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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Competition with specific oligonucleotides in DNA-binding experiments, polyacrylamide gel electrophoresis, and recognition by specific antibodies have identified the ubiquitous transcription factor COUP as one of the nuclear proteins binding to the promoter region of the bovine oxytocin gene in endogenously expressing bovine granulosa cells. PCR cloning of partial cDNA sequences for bovine COUP-TF I and II and development of RNase protection assays demonstrated the up-regulation of COUP-TF in bovine granulosa cells and corpus luteum under conditions where the oxytocin gene is switched off. These experimental results from in vitro and in vivo studies point to the direct involvement of COUP-TF in oxytocin gene down-regulation during luteinization of bovine granulosa cells.
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PMID:The COUP transcription factor (COUP-TF) is directly involved in the regulation of oxytocin gene expression in luteinizing bovine granulosa cells. 144 99

Sequence analysis of the rat vasopressin and oxytocin gene family reveals that the two genes are linked by a long interspersed repeated DNA element (LINE) giving rise to seven long open reading frames encoding hypothetical proteins of 99 to 556 amino acid residues. Furthermore, although both DNA strands of LINEs serve as templates for transcription, transcripts initiated at the 3' end are more abundant than those started from the 5' end. The LINEs are transcribed preferentially in brain tissues as analyzed by Northern blot, in situ hybridization, and RNase protection experiments. The data show that most LINEs are transcribed at their entire length and that a major fraction of respective RNAs does not enter the cytoplasm but remains in the cell nucleus.
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PMID:Rat vasopressin and oxytocin genes are linked by a long interspersed repeated DNA element (LINE): sequence and transcriptional analysis of LINE. 170 87

Lysine vasopressin- and oxytocin-encoding mRNAs have been analysed in the developing hypothalamus of the pig. The two hormone-encoding mRNAs were first detectable on fetal day 49 by Northern blot analysis. Whereas RNase mapping revealed identical transcripts throughout the developmental stages studied, Northern blots showed that the early transcripts appeared to be shorter (by 100-200 nucleotides) and more heterogeneous in size than those of later stages. This developmentally related length polymorphism was shown to be due to different poly(A) lengths and was abolished by removal of the poly(A) tails with RNase H. These results indicate that maturation of neurones in the developing porcine hypothalamus is accompanied by an increase in length of the poly(A) tail of vasopressin and oxytocin mRNAs.
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PMID:Poly(A) tail length of oxytocin- and lysine vasopressin-encoding mRNAs increases during development in the porcine hypothalamus. 197 13

In rats, vasopressin- and oxytocin-encoding mRNAs are present in the posterior but absent in the anterior lobe of the pituitary gland. RNase protection experiments indicate that in the posterior pituitary and hypothalamus identical transcriptional start points are used. Furthermore, the two transcripts from posterior pituitary and hypothalamus show identical nucleotide sequences. Animals operated by paired electrical lesions in such a way that connections between the supraoptic nucleus (SON) and paraventricular nucleus (PVN) of the hypothalamus and the posterior pituitary lobe are destroyed continue to express the vasopressin and oxytocin gene in the hypothalamus but not in the posterior pituitary. Operated animals subjected to chronic intermittent salt loading for 6 days similarly contain vasopressin and oxytocin encoding transcripts in the hypothalamus but not in the posterior pituitary.
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PMID:Rats with physically disconnected hypothalamo-pituitary tracts no longer contain vasopressin-oxytocin gene transcripts in the posterior pituitary lobe. 233 37

