour. 809 77

Prostaglandin (PG) production by human amnion has been postulated to have a role in the onset of labor. Previous work by ourselves and others has demonstrated that oxytocin, phorbol esters and epidermal growth factor (EGF) increase PGE2 production in human amnion cells by activation of the Phospholipase C/Protein Kinase C (PKC) cascade system. The present study was undertaken to determine the effect of prior activation of the Adenylate Cyclase cascade system upon subsequent stimulation of PGE2 production by oxytocin, phorbol 12-myristate-13-acetate (PMA) or EGF in amnion cells and membrane discs. Isoproterenol, forskolin and dibutyryl cyclic adenosine monophosphate (dbcAMP) were utilized to activate the Adenylate Cyclase system at the receptor, enzyme and second messenger level. In control amnion cells, oxytocin, PMA and EGF each provoked dose dependent increases in PGE2 production. In cells preincubated with dbcAMP, forskolin or isoproterenol, agonist stimulated PGE2 production was markedly (50-90%) inhibited (p < 0.01). Inhibition was dose dependent upon preincubator concentrations. Maximal inhibition by adenylate cyclase activators occurred with 2-4 h of preincubation. In membrane discs, forskolin preincubation also inhibited oxytocin, PMA and EGF stimulation of PGE2 production. Activation of the Adenylate Cyclase system in human amnion cells or membrane discs inhibits the subsequent action of potent stimulators of PGE2 production in human amnion.
 ...
PMID:Protein kinase A activators inhibit agonist induced prostaglandin production in human amnion. 839 7

During the period between July 1, 1993 and July 31, 1994 the authors preinduced 52 pregnant women in term using the cervical dilatator Dilapan. The group comprised patients with single pregnancies > 38 weeks, vertex presentation, cervical score < 5 and reactive NST. They introduced into the cervical canal 4 Dilapan rods for 12-18 hours and after extraction of the rods, depending on the finding, the patients were induced with Prostaglandin e.a. or oxytocin i.v. The preinduction was successful in 46 patients (88.5 per cent), in 16 patients (30.8 per cent) uterine contractions were induced by Dilapan alone. Forceps delivery was performed 4 times (7.7 per cent) and Caesarean section 12 times (23.1 per cent). Apart from pain in the hypograstrium resembling menstruation pain, no side-effects were recorded. There were no irregularities such as the length of labour stages, blood loss due to injury during labour and the incidence of neonatal hypoxia. Based on the described experience Dilapan can be recommended as a preinduction method for maturation of the portio uteri.
 ...
PMID:[Induction of cervix ripening with hydrophilic Dilapan rods in pregnancy at term]. 858 48

Prostaglandin (PG) F2alpha that is released from the uterus is essential for spontaneous luteolysis in cattle. Although PGF2alpha and its analogues are extensively used to synchronize the estrous cycle by inducing luteolysis, corpora lutea (CL) at the early stage of the estrous cycle are resistant to the luteolytic effect of PGF2alpha. We examined the sensitivity of bovine CL to PGF2alpha treatment in vitro and determined whether the changes in the response of CL to PGF2alpha are dependent on progesterone (P4), oxytocin (OT), and PGs produced locally. Bovine luteal cells from early (Days 4-5 of the estrous cycle) and mid-cycle CL (Days 8-12 of the estrous cycle) were preexposed for 12 h to a P4 antagonist (onapristone: OP; 10(-4) M), an OT antagonist (atosiban: AT; 10(-6) M), or indomethacin (INDO; 10(-4) M) before stimulation with PGF2alpha. Although OP reduced P4 secretion (p < 0.001) only in early CL, it reduced OT secretion in the cells of both phases examined (p < 0.001). OP also reduced PGF2alpha and PGE2 secretion (p < 0.01) from early CL. However, it stimulated PGF2alpha secretion in mid-cycle luteal cells (p < 0.001). AT reduced P4 secretion in early and mid-cycle CL (p < 0.05). Moreover, PGF2alpha secretion was inhibited (p < 0.05) by AT in early CL. The OT secretion and the intracellular level of free Ca2+ ([Ca2+]i) were measured as indicators of CL sensitivity to PGF2alpha. PGF2alpha had no influence on OT secretion, although [Ca2+]i increased (p < 0.05) in the early CL. However, the effect of PGF2alpha was augmented (p < 0.01) in cells after pretreatment with OP, AT, and INDO in comparison with the controls. In mid-cycle luteal cells, PGF2alpha induced 2-fold increases in OT secretion and [Ca2+]i. However, in contrast to results in early CL, these increases were magnified only by preexposure of the cells to AT (p < 0.05). These results indicate that luteal P4, OT, and PGs are components of an autocrine/paracrine positive feedback cascade in bovine early to mid-cycle CL and may be responsible for the resistance of the early bovine CL to the exogenous PGF2alpha action.
 ...
PMID:Sensitivity of bovine corpora lutea to prostaglandin F2alpha is dependent on progesterone, oxytocin, and prostaglandins. 1033 83

