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)

Rats were made unilaterally pregnant by tying the right oviduct on the day after mating, to compare the oxytocin receptor concentrations in a nondistended, nonpregnant uterine horn with those in a distended, pregnant horn. On day 20, they were subjected to bilateral ovariectomy and indwelling balloons were inserted into both uterine horns. Following ovariectomy, the rats were injected im with either oil, estradiol benzoate (5 micrograms/rat per 24 h), or estradiol and progesterone together. For comparison, intact rats were studied on days 21 and 22, 24 and 48 h after insertion of the indwelling balloons. Spontaneous uterine activity and the response to increasing amounts of oxytocin were recorded 20-24 h and 44-48 h after surgery, following which the uteri were excised and assayed for oxytocin and estrogen receptors. The oxytocin receptor concentrations in the two horns were different on day 20 before the treatments were begun, the distended pregnant horn having a higher concentration per milligram DNA than the nonpregnant horn. The various treatments always changed the oxytocin receptor concentrations in the same direction; estrogen increased and progesterone inhibited the estrogen-induced rise in oxytocin receptor concentrations. In intact rats, the distention-induced increase in oxytocin receptor concentrations present on day 20 disappeared near term, but in the absence of the ovaries distention of the uterus had a significant influence on the myometrial oxytocin receptor concentrations, potentiating the effect of estrogen. Progesterone selectively inhibited the distention-induced increase in oxytocin receptor concentrations without inhibiting the hypertrophic effect of distention in general. A good correlation between oxytocin receptor numbers and tissue responsiveness was observed in all instances. The changes in spontaneous activity induced by the various treatments were distinct from the changes in oxytocin responsiveness. Estrogen exerted a strong inhibitory action on the activity stimulated by hormone withdrawal, while progesterone had no inhibitory effect. The pregnant distended horn always showed more spontaneous activity than the nonpregnant horn. There was an overall significant correlation between nuclear estrogen receptor and oxytocin receptor concentrations per milligram DNA, although the partial correlations were not significant in all groups (oil and progesterone).(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Systemic and local regulation of oxytocin receptors in the rat uterus, and their functional significance. 631 57

The concentrations of arginine vasopressin, oxytocin, and their related neurophysins were compared in many areas of postmortem human brain and spinal cord using specific radioimmunoassays. In the hypothalamus the ratio of vasopressin to oxytocin was approximately 3:1, and in the extrahypothalamic areas of the brain the greatest amount of both peptides was present in the locus coeruleus, and to a lesser extent the periaqueductal grey. Vasopressin only was found in the substantia nigra, and globus pallidus. In the medulla, including the nucleus of the solitary tract, the dorsal nucleus of the vagus, and the nucleus of the spinal tract of the trigeminal nerve, the amount of oxytocin was greater than that of vasopressin. In the spinal cord oxytocin predominated over vasopressin to an even greater extent, and reached particularly high values in certain segments of the intermediolateral grey column and dorsal horn. Estrogen-stimulated and nicotine-stimulated neurophysins (ESN and NSN) were both found in large amounts in those areas of the brain and spinal cord where the concentrations of the nonapeptides were greatest, but when the molar ratios of ESN to oxytocin and NSN to vasopressin were compared there was an excess of ESN.
 ...
PMID:Vasopressin, oxytocin and neurophysins in the human brain and spinal cord. 669 76

Estrogen-stimulated neurophysin (ESN) was determined by radioimmunoassay in three groups of patients with chronic renal failure: predialysis patients, patients on hemodialysis and patients on continuous ambulatory peritoneal dialysis. ESN levels were significantly elevated in all patients. ESN of these patients is undistinguishable from highly purified pituitary ESN. Immunological and physicochemical analyses of ESN in patients with renal failure suggest that the elevated plasma level is due to a failure of renal clearance. In addition, heterogeneity of urinary ESN, revealed by multiple immunoreactive peaks after gel filtration, indicates altered renal metabolism.
 ...
PMID:Estrogen-stimulated neurophysin in chronic renal failure. 683 53

The effect of water deprivation or estrogen treatment on the oxytocin content of rat hypothalamic cells was examined using a quantitative immunohistological technique. Oxytocin-containing cells were visualized using the immunoperoxidase technique of Sternberg and a primary antiserum directed against oxytocin. The optical density of the darkest 3.2 micrometer diameter spot in the cytoplasm of a cell was used as a measure of the oxytocin content of that cell. Water deprivation produced a significant decrease in anti-oxytocin staining in the anterior commissural nucleus of males and females. There was a similar decrease in the paraventricular nucleus of males, but not in the paraventricular nucleus of females or the supraoptic nucleus of either males or females. Estrogen treatment of ovariectomized female rats produced a fall in anti-oxytocin staining in the anterior commissural, but not paraventricular or supraoptic nuclei.
 ...
PMID:Changes in oxytocin content in the magnocellular neurons of the rat hypothalamus following water deprivation or estrogen treatment. Quantitative immunohistological studies. 701 83

