Disease relevance of OXYTOCIN

• Similar levels of the full-length p160 protein amplified in breast cancer 1 were recruited from HeLa nuclear extracts by the A2, pS2, B1, and OT ERE-bound receptors [1].
• The OT-induced InsP response was not altered by pertussis toxin (300 ng ml(-1), 2 h pretreatment), suggesting the involvement of a member of the Galpha(q) family [2].
• OT increased contractures in LTOT ewes [3].
• CSF AVP levels were significantly elevated in benign intracranial hypertension (2.1, SE 0.3 pmol/l) compared with controls (0.7, SE 0.1 pmol/l, p less than 0.001) but CSF OT concentrations were similar in both groups [4].
• Increases in plasma AVP and OT levels in response to both hypertonic saline and hemorrhage were markedly blunted in the hyponatremic rats compared to the normonatremic rats [5].

Psychiatry related information on OXYTOCIN

• In contrast, levels of autoAbs reacting with adrenocorticotropic hormone, OT, or VP had only few altered correlations with the Eating Disorder Inventory-2 subscale dimensions in AN and BN patients [6].
• Taken together, these data suggest that social interactions buffer against stress and promote wound healing through a mechanism that involves OT-induced suppression of the HPA axis [7].
• In the first subject, with polycystic ovarian disease, posterior pituitary peptide levels were in the normal range, whereas the other subject, recovering from anorexia nervosa, had raised plasma levels of all posterior pituitary peptides (AVP 8.1 pmol/l, OT 1.8 pmol/l, NPOT 131 pmol/l, mean values) despite a normal osmolality [8].
• Ovarian steroids and oxytocin (OT) have been implicated in the regulation of social behaviors [9].
• OXT-treated mice displayed milder withdrawal symptoms in response to increasing doses of peptide (0.2-2.0 IU) [10].

High impact information on OXYTOCIN

• Whereas steady state levels of OT mRNA were markedly increased throughout lactation, those of AVP mRNA were only transiently (initially) elevated, and the blood levels of these hormones were not significantly altered in lactating as compared with cycling virgin and postlactating rats [11].
• VP/OT hybrid precursor proteins have been identified immunocytochemically in enlarged cisternae of the rough endoplasmic reticulum, yet there is no evidence that the products can be secreted from affected cells [12].
• Because both vasopressinergic (V1) and oxytocinergic receptors have been demonstrated in the central nervous system, we asked whether specific antagonists of the V1, V2, and OXT receptor could antagonize the effects of these neuropeptides on passive avoidance behavior [13].
• Oxytocin (OXT) and [pGlu4,Cyt6]OXT-(4-8) have the opposite effect and attenuate passive avoidance behavior also when administered into the cerebral ventricle after the learning trial [13].
• The membrane properties of OT and VP neurons are generally similar in vitro, but the range of tests has not been extensive [14].

Chemical compound and disease context of OXYTOCIN

• In micropunches from the medial preoptic area (MPOA) OXY immunoreactive levels increased significantly in estrogen-progesterone-treated receptive animals (mean lordosis quotient (LQ) = 82.9 +/- 4.4) that were mounted by males over levels in estrogen-treated unreceptive animals (mean LQ = 2.3 +/- 1.3) [15].
• In hyperprolactinaemic females (22-41 y, n=6, three with pituitary adenomas), water retention was registered following an OWL, together with paradoxical AVP and OXT level increases, whereas the cortisol response remained normal, and the PRL level did not change at all [16].
• On the other hand, the pretreatment with the 5HT1A agonist buspirone significantly enhanced the OT response during hypoglycemia, without modifying the AVP rise [17].

Biological context of OXYTOCIN

• Combined immuno- and hybridization histochemical approaches were used to determine whether challenges that influence the synthesis and secretion of CRF, OT, and/or AVP result in altered expression in neurosecretory neurons of NGFI-B and another immediate-early gene, c-fos, which is widely used as a marker for functionally activated neurons [18].
• We assessed the ability of the ER to activate transcription of reporter plasmids containing either the consensus vitellogenin A2 ERE or the imperfect pS2, vitellogenin B1, or oxytocin (OT) ERE [1].
• Binding sites for AVP and OT could not be detected on mononuclear cells in peripheral blood of the rat [19].
• A similar OT level obtained by infusion of OT mimicked the renal responses to AUN without elevating blood pressure; however, only CAP but not V1-ant efficiently reversed OT-induced natriuresis [20].
• Thus, CAP reduced the natriuresis after AUN by interfering with OT- and not V1-receptors [20].

