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)

The concentration of MSH in serum after estrogen or progesterone injection into gonadectomized rats was measured by a biological assay. Undetectable serum MSH values were found in long-term ovariectomized (OVX) rats. After a single injection of 10 microgram estradiol benzoate (EB) serum MSH exhibited a circadiam rhythm with high levels in the afternoon, while values in the morning were negative. This effect occurred for 4 days following the injection. Progesterone injection into spayed rats also resulted in an increase of serum MSH concentration, but in contrast to the changes observed after EB treatment high values were found in the morning for 3 consecutive days. Afternoon MSH levels were low but measurable. The effect of these steroids on the activity of the hypothalamic enzymes which yielded MIF or MRF upon incubation with oxytocin (OXT) was also studied. Enzymatic activity of both systems was undetectable in OVX rats and was evident after EB treatment. Progesterone increased only the activity of the system which yields MRF. In castrated male rats estrogen elevated baseline MSH levels but a circadian rhythm was not observed, whereas progesterone had no effect. These observations demonstrate a sex difference on steroid-induced MSH release.
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PMID:Effect of estrogen and progesterone on the release of MSH in gonadectomized rats. 2 14

The reaction products of plasma enzyme degradation of TRH were identified by thin layer chromatography. The enzyme in normal rat plasma yields proline and pGlu-His as major reaction products. High concentrations of proline decrease peptide cleavage, resulting in greater amounts of acid TRH. The apparent Km of the enzyme is 4.1 X 10(-6) M. LHRH and neurotensin are competitive inhibitors with Ki of 5 X 10(-6) M and 1.5 X 10(-5) M, respectively. Somatostatin, MIF, oxytocin, arg-vasopressin, arg-vasotocin, neurophysin II and glucagon do not compete; and pGlu-His-Pro-OH, Glu-His-Pro-OH, pGlu-His, His-Pro-NH2, and Pro-NH2 do not affect enzyme activity. These data suggest that the substrated requires pGlu and a terminal or internal amide to complex with the enzyme. The enzyme is markedly inhibited by Cu++, Bal, benzamadine, p-(chloromercuri)-benzoic acid, moderately affected by EDTA and puromycin, and unaffected by mercaptoethanol. TSH does not affect enzyme activity while LH inhibits it moderately at high concentrations (300-600 pg/ml).
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PMID:Characteristics of the plasma TRH-degrading enzyme. 81 19

The transport of 125I-oxytocin from brain to blood was investigated in mice after intraventricular injection of radioactively labeled oxytocin with or without unlabeled candidate inhibitors. Residual radioactivity in the brain detected after decapitation was the principal determinant of transport activity. The half-time disappearance from the central nervous system of labeled oxytocin was 19.1 min. Inhibition by 10 nmol/mouse of oxytocin showed a saturable component to transport. A 10-nmol dose of tyrosine-melanocyte-stimulating hormone release inhibiting factor (Tyr-MIF-1) and pressinamide also significantly inhibited transport of labeled oxytocin (p less than 0.05). There was no inhibition of the system by a 10-nmol dose of tyrosine, iodotyrosine, MIF-1, or arginine vasopressin. Studies performed with 125I-oxytocin injected simultaneously with 131I-Tyr-MIF-1 with or without unlabeled oxytocin or Tyr-MIF-1 were consistent with both peptides being transported by the previously described peptide transport system-1 (PTS-1). Pretreatment with aluminum (100 mg/kg of elemental aluminum given 60-90 min before intraventricular injection), previously shown to inhibit PTS-1 and some other transport systems, inhibited the transport of labeled oxytocin. Radioactivity collected from the blood after intraventricular injection of 125I-oxytocin eluted on HPLC at the same position as the labeled oxytocin standard and differently from tyrosine, Tyr-MIF-1, MIF-1 and tocinamide. It is concluded that a saturable system exists for the transport of intact oxytocin from brain to blood which appears to be the previously described PTS-1.
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PMID:Carrier-mediated transport of labeled oxytocin from brain to blood. 167 95