We investigated the half-life of oxytocin in reproductively normal mares and the prostaglandin response after oxytocin administrations. Mares were given oxytocin, 10 or 25 iu, i.v., on the day of, or 2 days after, ovulation, and frequent jugular blood samples were collected for analysis of oxytocin and Prostaglandin F metabolite (PGFM) by RIA. Neither dose of oxytocin nor day of treatment affected the half-life of the exogenous oxytocin, which was determined to be 6.8 min. A significant increase in PGFM was observed within 6 min of oxytocin administration and peak values were observed within 10 min. PGFM response after oxytocin administration on the day of ovulation appeared elevated compared to the response 2 days after ovulation.
 ...
PMID:PGFM response to exogenous oxytocin and determination of the half-life of oxytocin in nonpregnant mares. 1045 85

The ruminant corpus luteum, in addition to producing progesterone, synthesizes and secretes oxytocin (OT) during the estrous cycle. Secretion of oxytocin occurs by exocytosis of membrane-encapsulated granules of this hormone. Exocytosis of oxytocin involves transport of granules through a cytoskeletal matrix including an actin cortex closely associated with the plasma membrane (PM). Actin filaments crosslinked by various proteins give rise to the structural integrity of the cortex. Myristoylated alanine-rich C kinase substrate (MARCKS), a protein specifically phosphorylated by protein kinase C (PKC), crosslinks actin filaments and anchors the actin network to the inner leaflet of the PM. There is evidence that the intact actin cortex may serve as a barrier, precluding fusion of transport vesicles with the PM. In some secretory cells, phosphorylation of MARCKS has resulted in its translocation from the PM to the cytoplasm with an associated disassembly of the actin cortex. Prostaglandin F(2alpha) (PGF(2alpha)) stimulation of the bovine corpus luteum during the midluteal phase of the estrous cycle activates PKC, which is associated with an increase in OT secretion in vivo and in vitro. Data are presented demonstrating that stimulation of bovine luteal cells with PGF(2alpha) on Day 8 of the cycle promotes rapid phosphorylation of MARCKS protein and causes its translocation from the PM to the cytoplasm and concomitant, enhanced exocytosis of OT. These data are consistent with the premise that MARCKS plays a role in the exocytotic process.
 ...
PMID:Phosphorylation of myristoylated alanine-rich C kinase substrate (MARCKS) protein is associated with bovine luteal oxytocin exocytosis. 1085 36

Intra-amniotic infection leads to preterm labor and is associated with the local release of inflammatory cytokines by fetal membranes, resulting in the production of uterotonic prostaglandins. Oxytocin, however, also plays a key role in the initiation of labor. Short-term exposure of myometrium to interleukin (IL)-1 enhances oxytocin signaling and contractility. With intrauterine infection, however, myometrium is exposed to inflammatory cytokines for prolonged periods. The present study was conducted to demonstrate that myometrial oxytocin signaling is significantly impaired following prolonged exposure to IL-1. Myometrial cells were treated with IL-1 for 24 h. Oxytocin-stimulated inositol trisphosphate (IP(3)) production was measured in tritiated myoinositol-loaded myometrial cells. Arachidonic acid (AA) release was measured in tritiated AA-loaded myometrial cells. Increases in intracellular calcium were measure with fluo-3. Prostaglandin (PG) F(2alpha) and 6-keto-PGF(1alpha) were measured by ELISA assay. Prolonged exposure of myometrial cells to IL-1 resulted in a significant reduction in oxytocin-mediated signaling as measured by IP(3) production and AA release, as well as a decrease in intracellular calcium. Prolonged exposure of myometrial cells to IL-1, however, resulted in enhanced PG release. Oxytocin may not contribute significantly to the labor-inducing action of IL-1 in the setting of preterm labor with prolonged infection.
 ...
PMID:Oxytocin signaling in human myometrium is impaired by prolonged exposure to interleukin-1. 1095 30

