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 stimulating effect of different pituitary hormones on longitudinal bone growth was determined with tetracycline as intravital marker in hypophysectomized rats. Growth hormone was found to be the most effective growth stimulating pituitary hormone. At considerably higher doses, thyrotrophic hormone (TSH) and prolactin also showed growth stimulating pituitary hormone. At considerably higher doses, thyrotrophic hormone (TSH) and prolactin also showed growth stimulating activity. TSH exerts its effect via the production of thyroxine, whereas the growth stimulation by prolactin seems to be a direct effect of this hormone, similar to the effect of growth hormone. The LH, FSH, ACTH, MSH, vasopressin and oxytocin preparations did not stimulate longitudinal bone growth.
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PMID:Stimulation of longitudinal bone growth by hypophyseal hormones in the hypophysectomized rat. 19 Aug 39

A sc injection of 2 micrograms arginine vasotocin (AVT) administered every 2 h for a 25-h period starting 1 h after castration of adult male rats caused a 43% reduction (P less than 0.05) in plasma levels of LH compared to diluent-treated castrated controls. In Exp 2, a sc injection of 5 micrograms AVT or diluent was administered to intact or acutely castrated male rats every 3 h for 48 h. After AVT administration, both plasma LH (P less than 0.001) and FSH (P less than 0.05) were significantly reduced, with a concomitant increase in pituitary levels of these gonadotropins. Using the same injection regimen in Exp 3, 250 micrograms melatonin had no effect on plasma or pituitary levels of LH in castrated male rats. In the fourth experiment, neither 1 IU arginine vasopressin nor 1 IU oxytocin had an effect on plasma or pituitary levels of LH, whereas 1 IU of AVT significantly lowered plasma levels of LH (P less than 0.05) and prevented the fall in the pituitary level of this gonadotropin (P less than 0.01) when compared to diluent-treated castrated control rats. Oxytocin (1 IU) significantly inhibited (P less than 0.01) plasma levels of FSH and raised plasma levels of PRL (P less than 0.01) in castrated male rats. No effect on plasma titers of PRL were observed after treatment of castrated rats with AVT in Exp 2 or 4. It is concluded that in acutely castrated male rats, AVT could possibly act either on the hypothalamus and/or the pituitary to affect pituitary and plasma levels of gonadotropins.
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PMID:The effect of subcutaneous injections of melatonin, arginine vasotocin, and related peptides on pituitary and plasma levels of luteinizing hormone, follicle-stimulating hormone, and prolactin in castrated adult male rats. 44 49

1. Membrane potentials have been recorded from cells of seminiferous tubules of rats in vitro using micro-electrodes. The value in 808 impalements was -28-2 +/- 0-3 mV (mean +/- S.E.) at 33 degrees C. 2. Increasing the potassium concentration depolarized the cells, a tenfold increase in concentration causing a depolarization of 16 mV. Removal of sodium from the bathing solution caused a hyperpolarization of 3 mV at a potassium concentration of 5-9 m-equiv/l. Removal of chloride and replacement with impermeant anions had no effect on potential. Removal of calcium from the bathing solution caused a minor but significant depolarization. 3. Ouabain (10-3 M), dinitrophenol (2-5 times 10-4 M) or removal of glucose from the bathing fluid all caused depolarization. The membrane potentials of the cells were sensitive to temperature over the range 10-33 degrees C, the apparent activation energy for the reactions maintaining the potential being approximately 6 kcal/mole. 4. Membrane potentials in seminiferous tubules were independent of age of the animal, were insensitive to previous hypophysectomy and were insensitive to a number of hormones (FSH, LH, HCG, oxytocin). In high concentration prostaglandin E1 caused depolarization. 5. Acetazoleamide (4 times 10-5 M) caused a rapid, but reversible, depolarization of the tubular cells. This was also true in conditions when the HCO'3/CO2 buffer system was replaced with Tris-buffer. Another carbonic anhydrase inhibitor (p-sulphonamido-benzoic acid) had similar effects on cell potentials as acetazoleamide. These results are discussed in relation to the nature of the ionic secretion produced in the tubules. 6. Occasional cells showed phasic variations in membrane potential. A possible connexion between these variations and the contractile activity of the tubules is discussed.
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PMID:Intracellular potentials in cells of the seminiferous tubules of rats. 115 7