A solution hybridization/RNase protection assay for the molar quantitation of vasopressin and oxytocin mRNAs, using synthetic complementary RNA probes, is described. This assay was optimized to permit the identification of vasopressin (AVP) mRNAs containing the frame-shift point deletion causing inheritable diabetes insipidus in the Brattleboro strain of rat. Examination of RNA from hypothalamic magnocellular tissue punches found that of the 86.1 x 10(-18) mol [86.1 attomoles (amol)] of AVP mRNA detected in the Brattleboro heterozygote paraventricular (PVN) nucleus, 5.2% could be shown to be mutant AVP mRNA (AVPd RNA). The percentage of AVPd RNA increased dramatically to 18.1% after 6 d of chronic intermittent salt-loading. Similar percentages and percentage increases of AVPd RNA were detected in the heterozygote supraoptic nucleus (SON). These values were contrasted with those found in parallel studies in both Long Evans and Brattleboro homozygotes, and compared with values for oxytocin (OT) mRNA in all 3 AVP rat genotypes. The results of continued osmotic regulation of the mutant AVP gene, the low native levels of AVPd RNA found in both the Brattleboro heterozygote and homozygote, and the magnitudes of AVPd expression change with chronic osmotic challenge were interpreted as indicating that (1) in the diploid rat genome, both AVP alleles are transcribed, (2) the osmotic regulation of the mutant AVP gene is normal, and (3) the low levels of AVPd mRNA are consistent with a shorter-than-control effective mRNA half-life.
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PMID:Differential expression of vasopressin alleles in the Brattleboro heterozygote. 319 79

The bovine oxytocin gene has been expressed in the testes of two independent transgenic mouse lines. Hybridization and RNase protection analysis showed that the oxytocin transgene was transcribed from the normal functional promoter in the Sertoli cells of the seminiferous tubules in a developmentally regulated manner. Immunohistochemistry indicated that both oxytocin and neurophysin epitopes were expressed together in the Sertoli cells at stages I-V and X-XII of the cycle of the seminiferous epithelium. Furthermore, analysis with high-performance liquid chromatography showed that there was a tenfold increase in the amount of amidated oxytocin present in testicular extracts from the transgenic mice. However, there appeared to be no detectable effect of this overproduction of hormone on testicular morphology or fertility parameters. A significant decrease by 50% was detected only in the levels of intratesticular testosterone and dihydrotestosterone. The results point to a local paracrine role for oxytocin in the modulation of Leydig cell function.
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PMID:Over-expression of oxytocin in the testes of a transgenic mouse model. 751 Nov 54

The peptide hormone oxytocin is produced both in the hypothalamus and in certain peripheral organs. The extent of extra-hypothalamic hormone synthesis in the pregnant cow has not previously been examined. In this study we have analyzed different tissues from the pregnant bovine reproductive tract and corpus luteum for the presence of mRNA encoding the oxytocin peptide as well as the oxytocin receptor. In uterine tissues oxytocin mRNA could only be detected sporadically with the help of a reverse transcription-polymerase chain reaction method, implying only very low levels of expression. The caruncles showed a consistently low level of oxytocin gene expression, which appeared up-regulated at term. However, in the corpus luteum there was a significant level of oxytocin gene expression at term, particularly following the onset of labor. The transcript levels were sufficiently high to be measurable by both RNase protection assay and by Northern hybridization; these levels imply a rescue of the oxytocin gene expression seen in the corpora lutea of cyclic and early pregnant cows. At the peptide level this expression was confirmed by immunohistochemistry. A sensitive RNase protection assay was developed to detect transcripts encoding the oxytocin receptor. Transcripts were detected in most uterine tissues, including the caruncles, with highest levels in the endometrium and myometrium at term. No transcripts could be detected in the corpus luteum at any stage of pregnancy, nor in the amnion. The results suggest the possibility of local, paracrine effects of oxytocin within the uterus of the pregnant cow. The rescue of luteal oxytocin at term could act to supplement the circulating hormone of pituitary origin.
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PMID:Oxytocin and oxytocin receptor gene expression in the reproductive tract of the pregnant cow: rescue of luteal oxytocin production at term. 757 79

