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)

Uterine tissue samples were collected from 47 ewes at various stages of the oestrous cycle and early pregnancy (until day 21) and during seasonal anoestrus. Cryostat sections were immunostained to determine the localization of oestradiol and progesterone receptors using specific monoclonal antibodies. Oxytocin receptors were localized by autoradiography in sections from the same ewes using the 125I-labelled oxytocin antagonist d(CH2)5[Tyr(Me)2,Thr4,Tyr-NH2(9)]- vasotocin. Plasma progesterone measurements were made during the preceding cycle up to the time of slaughter. Oestradiol receptor concentrations were maximal in all regions of the tract at oestrus. Immunostaining of the luminal epithelium, superficial glandular epithelium, stroma and myometrium decreased in the early luteal phase but was maintained for longer in the deep glands. Progesterone receptor immunostaining in the luminal epithelium and superficial glands developed in the early luteal phase (days 1-2) with a somewhat later appearance in the deep glands (days 5-7). Progesterone receptor concentrations in the stroma and myometrium also reached a maximum in the early luteal phase. Myometrial staining was clearly maintained throughout the luteal phase whereas stromal staining was variable between ewes. For both oestradiol and progesterone receptors no differences were apparent between pregnant and non-pregnant ewes between days 2 and 12, but pregnant ewes did not show the general increases in oestradiol receptor staining associated with luteolysis on days 14-15. Oxytocin receptors first developed in the luminal epithelium of non-pregnant ewes on day 14 of the cycle and spread to the superficial glands, caruncular stroma, deep glands and myometrium at oestrus before decreasing in reverse order on days 1-2. Specific binding was not detectable on days 5-12 of the cycle or on days 14 or 21 of pregnancy. The appearance of oxytocin receptors in the luminal epithelium on day 14 preceded that of both the oestradiol and progesterone receptors in the epithelial cells and the fall in plasma progesterone. It was followed by the development of oestradiol and oxytocin receptors in the superficial glands, deep glands, caruncular stroma and myometrium, with the two receptor populations showing a significant positive association in these tissues. The loss of oxytocin receptors in all regions occurred as plasma progesterone levels were increasing, but the association between these two variables was only significant in the superficial glands. The development of progesterone receptors in different tissues could not be explained on the basis of either oestradiol receptor content or plasma progesterone.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Localization of oestradiol, progesterone and oxytocin receptors in the uterus during the oestrous cycle and early pregnancy of the ewe. 827 21

The distributions of oxytocin (OT) and the oxytocin receptor (OTR) have been characterised in preovulatory follicles of the marmoset monkey and are described in relation to the process of luteinisation using a combination of in vitro and in vivo techniques, including immunohistochemistry and granulosa cell culture. Ovaries were collected in the periovulatory phase before and 22h after exogenous gonadotropin (hCG) treatment, but prior to ovulation. Before hCG treatment, OT immunoreactivity (OT-ir) was found mostly in granulosa cells of antral follicles, especially in the layers nearest the antrum. In contrast, oxytocin receptor immunoreactivity (OTR-ir) was observed principally in basal granulosa cells of antral follicles. Progesterone receptor (PR) and 3 beta hydroxysteroid dehydrogenase (3 beta HSD), markers for luteinisation, were negative for all ovarian tissues collected before hCG treatment. After hCG treatment, almost all granulosa cell layers in antral follicles stained positively for both OT-ir and OTR-ir, most prominently in preovulatory follicles and especially in the cumulus oophorus. This increase in staining was associated with an induction of PR and 3 beta HSD activity in the granulosa cells of preovulatory follicles. OT production by granulosa cells in culture was stimulated by the addition of hCG, but only in cultures derived from preovulatory follicles; whereas FSH was without any effect. Addition of extrinsic OT to the cultures elicited an increase in progesterone production only for the granulosa cells derived from preovulatory follicles. Together, the results of the in vivo and in vitro studies point to an involvement of OT in the process of leuteinisation in the marmoset monkey.
 ...
PMID:Oxytocin: a follicular luteinisation factor in the marmoset monkey. 871 8