RIA for the measurement of oxytocin in human plasma is described. Extraction of oxytocin from larger peptides in plasma used acetone precipitation with a 75% +or- 2 SEM recovery of oxytocin. Nonspecific binding of the assay was less than 4% and the minimum level of detection was 0.2 mcU/tube. No cross-reactivity was noted with neurophysins, arginine, or lysine vasopressin. The mean basal level (+or- SEM) of oxytocin in men was 1.80 +or- 0.07 mcU/ml and was not different in normal women (1.71 +or- 0.07 mcU/ml). Changes in posture had no effect on the levels of oxytocin. Samples obtained every 15 minutes over 4 hours showed no pulsatile secretion of oxytocin. In women chronically receiving estrogen as an oral contraceptive, oxytocin was greater than normal (4.59 +or- 0.51 mcU/ml; P0.01). Estrogen-stimulated neurophysin was also elevated *8.45 +or- 1.99 ng/ml; P0.005). Acute ingestion of estrogen caused an increase in the level of oxytocin in plasma by 12 hours and a concomitant elevation of estrogen-stimulated neurophysin. When the neurophysin was isolated from plasma obtained from a subject after ingestion of estrogen, the neurophysin from plasma comigrated on a polyacrylamide gel with a human pituitary standard of estrogen-stimulated neurophsin. In the studies in which neurophysin was elevated, the correlation between the level of oxytocin and the level of estrogen-stimulated neurophysin in plasma was significant (P0.01). The observation that estrogen administration stimulates the release of oxytocin and estrogen-stimulated neurophysin provides additional evidence that this neurophysin is the oxytocin-neurophysin of man.
 ...
PMID:Oxytocin in human plasma: correlation with neurophysin and stimulation with estrogen. 722 98

For the study on initiation of labor, a highly sensitive and specific radioimmunoassay for oxytocin (OT) was developed. Investigations were performed on the blood levels of OT and neurophysins in women during labor, lactation as well as in umbilical vessels. The blood was assayed for OT and Estrogen Stimulated Neurophysin (ESN), Nicotine Stimulated Neurophysin (NSN) in each specific radioimmunoassay. The mean value of plasma OT levels of women without labor pains (5 minutes interval) ws 217.3 +/- 36.02 (pg/ml, Mean +/- S.E.) whereas the values at 28 to 40 weeks of gestation was much lower than those. At delivery the OT level in maternal plasma was 176.3 30.92 and 207.5 62.90 in the umbilical vein respectively. There was no statistical difference in the level of OT before and after lactation. ESN level was higher during lactation and NSN level showed the similar pattern. At delivery NSN concentration in the umbilical artery was higher than that in the vein. These data suggest that hypothalamo-pituitary function correlate with labor and lactation.
 ...
PMID:[Study on blood levels of oxytocin and neurophysins during labor and lactation (author's transl)]. 724 67

The localization at the cellular level and the regulation by progesterone of the estrogen-sensitive oxytocin binding sites was studied in the rat telencephalon and the hypothalamus by using quantitative film-autoradiography and histoautoradiography. Male rats (castrated or not) and ovariectomized females (estradiol supplemented or not) were used to characterize these sites and to precise their localization. They were detected in the striatal cell bridges, the olfactory tubercle, the principal nucleus of the bed nucleus of the stria terminalis and the medial nucleus of the amygdala of the telencephalon and in the medial preoptic, the ventromedial and the ventral premammillary nuclei of the hypothalamus. Estrogen administration in addition induced expression of oxytocin binding sites in the major island of Calleja, the anterior hypothalamic area and the terete nucleus. The density of the estrogen-sensitive oxytocin binding sites varied during the estrous cycle, but differently in the telencephalon and the hypothalamus. In the telencephalon it peaked at proestrus 9 h and was already decreased at proestrus 21 h, whereas in the hypothalamus it was similarly high at proestrus 9 h and proestrus 21 h, suggesting the intervention of progesterone in the regulation of the hypothalamic estrogen-sensitive oxytocin binding sites.
 ...
PMID:Estrogen-sensitive oxytocin binding sites are differently regulated by progesterone in the telencephalon and the hypothalamus of the rat. 764 70