Granulosa cells isolated from ovaries of non-cycling, cycling and pregnant rabbits of the same age were cultured in vitro either without or with pFSH (1 micrograms/ml), bLH (1 IU/ml), LH-RH (25 ng/ml) or arginine-8-vasotocin (100 ng/ml). The production of immunoreactive progesterone, estradiol-17 beta, oxytocin, arginine-8-vasopressin and cGMP was analyzed. The gonadotropins did not show any significant effects on the cells isolated from non-cycling and cycling rabbits, but not from these of pregnant ones. LH-RH inhibited and vasotocin stimulated progesterone production. All hormones used stimulated estradiol release from cells of non-cycling rabbits, while in a case of cycling animals no change was found. In the cell from pregnant females the release of estradiol was enhanced after LH treatment only. The treatment with FSH and LH (but not with LH-RH or vasotocin) resulted in a remarkable rise of granulosa vasopressin surge irrespectively to the reproductive stage. Oxytocin production by granulosa cells incubated either without or with LH, LH-RH or vasotocin was undetectable. However, FSH strongly stimulated oxytocin release. FSH and in lesser extent, LH or LH-RH (but not vasotocin) activated granulosa cGMP production in the cells from cycling and pregnant (but not from non-cycling) animals. It was also found that, in contrast to other reproductive stages, basal progesterone release from the cells of pregnant rabbits was increased, while in a case of non-cycling animals the basal estradiol release was decreased and that of cGMP was increased.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of FSH, LH, LH-RH and arginine-vasotocin on the production of steroids, nonapeptide hormones and cGMP by rabbits granulosa cells isolated at different stages of reproductive cycle. 133 99

By the 5-day culture of bovine granulosa cells both in serum-free and in serum-supplemented medium the time-dependent accumulation of PRL immunoreactivity was observed. FSH additions (10-10,000 ng/ml medium) led to a dramatic rise of immunoreactive PRL in a dose-dependent manner. LH stimulated the increase of PRL-like substance only in a great dose (10 IU/ml). Lower LH doses (0.01-1 IU/ml) had no significant influence on this process. Low doses of oxytocin (1 or 10 mIU/ml) blocked, and higher ones (100 or 1,000 mIU/ml) stimulated the granulosa PRL-like substance accumulation. Arginine-8-vasopressin (1-1,000 ng/ml), arginine-8-vasotocin (10-10,000 ng/ml), or LH-RH (10-10,000 ng/ml) failed to influence the PRL immunoreactivity accumulation in the culture medium. Present data may suggest the production of PRL-like substance by bovine ovarian cells, as well as the involvement of gonadotropins and oxytocin in the regulation of this process.
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PMID:Prolactin-like substance secretion by granulosa cells isolated from bovine ovaries. 134 Jun 86

Bovine granulosa cells express the oxytocin/neurophysin-I (OT/NP-I) gene and secrete OT in vitro. We have shown previously that bovine granulosa cells isolated from the preovulatory follicle after the LH surge secrete 20 times more OT over 5 days in culture than granulosa cells obtained before the surge. LH or FSH stimulates OT secretion in vitro by granulosa cells isolated before the LH surge. We also observed that granulosa cells of preovulatory follicles isolated before the LH surge respond to OT with an increase in progesterone secretion, suggesting that OT may be involved in regulating the follicular/luteal phase shift, or ovulation, in an autocrine fashion. The objective of this study was to determine whether the increase in OT secretion from granulosa cells after the LH surge is regulated at the level of mRNA accumulation, peptide synthesis, and/or peptide secretion. Bovine preovulatory follicles were obtained during the early follicular phase (approximately 36 h before the LH surge), during the midfollicular phase (approximately 12 h before the LH surge), or during the late follicular phase (after the LH surge). Total RNA isolated from granulosa cells and theca interna at the time of cell isolation or after culture with or without LH was subjected to Northern analysis for OT/NP-I mRNA and quantified by densitometry. OT/NP-I mRNA was not detectable or was barely detectable in granulosa cells collected during the early or midfollicular phase (n = 6 and n = 4 follicles, respectively), but a strong hybridization signal was obtained from RNA isolated after the LH surge (n = 5 follicles; P < 0.01). In contrast, OT/NP-I mRNA was not detectable in theca interna before or after the LH surge. Although OT/NP-I mRNA was not detectable in granulosa cells isolated 24 h after prostaglandin F2 alpha injection, after 24 h in culture, a weak OT/NP-I mRNA hybridization signal was observed in RNA from granulosa cells in LH-containing cultures. After 72 h in culture, granulosa cells cultured in control, as well as in LH-containing medium, exhibited a strong signal for OT/NP-I mRNA, but granulosa cells treated with LH exhibited a stronger OT/NP-I hybridization signal than control cultures (P < 0.01). Theca interna did not yield any OT/NP-I hybridization signal initially, and none was induced in culture.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Oxytocin/neurophysin-I messenger ribonucleic acid in bovine granulosa cells increases after the luteinizing hormone (LH) surge and is stimulated by LH in vitro. 144 14