Luteinization is a complex differentiation process involving the interaction of extrinsic and intraovarian factors. The aim of this study was to examine the components of an intraovarian oxytocin (OT) system during the periovulatory period in the marmoset monkey, as well as the possible relationship of these components to other factors involved in the luteinization process, using immunohistochemistry and cell culture techniques. Ovaries were collected on Day 7 of the follicular phase (before the endogenous LH surge) and on Day 8 (22 h after an exogenous hCG application, but before ovulation). Before the endogenous LH increase, OT immunoreactivity was detectable at low levels in most antral follicles, where its presence was confined to antral granulosa cell (GC) layers. In contrast, immunoreactivity for the OT receptor (OTR) was localized primarily in the basal GC layer. After application of exogenous hCG, there was a marked enhancement in both the staining intensity and the number of cells positive for OT and the OTR in all GC layers of antral follicles, especially in the preovulatory follicle. Progesterone receptor and 3beta-hydroxysteroid dehydrogenase activity in GC were clearly present only when follicles were obtained after gonadotropin stimulation. Secretion of authentic OT was demonstrated from cultured GC obtained before the LH surge, with highest amounts in cells cultured from preovulatory as opposed to smaller antral follicles. OT production could be stimulated by the application of hCG to the GC cultured from preovulatory follicles, whereas the gonadotropin was without effect on GC from small follicles. FSH had no effect on OT production by GC from either follicle type. Application of OT to the cultures caused an increase in progesterone production by GC from large preovulatory follicles but was without effect on steroidogenesis by cells from small antral follicles. These results describing the presence and distribution of OT and OTR and their modulation by hCG, as well as the luteotrophic effect of OT in cultured GC from preovulatory follicles, implicate OT as a paracrine mediator in the luteinization process in the primate ovary.
 ...
PMID:A local oxytocin system is part of the luteinization process in the preovulatory follicle of the marmoset monkey (Callithrix jacchus). 920 75

Although it is well known that progesterone alters uterine contractility and plays an important role in maintenance of pregnancy, the biochemical mechanisms by which progesterone alters uterine contractility in human gestation are less clear. In this investigation we sought to identify progesterone-induced adaptations in human myometrial smooth muscle cells that may alter Ca2+ signaling in response to contractile agents. Cells were treated with vehicle or the progesterone analog medroxyprogesterone acetate (MPA) for 5 days, and intracellular free Ca2+ concentration ([Ca2+]i) was quantified after treatment with oxytocin (OX) or endothelin (ET)-1. OX- and ET-1-induced increases in [Ca2+]i were significantly attenuated in cells pretreated with MPA in a dose-dependent manner. Progesterone receptor antagonists prevented the attenuated Ca2+ transients induced by MPA. ETA and ETB receptor subtypes were expressed in myometrial cells, and treatment with MPA resulted in significant downregulation of ETA and ETB receptor binding. MPA did not alter ionomycin-stimulated increases in [Ca2+]i and had no effect on inositol trisphosphate-dependent or -independent release of Ca2+ from internal Ca2+ stores. We conclude that adaptations of Ca2+ homeostasis in myometrial cells during pregnancy may include progesterone-induced modification of receptor-mediated increases in [Ca2+]i.
 ...
PMID:Effect of progesterone on intracellular Ca2+ homeostasis in human myometrial smooth muscle cells. 995 Jul 65

This study examined the expression patterns of oxytocin and steroid receptors in the bovine endometrium during the oestrous cycle and early pregnancy to elucidate their respective roles in the regulation of luteolysis and the maternal recognition of pregnancy. In Expt 1, uterine biopsies were collected from four cows throughout three oestrous cycles each, to provide daily samples. In Expt 2, uterine tissue was collected on days 12, 14, 16 and 18 of the oestrous cycle (n = 20) or early pregnancy (n = 16). Oxytocin receptor, oestrogen receptor alpha and progesterone receptor mRNAs were localized by in situ hybridization, and localization of oestrogen receptor and progesterone receptor was confirmed by immunocytochemistry. All three receptors showed time- and cell-specific expression patterns. Oestrogen receptor alpha increased in all regions at oestrus but high concentrations were also found in the luminal epithelium during the mid-luteal phase and in the deep glands throughout the oestrous cycle. Progesterone receptor expression was higher in the stroma than it was in the types of epithelial cell, and increased expression was observed at oestrus and during the early luteal phase. The cyclical upregulation of oxytocin receptors in the luminal epithelium on about day 16 was not related to preceding changes in the endometrial expression of either oestradiol alpha or progesterone receptors. During early pregnancy, oxytocin receptor expression was suppressed. Oestrogen receptor a concentrations increased in the non-pregnant cows and decreased in the pregnant cows between days 16 and 18, but these changes followed rather than preceded the upregulation of oxytocin receptors in the non-pregnant cows. It is concluded that the initial upregulation of oxytocin receptors in the luminal epithelium, which triggers luteolysis, is not associated directly with changes in expression of oestrogen receptor alpha.
 ...
PMID:Expression of oxytocin, oestrogen and progesterone receptors in uterine biopsy samples throughout the oestrous cycle and early pregnancy in cows. 1173 92