Anatomical context of OXYTOCIN

• In mammals, the magnocellular neurons of the supraoptic nucleus (SON) have been classified into vasopressin- (VP) and oxytocin- (OT) producing subtypes [14].
• In this study, employing in situ hybridization histochemistry, we have shown that CPH mRNA is abundantly expressed in the magnocellular paraventricular and supraoptic nuclei of the hypothalamus, the primary sites of OT and VP synthesis [21].
• Accordingly, iodo derivatives of NHH do not exhibit sufficient affinity to serve an specific ligands to measure OT, LVP, or AVP receptors in the uterus and kidney [22].
• Consistent with these results, only OT (10 microM) recruited PLCbeta(1) and PLCbeta(3) to myometrial plasma membranes [2].
• Regulation of vasopressin (VP) and oxytocin (OT) secretion involves integration of neural signals from hypothalamic osmoreceptors, ascending catecholaminergic and peptidergic cell groups in the brain stem, and local and autoregulatory afferents [23].

Associations of OXYTOCIN with other chemical compounds

• In sucrose gradient centrifugation of human neural lobes, each of these NPs had a distribution similar to that of either VP or OT [24].
• OT and arginine vasotocin (AVT) showed the highest PRL-releasing activity [25].
• When MIOT (10(-4) M) was preincubated with renal membranes for 10 min at 37 degrees C before addition of OT, it behaved as a noncompetitive inhibitor of NHH-stimulated adenylate cyclase [22].
• Capacity of the uterus to produce PG was evaluated after i.v. injection of 150 IU of oxytocin (OT) to IL- and DEXT-treated heifers Day 12 PP [26].
• In experiment 1, OT increased the secretion of PGE and PGF(2alpha) by granulosa cells collected from preovulatory follicles (before the LH/FSH surge) and OT production by pieces of follicle wall from periovulatory follicles (after the LH/FSH surge) was regulated by progesterone acting through the progesterone receptor [27].

Gene context of OXYTOCIN

• The role of OT was studied by infusion of the OT antagonist 1-deamino-2-D-Trp-4-Val-8-Orn-Oxytocin (OT-A, 0.5 microgram/kg min) for 6 h [28].
• OT at 25, 100, and 400 nM increased PRL release by 110%, 175%, and 270%, respectively; higher concentrations (1600 and 6400 nM) did not cause a further increase in PRL release [25].
• Using these RIAs, we found large amounts of AVT (up to 1.48 microgram/gland) in the chicken pituitary but no AVP or OT [29].
• In concert with our earlier discoveries, the present data support the hypothesis that HA-induced secretion of ACTH and beta-END is mediated via central activation of hypothalamic neuroendocrine neurons containing CRH, AVP, and/or OT [30].
• The responses of oxytocin (OXT) and prolactin (PRL) were more susceptible to epidural analgesia and were blocked at the C8-T2 level [31].

Analytical, diagnostic and therapeutic context of OXYTOCIN

• Brains were blocked and processed for OT/Fos immunohistochemistry [32].
• Orchidectomized males had an increased OT response to immobilization compared with sham-operated males (P less than 0.05) whereas the AVP response was not significantly changed [33].
• In contrast to other secretagogues, oxytocin (OT) elicited a smaller response in AP + PP cocultures than in AP cultures [34].
• Ovariectomy did not significantly affect either the AVP or OT responses [33].
• The hypothalamic magnocellular system of the adult female rhesus monkey is studied here, using immunoperoxidase technique and antisera to estrogen stimulated neurophysin (ESN), nicotine stimulated neurophysin (NSN), oxytocin (OT) and vasopressin (VP) [35].

References