The daily pretreatment of rats with oxytocin (OXY) or MIF-I prior to ethanol (Et-OH) administration markedly altered the alcohol tolerance when tested on the fifth day of treatment. OXY (800 and 2400 nmole/kg SC) and MIF (800 nmole/kg SC) inhibited the development of tolerance to the hypnotic effect of Et-OH. MIF at this dose also inhibited the tolerance to the hypothermic effect. Only OXY in the dose of 800 nmole/kg suppressed hypothermia in an acute experiment with Et-OH and produced by itself hypothermia after acute administration (2400 nmole/kg). The tolerance to this last effect developed after four days of peptide treatment. The results indicate that OXY and MIF-I can influence the processes of development of tolerance to some central depressive effects of Et-OH in rats.
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PMID:The effect of oxytocin and fragment (MIF-I) on the development of tolerance to hypothermic and hypnotic action of ethanol in the rat. 285 73

Both in the behavioral despair test and in the learned helplessness test, the antidepressant-like activity of oxytocin (0.500 mg/Kg i.p.) was prevented by the administration of a protease inhibitor (EACA, 400 mg/Kg i.p.; pepstatin, 0.1 mg/Kg i.p.). On the other hand, the linear tripeptide tail of oxytocin, MIF-1, was inactive in the behavioral despair test, and less active than oxytocin in the learned helplessness test. We conclude that the antidepressant activity of oxytocin is due to its cleavage to some smaller fragment(s) different from MIF-1.
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PMID:Influence of protease inhibitors on the antidepressant activity of oxytocin. 289 Oct 75

A tabular synopsis is presented for articles concerned with the effects of peptides on the central nervous system that appeared in the journal Peptides from 1980-1985. A table arranged alphabetically by peptide and one arranged by effects, both listing routes of injection, species, direction of change, and qualifying notes, provides easy cross-referencing of peptides and their effects. Over 80 peptides and over 135 effects are listed. The list of peptides includes, but is not limited to: ACTH, angiotensin, bombesin, bradykinin, calcitonin, casomorphin, CCK, ceruletide, CGRP, CRF, dermorphin, DSIP, dynorphin, endorphins, enkephalins, GRF, gastrin, LHRH, litorin, metkephamid, MIF-l, motilin, MSH, NPY, NT, oxytocin, ranatensin, sauvagine, substances P and K, somatostatin, TRH, VIP, vasopressin, and vasotocin. The list of effects includes, but is not limited to: aggression, alcohol, analgesia, attention, avoidance, behavior, cardiovascular regulation, catalepsy, conditioned behavior, convulsions, dopamine binding and metabolism, discrimination, drinking, EEG, exploration, feeding, fever, gastric secretion, GI motility, grooming, learning, locomotor behavior, mating, memory, neuronal activity, open field, operant behavior, rearing, respiration, satiety, scratching, seizure, sleep, stereotypy, temperature, thermoregulation and tolerance.
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PMID:Central nervous system effects of peptides, 1980-1985: a cross-listing of peptides and their central actions from the first six years of the journal Peptides. 353 8

A brain to blood carrier-mediated transport system for arginine vasopressin (AVP) was investigated in mice after intraventricular injection of iodinated AVP and varying amounts of unlabeled material or candidate inhibitors. Residual activity in the brain detected after decapitation was used as the main determinant of transport activity. The half-time disappearance of iodinated AVP from the brain was 12.4 min, the Vmax was 1.41 nmol/g-min, and the apparent Km was 28.7 nmol/g. A 30-nmol dose of AVP, mesotocin, arginine vasotocin, pressinoic amide, pressinoic acid, tocinoic acid, and lysine vasotocin, but not oxytocin, lysine vasopressin, AVP free acid, tocinoic amide, Tyr-MIF-1, or cyclo Leu-Gly, significantly (P less than 0.05) inhibited the transport of iodinated AVP out of the brain. The 30 nmol dose of AVP had no effect on the transport of iodide or iodotyrosine out of the brain. High-performance liquid chromatography showed that 59.2% of the radioactivity found in the blood 2 min after an i.c.v. injection of labeled AVP eluted at the same position as labeled AVP compared with 68.8% of radioactivity eluting at that position after material was infused i.v. for 2 min. This indicates that intact peptide is transported across the blood-brain barrier and that most of the degradation of AVP occurs during circulation in the blood. Calculations based on the appearance of radioactivity in the periphery showed that 56.2% of the material injected centrally would have been transported into the periphery by 10 min. This appearance of material in the periphery was inhibited by the simultaneous injection of an excess of unlabeled peptide. Water loading significantly decreased the brain to blood transport rate of AVP by 40%. It is concluded that a saturable system exists for brain to blood transport of AVP and some structurally similar peptides.
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PMID:Carrier-mediated transport of vasopressin across the blood-brain barrier of the mouse. 369 15