Northern blot hybridization showed that bovine and sheep testis, unlike testes from other mammals, contain moderate levels of an apparently normal oxytocin gene transcript. In situ hybridization localized this mRNA to within the seminiferous tubules, possibly in the Sertoli cells. Conflicting with this result, immunohistochemistry showed that both oxytocin and the syngeneic neurophysin I epitopes are both clearly restricted to the Leydig cells, being expressed here at a low level. Since illegitimate transcription from spurious start sites can lead to a lack of translation product, the integrity of the major ruminant testicular transcripts of the oxytocin gene was checked using differential hybridization. RNase protection and multiple polymerase chain reaction assays. All tests showed the transcripts to have a normal, translatable composition and to be transcribed from the conventional 5' initiation site. Therefore, the block in oxytocin gene expression within the tubules is probably due to a lesion at the post-transcriptional level. The low level peptide expression in the Leydig cells can probably be attributed to the presence of functional transcripts in these cells, which are below the level of significant detection for the in situ hybridization assay.
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PMID:Post-transcriptional block in oxytocin gene expression within the seminiferous tubules of the bovine testis. 813 53

3' phosphorothioate modified sense or antisense oligonucleotides to oxytocin transcripts were used for in vivo targeting of oxytocin (OT) neurons in the rat hypothalamus. Intracerebroventricular injections of antisense probe resulted in a loss of systemic OT. However, abundant immunoreactive OT as well as oxytocin mRNA hybridization signal was visualized in the hypothalamo neurohypophysial system (HNS) of these animals. RT-PCR of hypothalamic homogenates revealed clearly detectable amounts of cytoplasmic OT mRNA in spite of sense or antisense treatment. Immunostaining with an antibody to DNA-RNA triple helix resulted in cytoplasmic reaction product in the HNS in the antisense group, which was not found when tissue sections had been pretreated with RNase. Animals injected with the sense probe showed a less pronounced but significant loss of systemic OT while immunoreactivity for this peptide in the posterior lobe seemed to be unaffected. RT-PCR of OT encoding mRNA extracted from sense injected rats indicated that these transcripts were of smaller size than samples from antisense treated animals or controls. Immunostaining with the triple helix antibody revealed distinct immunoreactive dots in cellular nuclei throughout the brain in the sense group. Our findings suggest that sense and antisense probes may not readily be employed as "functional antagonists" since peptidergic neurons are probably capable of responding in various ways to the treatment. RNase H may be less important in hypothalamic neurons as commonly suggested. Targeted transcripts are likely to form complexes which may somehow interact with secretion. Triple helix formation in the nucleus may not be able to induce an efficient transcriptional arrest. Although endocrine and behavioral changes observed in antisense treated animals seem to confirm the hypothesis that a selective translational "knock out" can be achieved with in vivo hybridization strategies, the actual underlying molecular events are far from being understood. On the other hand, sense or antisense strategies may provide valuable insights into molecular and cellular events associated with neurosecretion.
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PMID:Sense- and antisense-targeting of oxytocinergic systems in the rat hypothalamus. 871 52

Oxytocin (OT) receptor (OTR) concentrations were determined in the cervix of nonpregnant cows on cycle Days 0, 3, 7-8, 17, and 19 (n = 3-4 cows each day); [3H]OT was used as the labeled ligand. Mucosal and muscle layers of the cervix were also analyzed separately for both ligand binding and expression of the OTR gene using a newly developed RNase protection assay (RAP). Cellular localization of OTR protein was determined by immunohistochemistry. All regions of cervix from cows at estrus had high concentrations of OTR; in the luteal phase, all were sharply down-regulated. At estrus the mucosal layer had about 30-fold higher concentrations than the muscle layer. OTR mRNA was readily detected by RAP in the mucosa from estrous cows, while much weaker signals were found in the muscle. On Days 7-17, the OTR mRNA signals in both mucosa and muscle were very faint or nondetectable. Thus, there was a good correlation between ligand binding and mRNA expression, which suggests that OTR concentrations are mainly regulated at the transcriptional level. The epithelial cells at the luminal surface of the mucosa were the principal site of immunoreactive OTR; muscle cells showed significantly weaker signals. Previously, OT was found to stimulate prostaglandin (PG) E2 output in vitro in bovine cervical tissues. Since PGE2 is capable of softening the cervix, our findings suggest that OT may have a novel physiological function to cause softening of the bovine cervix mediated by the release of PGE2.
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PMID:Oxytocin receptors in bovine cervix: distribution and gene expression during the estrous cycle. 883 94


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