Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We studied the effects of chronic replacement with arginine vasopressin (AVP) or 1-desamino-D-arginine vasopressin (DDAVP), as well as acute replacement with AVP or DDAVP, on the responsiveness of oxytocin (OT) neurons as indexed by plasma oxytocin-associated neurophysin concentration [( OT-RNP]) during acute salt loading in conscious, chronically catheterized homozygous Brattleboro (DI) rats. Salt loading was carried out on days 5 and 12 of AVP (3,000 ng/day) or DDAVP (50 ng/day) treatment or 60 min after intraperitoneal injection of 1 microgram AVP or 25 ng DDAVP. All vasopressin treatments did not significantly alter the basal [OT-RNP]. In response to infusion of 18% saline, there were corresponding significant increases in plasma osmolality (Posmol) and [OT-RNP] in all animals. The increases in [OT-RNP] in vasopressin-treated DI rats were markedly reduced compared with those observed earlier for untreated DI animals despite similar rises in Posmol. The slopes of the relationship between delta [OT-RNP] and delta Posmol were 9.0 and 9.8 fmol X ml-1 X mosmol-1 X kg for chronically AVP-treated DI rats, 8.9, and 8.8 fmol X ml-1 X mosmol-1 X kg for chronically DDAVP-treated DI animals, 10.7 fmol X ml-1 X mosmol-1 X kg for acutely AVP-treated DI rats, and 8.3 fmol X ml-1 X mosmol-1 X kg for acutely DDAVP-treated animals compared with that of 34.9 fmol X ml-1 X mosmol-1 X kg for untreated DI rats.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Exogenous vasopressin modulates activity of oxytocin neurons in homozygous Brattleboro rats. 377 64

Endogenous oxytocin released into the brain at parturition may stimulate the onset of maternal behaviour. In this study an attempt was made to block spontaneous maternal behaviour following natural delivery in Wistar rats by the injection of an antagonist of oxytocin into the cerebral ventricles. The analogue antagonist, d(CH2)5-8-ornithine-vasotocin, was administered by injection into a chronically implanted cannula in the right lateral ventricle at hourly intervals, beginning immediately after the expulsion of the first pup. The antagonist did not interfere with the normal progress of parturition or birth-related behaviours. After delivery of the last pup, mothers rested for 40 min in the test cage with the pups having been removed. Four pups and standard nesting material were then presented. Latency to pup carrying and duration of pup manipulation, nest building, and time spent on the nest with the pups, as well as duration of autogrooming and general activity were determined. Saline-injected controls started gathering the pups immediately and usually showed all elements of maternal behaviour within 10 min. Antagonist-treated mothers showed a marked delay in the onset of pup grouping and other maternal behaviours. At the end of 1 h, two out of six mothers had not yet picked up a single infant. Pups left overnight with their mothers were gathered into the nest and suckled, and no long-term effects of the antagonist were evident on retesting. The effectiveness of oxytocin antagonist in suppressing the rapid onset of post-partum maternal behaviour supports the hypothesis that centrally released oxytocin is involved in this process.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Inhibition of post-partum maternal behaviour in the rat by injecting an oxytocin antagonist into the cerebral ventricles. 381 39

160 women with uteri at 10-20 weeks gestation were treated with either PG(prostaglandin)F2alpha or saline solution followed by oxytocin to effect an abortion. 80 women were in each treatment group. The distribution of the patients according to age, parity, and gestation duration is tabulated. PGF2alpha was administered extraovularly in a concentration of .1 mg/ml with .7 mg being injected in the operating theater and nurses administering the rest based on response to previous injections. Administration continued for up to 30 hours. Saline was given in a volume in ml dependent on the duration of pregnancy multiplied by a factor of 10. Subcutaneous injections of oxytocin were given on subsequent days to speed the abortion. 85% of the PG patients successfully aborted without surgical dilatation of the cervix. The average dosage of PG required was 7.5 mg in 11 instillations. Side effects and complications in the PG group were minimal. 1 instillation of saline followed by 2 days of oxytocin were required to effect a 79% abortion rate in the saline group. Although the number of patients requiring surgical dilatation was the same for both groups, the procedure was much less time-consuming for the PG group. The complication rate was 26% for the saline group as compared to 14% for the PG group. The PG group required a shorter hospital stay.
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PMID:Induction of therapeutic abortion using either extra-amniotic prostaglandin F-2-alpha or hypertonic saline followed by oxytocin. 484 14

