Disease relevance of OXT

• We present a Raman and surface-enhanced Raman scattering (SERS) study of the following proteins containing S-S group(s): alpha chymotrypsin (alpha-CHT), insulin, lysozyme, oxytocin (OXT), Streptomyces subtilisin inhibitor (SSI), and trypsin inhibitor (STI) [1].
• Mechanisms underlying the pathogenicity of diabetes insipidus mutations were probed by studying their effects on the properties of bovine oxytocin-related neurophysin [2].
• To address this issue, the disulfide-rich precursor of oxytocin-associated bovine neurophysin was expressed in Escherichia coli and folded in vitro to yield milligram quantities of purified protein; evidence of significant impediments to yield resulting from damage to Cys residues is presented [3].
• Concentrations of 10(-10) mol/l to 10(-1) mol/l suppressed progesterone secretion in a log dose-related manner (r = 0.97) with evidence of toxicity (lower oxytocin concentrations and significantly reduced DNA compared with controls) [4].
• Endometria from pregnant cows did not respond to oxytocin when perifused at 39 degrees C. However, PGF secretion rates from endometrium of pregnant cows increased (P less than 0.01) in response to oxytocin when perifused under heat stress conditions.(ABSTRACT TRUNCATED AT 250 WORDS)[5]

Psychiatry related information on OXT

• Physiological regulation of maternal behavior in heifers: roles of genital stimulation, intracerebral oxytocin release, and ovarian steroids [6].
• Feeding during milking enhances milking-related oxytocin secretion and milk production in dairy cows whereas food deprivation decreases it [7].
• When oxytocin was injected first, the correlation coefficient for the time-response relationship was -0.98 [8].
• Continuous ultrasound cross-sections during milk ejection induced by exogenous oxytocin were performed to record the latency period of milk ejection [9].
• Thus, individual differences in uterine secretion of PGF2 alpha in response to oxytocin were related to stage of the cycle and to differences in the endogenous ovarian steroid environment within each stage of the estrous cycle [10].

High impact information on OXT

• The organization of these precursors has been established by sequence determination of cloned bovine cDNAs encoding prepro-arginine vasopressin-neurophysin II (prepro-AVP-NPII) and prepro-oxytocin-neurophysin I (prepro-OT-NPI) [11].
• Recent gene conversion involving bovine vasopressin and oxytocin precursor genes suggested by nucleotide sequence [11].
• We have recently investigated the presence of immunoreactive vasopressin and the related nonapeptide oxytocin in the adrenal glands of the human, rat and cow, and report here the isolation from the Brattleboro rat adrenal of material with similar immunological, physical and biological properties to synthetic vasopressin [12].
• Expression of the vasopressin and oxytocin genes has been described so far only in the hypothalamus [13].
• When calculating the relative amounts per organ, the active corpus luteum produces approximately 250 times more oxytocin mRNA than a single hypothalamus [13].

Chemical compound and disease context of OXT

• We tested the hypotheses that 1) epidural anesthesia at parturition would block both peripheral and central release of oxytocin and eliminate the development of maternal behavior in primiparous heifers and 2) estradiol priming, genital stimulation, and appropriate neonatal stimuli would induce maternal behavior in nulliparous heifers [6].
• In this study, we evaluated the effects of several hormones (i.e. growth hormone, prolactin, vitamin D3, luteinizing hormone, oxytocin) on the phagocytosis and intracellular survival of Mycobacterium avium ss. paratuberculosis within bovine peripheral blood monocytes [14].
• Groups SC-OT and OT-OT received oxytocin twice daily (12 h apart) (0.33 USP units/kg body weight, s.c.) on Days 3 to 6 of the estrous cycle following cloprostenol-induced luteolysis, while Groups SC-SC and OT-SC received an equivalent volume of saline [15].
• Intramammary pressure (IMP) within the teat cistern was measured in six cows before and after i.v. injection of 0 or 20 micrograms Atosiban/kg body weight and repeated injections of 0.2 or 0.5 i.u. oxytocin [16].

Biological context of OXT

• The extracted AVP and oxytocin had identical retention times to those of the synthetic peptides on high-performance liquid chromatography (HPLC) and were biologically active in assays for antidiuretic and milk-ejection activity (with potencies of 310 units/mg and 340 units/mg respectively) [17].
• Scatchard plots showed that each ligand interacted with a single high-affinity, low-capacity binding site: oxytocin dissociation constant (Kd) 3.1 +/- 0.29 nmol/l, maximum binding capacity (Bmax) 89.6 +/- 18.4 fmol/mg protein (n = 3); AVP Kd 0.73 +/- 0.02 nmol/l, Bmax 26.5 +/- 8.3 fmol/mg protein (n = 3).(ABSTRACT TRUNCATED AT 250 WORDS)[17]
• In the present study, the oestrogen-dependent up-regulation of the bovine oxytocin promoter is investigated in MDA-MB 231 cells [18].
• Transcriptional activation of the oxytocin promoter by oestrogens uses a novel non-classical mechanism of oestrogen receptor action [18].
• Oxytocin and vasopressin receptors in bovine endometrium and myometrium during the estrous cycle and early pregnancy [19].