Although prostaglandin (PG) F(2alpha) released from the uterus has been shown to cause regression of the bovine corpus luteum (CL), the neuroendocrine, paracrine, and autocrine mechanisms regulating luteolysis and PGF(2alpha) action in the CL are not fully understood. A number of substances produced locally in the CL may be involved in maintaining the equilibrium between luteal development and its regression. The present study was carried out to determine whether noradrenaline (NA) and nitric oxide (NO) regulate the sensitivity of the bovine CL to PGF(2alpha) in vitro and modulate a positive feedback cascade between PGF(2alpha) and luteal oxytocin (OT) in cows. Bovine luteal cells (Days 8-12 of the estrous cycle) cultured in glass tubes were pre-exposed to NA (10(-5) M) or an NO donor (S-nitroso-N:-acetylpenicillamine [S-NAP]; 10(-4) M) before stimulation with PGF(2alpha) (10(-6) M). Noradrenaline significantly stimulated the release of progesterone (P(4)), OT, PGF(2alpha), and PGE(2) (P: < 0.01); however, S-NAP inhibited P(4) and OT secretion (P: < 0.05). Oxytocin secretion and the intracellular level of free Ca(2+) ([Ca(2+)](i)) were measured as indicators of CL sensitivity to PGF(2alpha). Prostaglandin F(2alpha) increased both the amount of OT secretion and [Ca(2+)](i) by approximately two times the amount before (both P: < 0.05). The S-NAP amplified the effect of PGF(2alpha) on [Ca(2+)](i) and OT secretion (both P: < 0.001), whereas NA diminished the stimulatory effects of PGF(2alpha) on [Ca(2+)](i) (P: < 0.05). Moreover, PGF(2alpha) did not exert any additionally effects on OT secretion in NA-pretreated cells. The overall results suggest that adrenergic and nitrergic agents play opposite roles in the regulation of bovine CL function. While NA stimulates P(4) and OT secretion, NO may inhibit it in bovine CL. Both NA and NO are likely to stimulate the synthesis of luteal PGs and to modulate the action of PGF(2alpha). Noradrenaline may be the factor that is responsible for the limited action of PGF(2alpha) on CL and may be involved in the protection of the CL against premature luteolysis. In contrast, NO augments PGF(2alpha) action on CL and it may be involved in the course of luteolysis.
 ...
PMID:Influence of nitric oxide and noradrenaline on prostaglandin F(2)(alpha)-induced oxytocin secretion and intracellular calcium mobilization in cultured bovine luteal cells. 1099 20

This review of the physiology of ovarian contractility cites the functions of FSH and LH and the contribution of chorionic gonadotropin (HCG) to follicular swelling and rupture. Endogenous estrogen priming seems to be needed for this response. Luteninizing hormone releasing hormone (LHRH) administered during the ovulatory phase also causes changes to occur in ovaries treated with smooth muscle stimulants. A contractile response may be induced by alpha-adrenergic receptors, which confirms the finding of smooth muscle fibers in the ovaries. Spontaneous contractions have also been observed in ovaries removed from animals at estrus. Estrogen activate, progesterone inhibits ovarian contractility. In rabbits and guinea pigs spontaneous activity of the ovary is increased during early pregnancy. Treatment with nor- epinephrine inhibits this. Quiescent ovaries show marked activation with nor-adrenergic compounds such as nor-epinephrine and phenilephrine. Pretreatment with alpha-adrenergic blocking agents such as progranolol reverses this effect. Prostaglandin F-2-alpha is a more powerful stimulant on ovarian motility than vasopressin or oxytocin. The role of ovarian contractions in the reproductive function is still unknown. Further studies may provide ways of interfering with reproduction at the ovarian level.
 ...
PMID:Ovarian contractility and ovulation. 1225 6

A review of the current state of knowledge of oxytocin production by the preovulatory follicle and corpus luteum is presented. Corpora lutea of a number of mammalian species have been found to synthesize oxytocin. However, the synthesis and secretion of this nanopeptide by the corpus luteum of the ruminant has been most extensively studied because of the potential role of this peptide in facilitating luteal regression. While much information exists relative to various biochemical and endocrine factors that impact on oxytocin gene expression, this aspect about luteal synthesis of this peptide hormone remains enigmatic. Prostaglandin F-2alpha (PGF-2alpha) has been shown to be a primary endogenous hormone responsible for triggering luteal secretion of oxytocin. Details are provided regarding the PGF-2alpha-induced intracellular signal transduction pathway that ultimately results in exocytosis of luteal oxytocin. Evidence is also presented for potential autocrine/paracrine actions of oxytocin in regulating progesterone production by luteal and granulosa cells. Concluding remarks highlight aspects about luteal oxytocin production that require further research.
 ...
PMID:Biochemical and endocrine aspects of oxytocin production by the mammalian corpus luteum. 1461 32


<< Previous 1 2 3 4 5 6 Next >>