The hypothalamic peptide MIF-1 (Pro-Leu-Gly-NH2) was coupled to thyroglobulin and injected into rabbits. The resulting antiserum reacted with the tetrapeptide Tyr-MIF-1 to a greater extent than with the tripeptide MIF-1, presumably because of a better conformation for antibody binding. By radioimmunoassay (RIA), immunoreactive MIF-1/Tyr-MIF-1-like material was found in the pineal gland of each of the 100 rats examined. The tendencies for slightly higher levels in pineals obtained from rats kept in constant darkness for two weeks, from rats in a normal light cycle decapitated at noon, or from rats which had been hypophysectomized were not statistically significant. Gel filtration of pineal extracts on a column of Sephadex G-10 revealed that by RIA one immunoreactive peak eluted near MIF-1 and oxytocin, and another peak near Tyr-MIF-1. The results suggest the presence in pineal tissue of an MIF-1-like material as well as a novel peptide containing Tyr-Pro-Leu-Gly-NH2 or a closely related structure for which oxytocin is unlikely to be the precursor.
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PMID:Radioimmunoassay of MIF-1/Tyr-MIF-1-like material in rat pineal. 611 Oct 86

Levels of N-Tyr-MIF-1-like immunoreactivity were measured in rat brain by radioimmunoassay (RIA). Although the highest levels were found in the pineal and hypothalamus, the striatum and thalamus also contained significantly more immunoreactivity than the other parts of the brain. Since oxytocin cross-reacts 5.4% with the antibody for N-Tyr-MIF-1, oxytocin-like immunoreactivity was also measured by RIA, but could not account for the levels of radioimmunoassayable N-Tyr-MIF-1 found in these experiments. There was a significant increase in N-Tyr-MIF-1-like immunoreactivity after pinealectomy, a tendency for a decrease after stress, but essentially no change after hypophysectomy. A diurnal rhythm was observed with the highest levels at night and lowest levels during the day. The results demonstrate the presence in brain tissue of a novel immunoreactive peptide, the levels of which can be altered by neuroendocrine manipulations.
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PMID:Radioimmunoassayable N-Tyr-MIF-1-like activity in rat brain is increased by pinealectomy. 612 31

A study was made of the effect of the low-molecular neuropeptides, leu- and met-enkephalins, thyroliberin (TRH), the C-end tripeptides, gastrin (MAF) and oxytocin (MIF) on the content of biogenic monoamines and their metabolites and on the production of humoral antibodies to sheep red blood cells. The action of the peptides enumerated was compared to that of the peptide immunostimulant, tuftsin. All the peptides (upon intraventricular administration) with the exception of tuftsin affect the content of brain biogenic monoamines or their metabolites. Moreover, upon intravenous injection the neuropeptides under study except met-enkephalin exert a modulating action on the immune response pattern and intensity Leu-enkephalin, MIF and MAF have immunostimulant activity similar to tuftsin. TRH given in high doses (100 and 150 mg/kg) provokes almost a two-fold decrease in the antibody titer. This peptide has an immunosuppressant effect when administered both intravenously and intracisternally. It is suggested that neuro- and immunomodulator effects have much in common at the level of cell receptors.
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PMID:[Comparison of the neuro- and immunomodulator properties of low-molecular neuropeptides]. 612 28


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