Anatomical context of OXT

• Arginine vasopressin and oxytocin in the bovine adrenal gland [17].
• Oxytocin, NpI and AVP were assayed in five subcellular fractions of bovine adrenal medulla prepared on discontinuous sucrose gradients [17].
• The concentrations of immunoreactive oxytocin and arginine vasopressin (AVP) and their respective neurophysins (NpI and NpII) were compared in bovine adrenal cortex and medulla [17].
• Simultaneous measurement of arginine vasopressin and oxytocin in plasma and neurohypophyses by radioimmunoassay [20].
• Samples were collected from jugular vein at 15-min intervals for 30 min before and 3 h after the injection of OT [21].

Associations of OXT with chemical compounds

• The nonapeptide hormone oxytocin-like arginine-vasopressin (AVP) is synthesized as part of a larger precursor polypeptide [22].
• Because OTA inhibits OT-induced release of endometrial prostaglandin F2alpha it may be a good tocolytic agent [21].
• The effect of OTA on OT-induced increase in plasma concentration of 13,14-dihydro-15-keto-prostaglandin F2alpha metabolite (PGFM) was studied in 24 late-pregnant cows [21].
• Small doses (10 pM/ml) of exogenous progesterone or estradiol stimulated a surge in OT, while the intermediate doses (100 or 1000 pM/ml) had no influence, and large doses (10,000 pM/ml) inhibited OT secretion by granulosa cells [23].
• OT (1, 10, 100 or 1000 mIU/ml) stimulates both progesterone and estradiol output [23].

Physical interactions of OXT

• In bovine ovary the number of arginine vasopressin binding sites was approximately 50% lower than oxytocin binding sites and the cyclic variations were not significant [24].
• The high concentration of oxytocin within the corpus luteum coupled with the presence of bovine neurophysin I suggests that oxytocin is synthesized locally [25].
• In contrast, the levels of oxytocin receptor mRNA and specific binding sites for oxytocin in granulosa cells had decreased significantly at 12 and 24 h post-GnRH [26].
• Oxytocin then binds to its endometrial receptors and initiates luteolytic pulses of PGF-2 alpha [27].

Enzymatic interactions of OXT

• The oxytocin precursor was cleaved off the fusion protein by cyanogen bromide treatment, chromatographed on FPLC columns and identified by Western blot analysis, using antibodies raised against neurophysin [28].

Regulatory relationships of OXT

• The gene for the hypothalamic peptide hormone oxytocin is highly expressed in the bovine corpus luteum: biosynthesis, structure and sequence analysis [13].
• The release of oxytocin was stimulated by bFGF in a dose-dependent manner [29].
• When luteal cells were cultured with growth factors, only TGF-beta showed a dose-dependent inhibition of both basal and LH-stimulated progesterone as well as oxytocin release (measured between 48 and 52 h of culture) [29].
• The oxytocin-induced membrane changes were suppressed when oocytes were pretreated with an oxytocin receptor antagonist [30].
• Down-regulation of oxytocin-induced cyclooxygenase-2 and prostaglandin F synthase expression by interferon-tau in bovine endometrial cells [31].

Other interactions of OXT

• Low concentrations (10 nM) of angiotensin II, bradykinin, histamine, arginine-vasopressin, and bombesin, and high (10 microM) concentrations of oxytocin, prostaglandins E1, and E2, beta-endorphin, and neurotensin stimulated significant accumulation of [3H]inositol phosphates in adrenal medullary cells preloaded with [3H)]inositol [32].
• The transfected ovarian cells were cultured with and without bLH (100 ng/ml), bGH (100 ng/ml), IGF-I (10 ng/ml), oxytocin (10 ng/ml) and oestradiol-17beta (100 ng/ml) [33].
• Accumulation of cyclooxygenase-2 gene transcripts in uterine tissues of pregnant and parturient cows: stimulation by oxytocin [34].
• The release of IGFBP-3, progesterone, oxytocin, IGF-I and prostaglandins F (PGF) and E (PGE) by control and transfected cells was compared [33].
• NGF had an inhibitory effect only on the basal release of oxytocin. bFGF had no effect on the release of either hormone under continuous stimulation in cell culture [29].

Analytical, diagnostic and therapeutic context of OXT

• The specificity of the immunoprecipitation was demonstrated by competition with excess amounts of unlabeled neurophysin II or arginine vasopressin; little or no competition was observed with unlabeled neurophysin II or arginine vasopressin; little or no competition was observed with unlabeled neurophysin I or oxytocin [35].
• Fractions of gel chromatography effluent and extract of SDS-PAGE gel slices were subjected to RIA for immunoreactive precursors of AVP, AVP-NP, OT, and OT-NP using specific antisera fro each molecule [36].
• In the present experiments we studied basal, prostaglandin (PG) F2 alpha-stimulated and ascorbate-stimulated OXT release from individual bovine luteal cells utilizing the reverse hemolytic plaque assay (RHPA) [37].
• Oxytocinyl-GKR was shown by analytical affinity chromatography to bind noncovalently to neurophysin with an affinity close to that of mature oxytocin [38].
• When activin-A was withdrawn from the cell culture after 72 h and the incubation continued for a further 72 h, a recovery in OT was seen on day 4 and 5 after activin-A doses of 0.1-1 ng/ml, but not after higher doses (3 and 10 ng/ml) [39].

References