In situ hybridization techniques were used in the present study to detect hypothalamic expression of the oxytocin receptor (OR) gene. Binding studies have localized OR to various brain regions and have detected a high density of receptors in the ventromedial hypothalamus (VMH), a documented target of estrogen action. This study was designed to compare levels of OR messenger RNA (mRNA) in the VMH of male and female rats and to study the effects of estrogen treatment on mRNA levels in the VMH of female rats. After cloning a rat OR gene from a genomic testes library, a probe was generated for use in in situ hybridization assays to evaluate sex differences in OR mRNA expression in the VMH. In addition, ovariectomized females were treated with estrogen, and VMH OR mRNA expression was compared with that in ovariectomized or intact females. The results of these studies showed that male rats expressed higher levels of OR mRNA in the VMH than females. Estrogen-treated ovariectomized females exhibited significantly greater expression in the VMH than either oil-treated or intact females. These results support binding studies that have shown oxytocin binding in the VMH to be regulated by gonadal steroids and suggest that estrogen may either directly or indirectly regulate transcription of the OR gene.
 ...
PMID:Sex differences in and effects of estrogen on oxytocin receptor messenger ribonucleic acid expression in the ventromedial hypothalamus. 782 41

Basal density and estrogen induction of oxytocin binding sites in limbic and hypothalamic structures of the rat brain were investigated by semi-quantitative autoradiography following chronic administration of dexamethasone or progesterone. The selective oxytocin receptor antagonist d(CH2)5[Tyr(Me)2,Thr4,Tyr-NH2(9)] ornithine-vasotocin was used as a ligand for oxytocin binding sites. Estrogen administration increased ligand binding in all sites investigated. Dexamethasone treatment significantly increased ligand binding in the bed nucleus of the stria terminalis, lateral ventral septum and amygdala to an extent which was comparable to that of estradiol alone. In the hypothalamic ventromedial nucleus, dexamethasone significantly decreased basal levels of oxytocin binding. Estrogen administration subsequent to dexamethasone failed to cause a further increase in oxytocin binding in all structures investigated. Chronic progesterone treatment significantly increased basal oxytocin receptor density in the limbic structures, decreased it in the ventromedial nucleus, and prevented estrogen-induced increases in ligand binding in all areas studied with the exception of the medial preoptic area. These findings demonstrate that, in addition to gonadal steroids, glucocorticoids differentially and site-specifically modulate cerebral oxytocin binding sites. The evidence for glucocorticoid and gestagen influences on oxytocin receptors and their inducibility by estrogen may be relevant to the understanding of mechanisms leading to impairment of oxytocin-related behaviours.
 ...
PMID:Oxytocin binding sites in rat limbic and hypothalamic structures: site-specific modulation by adrenal and gonadal steroids. 830 22

1. The effects of estrogens estradiol (E2, 10(-6)-10(-4) M) and diethylstilbestrol (DES, 10(-6)-10(-4) M) and the antiestrogens nafoxidine (N, 10(-6)-10(-4) M), tamoxifen (T, 10(-6)-6 x 10(-4) M), tamoxifen ethyl bromide (TEB, 10(-4) M) and ICI 164,384 (ICI, 10(-5) M) on tonic contractions induced by oxytocin (2 x 10(-8) M) or vanadate (3 x 10(-4) M) in rat uterus incubated in calcium-free EDTA treated solution have been assayed. 2. E2 and DES relaxed the tonic contraction induced by oxytocin in a dose dependent way (EC50: 1.11 +/- 0.01 x 10(-4) M and 1.5 +/- 0.07 x 10(-5) M). The vanadate-induced contraction only was relaxed with DES (57.62 +/- 2.38% at 10(-3) M). 3. The effect of DES on oxytocin contraction was unmodified by the protein synthesis inhibitor cycloheximide (10 micrograms/ml) and by the cyclooxygenase inhibitor indomethacin (3 x 10(-6) M), but enhanced by the intracellular calcium release inhibitor TMB-8 (10(-5) M). The antiestrogen tamoxifen (3 x 10(-5) M) promotes the relaxing effect of DES. 4. The antiestrogens N, and T, but not ICI, relaxed the oxytocin-induced contraction (EC50: 4.51 +/- 0.43 x 10(-5) M and 2.27 +/- 0.05 x 10(-4) M). TEB (10(-4) M) produces a relaxation of 74.5 +/- 2.11%. The vanadate contraction is also relaxed by T (EC50: 6.03 +/- 0.04 x 10(-4) M). 5. The effect of T on oxytocin contraction was unmodified with cycloheximide or TMB-8 but decreased with indomethacin.
 ...
PMID:Estrogen and antiestrogen non-genomic effect in rat uterus contraction in calcium-free solution. 848 24


<< Previous 1 2 3 4 5 Next >>