In bovines characterization of biochemical and molecular determinants of the dominant follicle before and during different time intervals after gonadotrophin surge requires precise identification of the dominant follicle from a follicular wave. The objectives of the present study were to standardize an experimental model in buffalo cows for accurately identifying the dominant follicle of the first wave of follicular growth and characterize changes in follicular fluid hormone concentrations as well as expression patterns of various genes associated with the process of ovulation. From the day of estrus (day 0), animals were subjected to blood sampling and ultrasonography for monitoring circulating progesterone levels and follicular growth. On day 7 of the cycle, animals were administered a PGF(2alpha) analogue (Tiaprost Trometamol, 750 microg i.m.) followed by an injection of hCG (2000 IU i.m.) 36 h later. Circulating progesterone levels progressively increased from day 1 of the cycle to 2.26+/-0.17 ng/ml on day 7 of the cycle, but declined significantly after PGF(2alpha) injection. A progressive increase in the size of the dominant follicle was observed by ultrasonography. The follicular fluid estradiol and progesterone concentrations in the dominant follicle were 600+/-16.7 and 38+/-7.6 ng/ml, respectively, before hCG injection and the concentration of estradiol decreased to 125.8+/-25.26 ng/ml, but concentration of progesterone increased to 195+/-24.6 ng/ml, 24h post-hCG injection. Inh-alpha and Cyp19A1 expressions in granulosa cells were maximal in the dominant follicle and declined in response to hCG treatment. Progesterone receptor, oxytocin and cycloxygenase-2 expressions in granulosa cells, regarded as markers of ovulation, were maximal at 24h post-hCG. The expressions of genes belonging to the super family of proteases were also examined; Cathepsin L expression decreased, while ADAMTS 3 and 5 expressions increased 24h post-hCG treatment. The results of the current study indicate that sequential treatments of PGF(2alpha) and hCG during early estrous cycle in the buffalo cow leads to follicular growth that culminates in ovulation. The model system reported in the present study would be valuable for examining temporo-spatial changes in the periovulatory follicle immediately before and after the onset of gonadotrophin surge.
 ...
PMID:Standardization and validation of an induced ovulation model system in buffalo cows: Characterization of gene expression changes in the periovulatory follicle. 1877 64

There is no approved medical therapy for adenomyosis and limited evidence to guide treatments in part due to the complexity of nonhistologic diagnosis and the prevalence of concomitant gynecologic conditions. Most available evidence focuses on the treatment of heavy menstrual bleeding, painful menses, and pelvic pain. Data evaluating fertility outcomes, sexual function, and quality of life following treatment are lacking. Additionally, there is no disease-specific measure of quality of life for adenomyosis. The levonorgestrel-releasing intrauterine system appears to be the most effective first-line therapy based on efficacy compared with oral agents, maintenance of steady-state hormonal levels, and contraceptive benefit. In areas where it is marketed, the progestin dienogest appears superior to combined oral contraceptives. Long-acting gonadotropin-releasing hormone agonists are effective and should be considered second-line therapy but are limited by hypogonadal effects. Additional data regarding oral gonadotropin-releasing hormone antagonists are required. While aromatase inhibitors demonstrate improvement in heavy menstrual bleeding and pelvic pain, further research is needed to determine their role in the management of adenomyosis. Progesterone receptor modulators may have a role for this disease if released again to market with appropriate safety parameters. Finally, modulation of prolactin and/or oxytocin may provide novel nonsteroidal treatment options.
 ...
PMID:Current and Future Medical Therapies for Adenomyosis. 3312 17