The treatment of infertility is discussed and illustrated by a case study. A 24 year-old woman and her husband were classified as "normal-fertile" by the usual standard, yet she had failed to conceive. Treatment with estrogen at mid-cycle, tranquilizers, oxytocin, cortisone, hysterogram, and saline hydrotubation had no beneficial effect. However, the administration of 50 mg/day of clomiphene from Days 5-9 of the cycle, followed by frequent sexual intercourse, resulted in pregnancy. Of 170 "normal-fertile" infertile couples, hysterosalpingography was the most successful form of treatment (88 pregnancies). Various other treatments resulted in 40 pregnancies. Saline hydrotubation, clomiphene, cortisol, and sedation were the most effective methods for treating infertility. If other less effective treatments also fail, psychiatric evaluation, culdoscopy, laparoscopy, laparotomy, sperm agglutination studies, or endocrine assays may be in order. The importance of psychological considerations in treating infertile patients is discussed.
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PMID:Case studies in reproduction and sexual adjustment. 581 Jun 54

Using radioimmunoassay (RIA), the content of gastrin-cholecystokinin family peptide immunoreactivity (G-CCK-IR), in the posterointermediate lobe (PIL) of the rat pituitary, has been determined in several experimental conditions. G-CCK-IR levels are significantly higher in males than in females. Salt loading induces a significant decrease of G-CCK-IR in animals of either sex. In males, G-CCK-IR levels are lower than controls 21 days after either castration or daily subcutaneous oestradiol injections. Using immunocytochemistry, G-CCK-IR disappears from the external median eminence 21 days after adrenalectomy. Our results show that, in addition to sex difference, factors affecting the vasopressin and/or oxytocin levels in the posterior pituitary and external median eminence also affect G-CCK-IR in the same regions. Cholecystokinin may therefore be of importance in functions related to these hormones.
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PMID:Cholecystokinin varies in the posterior pituitary and external median eminence of the rat according to factors affecting vasopressin and oxytocin. 685 57

Arginine vasopressin (AVP) and oxytocin (OT) mRNAs are targeted to the axonal compartment of rat hypothalamic magnocellular neurons. Salt-loading results in a considerable rise in hypothalamic and axonal AVP mRNA but only a moderate increase for axonal OT mRNA. Here we report that hypoosmolality gives rise to a rapid decrease of axonal AVP encoding transcripts to undetectable levels after 2 weeks. The levels of OT mRNA in the axonal compartment did not change significantly. In the hypothalamus the mRNA for AVP also decreased. The size of the poly(A) tract of AVP encoding transcripts appeared to be strictly correlated with plasma osmolality. In contrast, the amount and size of OT encoding mRNAs were only moderately or not influenced by hypoosmolar stimuli.
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PMID:Effect of hypoosmolality on the abundance, poly(A) tail length and axonal targeting of arginine vasopressin and oxytocin mRNAs in rat hypothalamic magnocellular neurons. 758 28

Sodium chloride ingestion is stimulated during conditions of sodium deficiency to maintain body fluid and electrolyte balance. Recent studies have indicated that salt appetite in rats is often inversely related to peripheral and central secretion of the hormone oxytocin (OT). We studied the potential role of central OT on salt and water ingestion by treating rats intracerebroventricularly with OT conjugated to the A chain of the plant cytotoxin ricin (rAOT) to produce a chronic selective inactivation of brain cells containing OT-receptive elements. The rats treated with rAOT and control rats treated with the ricin A chain alone were given 5-hr two-bottle (water and 0.5 M NaCl) drinking tests 30 min after they were made hyperosmolar by injections of hypertonic (2M) mannitol solution, which elevated plasma osmolality but reduced plasma Na+ concentration. In the control rats only water intake was stimulated in response to the induced hyperosmolality, but in the rAOT-treated rats hypertonic mannitol caused a robust salt appetite as well as thirst. Analogous results were obtained in rats treated with two different OT-receptor antagonists prior to induction of hyperosmolality with mannitol. In contrast to these results, when hyperosmolality was induced by administration of equivalently hypertonic (1M) NaCl, which elevated both plasma osmolality and plasma Na+ concentration, only water intake but not salt intake was stimulated in both control and OT-receptor antagonist-treated rats. When salt appetite was stimulated by the physiological stimulus of polyethylene glycol-induced hypovolemia, hypertonic mannitol similarly inhibited salt ingestion in control animals but not in rAOT-treated rats, whereas hypertonic NaCl inhibited subsequent salt ingestion in both groups. These results suggest that salt appetite is regulated by both Na(+)- and osmolality-sensing mechanisms in rats. In addition, they indicate that central OT likely mediates a significant component of osmolality-related inhibition of salt appetite but does not appear to be essential for Na(+)-related inhibition of this important homeostatic behavior.
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PMID:Central oxytocin inhibition of salt appetite in rats: evidence for differential sensing of plasma sodium and osmolality. 823 2

Neuroanatomical and physiological evidence indicates that baroreceptors influence hypothalamic vasopressin (VP) and oxytocin (OT) neurons. We evaluated the effects of sinoaortic denervation (SAD) on the molecular and endocrine response to salt loading. Sham-operated or SAD rats were given a 2% NaCl solution to drink for 72 h. A group with limited salt water intake was included as a second control because the denervated rats consumed less salt than the controls. Plasma VP, OT and osmolality and posterior pituitary peptide content were measured. Brains were processed for evaluation of VP and OT mRNA expression using in situ hybridization with computer quantitation. Salt loading produced equivalent increases in plasma VP and OT in the control and SAD groups, however, there was a greater depletion of posterior pituitary peptides in the denervated animals. Salt loading produced significant decreases in pituitary VP and OT in the SAD animals, 69.8 +/- 8.4% and 68.3 +/- 4.0%, respectively. In the control groups, there was no decrease in VP content and a decrease in OT only in the control ad lib group. The peptide mRNA response to salt loading was also altered in the denervated rats. There was a significant increase in the area and intensity of the labeling for OT mRNA in the PVN in the SAD salt group. The control salt rats showed an increase in the SON and the salt-limited group showed no changes. For VP mRNA, the only change noted was in the SON of the salt-loaded SAD animals. These results show that chronic denervation of arterial baroreceptors augments the hypothalamic VP and OT response to salt loading.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Sinoaortic denervation alters the molecular and endocrine responses to salt loading. 836 35

Experiments were performed to evaluate the role of central oxytocin (OT) in the inhibition of salt intake produced by sinoartic denervation (SAD). The effect of OT antisense treatment on 24 h intake of 2% NaCl in SAD and sham-operated (SO) rats was determined. PVN injection of unmodified antisense oligodeoxynucleotides (ODNs) to OT mRNA decreased intake of 2% NaCl in SAD, but not SO rats. Salt consumption was 22 +/- 4 ml after the injection of control ODN as compared to 8 +/- 4 ml after the OT antisense injection (P < 0.05). SAD animals also demonstrated an increased plasma OT response to salt loading, an elevation from 3.2 +/- 0.7 to 6.9 +/- 0.8 pg/ml. In contrast, salt ingestion produced no significant change in plasma OT in the SO group. The increased endocrine response in the SADs occurred even though salt intake was lower in this group. There were no group differences in plasma electrolytes or posterior pituitary OT content. Results show that OT antisense specifically inhibits salt intake in the denervated rat, suggesting that the central oxytocinergic axis stimulates sodium drive in this experimental model.
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PMID:Oxytocin antisense reduces salt intake in the baroreceptor-denervated rat. 858 63

The objective of this research was to determine if ergotamine, an ergopeptine alkaloid isolated from Neotyphodium-infected grasses and associated with toxicoses in livestock, altered plasma concentrations of reproductive hormones in follicular phase heifers and in cows given a progestin implant. In Experiment 1, blood was sampled for 8h from four cycling heifers 2 days after synchronized luteolysis. Heifers were treated with ergotamine tartrate (19microg/kg) i.v. or saline vehicle in a simple cross-over design after 1h of pre-treatment blood sampling. Heifers received oxytocin (100USP units) i.v. 4h after ergotamine or saline treatment. Ergotamine reduced (P<0.01) prolactin concentrations from 1 to 4h post-treatment and increased (P<0.01) 13,14-dihydro-15-keto prostaglandin F2alpha (PGFM) concentrations from 2 to 5h post-treatment. A PGFM response to oxytocin was not detected. In Experiment 2, blood was sampled for 8h from six cycling cows 10 days after receiving a s.c. norgestomet implant. Cows were treated i.v. with ergotamine (20microg/kg) or saline in a simple cross-over design after 1h of pre-treatment blood sampling. Cows received gonadorelin (GnRH, 100microg) i.v. 1h after ergotamine or saline. Cows received oxytocin (100USP units) i.v. 4h after ergotamine or saline treatment. Ergotamine reduced (P<0.01) serum prolactin concentrations by 120min after treatment, with prolactin returning to pre-treatment concentrations by 200min after treatment. Saline-treated cows had lower (P<0.01) prolactin by 280min after treatment. Ergotamine-treated cows had higher (P<0.01) PGFM concentrations compared to saline-treated cows 120-240min after treatments, but the groups exhibited similar increases in PGFM after oxytocin. Plasma LH and FSH concentrations increased to peaks 100-120min after GnRH for both groups. However, the LH response to GnRH was greater (P<0.01) for ergotamine-treated cows. In summary, ergotamine lowered prolactin and elevated PGFM concentrations in follicular phase heifers and cows on norgestomet therapy. Ergotamine increased the LH response to exogenous GnRH in cows with norgestomet implants. These data highlight the potential of ergopeptine alkaloids to affect reproduction through altered endocrine function.
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PMID:Effect of an acute ergotamine challenge on reproductive hormones in follicular phase heifers and progestin-treated cows. 1134 77


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