Two experiments were conducted to determine whether constant infusion of oxytocin would prolong the luteal phase and inhibit uterine prostaglandin F2 alpha (PGF2 alpha) secretion in heifers. In Experiment 1, twelve heifers, treated with saline (SAL) or oxytocin (OXY) via jugular cannulae infusions (INF) or osmotic minipumps (OMP), were allotted at estrus into four treatment groups (n = 3). Treatments were: SAL-INF, SAL-OMP, OXY-INF and OXY-OMP. Physiological saline or oxytocin was given from Days 10 to 23 (Day 0 = estrus) of the estrous cycle. Method of treatment (jugular cannula infusion or osmotic minipump) had no effect (P greater than 0.05) on estrous cycle length or pattern of secretion of progesterone; therefore, data were pooled. Estrous cycle lengths were extended (P less than 0.01) for heifers which received oxytocin (25.3 +/- 0.4 d) compared to saline (20.5 +/- 0.4 d). Luteolysis did not occur in oxytocin-treated heifers until after treatment ceased. Experiment 2 was designed and conducted identically to Experiment 1 with the addition of a "challenge" injection of oxytocin (100 IU oxytocin, i.v.) given on Day 16 of the estrous cycle. Treatment of heifers with oxytocin extended (P less than 0.05) estrous cycle length by an average of 3 d compared to heifers treated with saline. The "challenge" injection induced (P less than 0.05) secretion of PGF2 alpha (as measured by the stable PGF2 alpha metabolite, 15-keto-13,14-dihydro-PGF2 alpha) in saline-treated but not oxytocin-treated heifers. In both Experiment 1 and 2, serum concentrations of FSH were elevated (P less than 0.05) in oxytocin-treated heifers. No increase was observed for LH or prolactin. The rise in estradiol-17 beta at luteolysis was not affected (P greater than 0.10) by treatment. In summary, constant infusion of oxytocin extended luteal lifespan, prolonged secretion of progesterone, and inhibited oxytocin-induced secretion of PGF2 alpha. Constant infusion of oxytocin did not affect serum concentrations of estradiol-17 beta, LH or prolactin; however, serum concentrations of FSH were elevated during the oxytocin treatment period.
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PMID:Effect of constant infusion of oxytocin on luteal lifespan and oxytocin-induced release of prostaglandin F2 alpha in heifers. 178 4

Ovarian functions are regulated by a wide variety of substances of hypothalamic, pituitary and intraovarian origin. In particular, prolactin (PRL) plays an important role in the control of ovaries. The aim of our in-vitro experiments was to prove a possibility of PRL production by bovine granulosa cells and to search into the endocrine regulators of this process. In the course of experiment 1 it was observed that the marked time-dependent accumulation of immunoreactive PRL took place during long-time cultivation of granulosa cells both in serum-free and in serum-dependent medium. After 12-24 hours of cultivation this level was reduced, but after 120 hours of cell culture the medium PRL-immunoreactivity gradually rose to exceed the starting level 2.1-2.4 times. FSH additions (10-10,000 ng/ml) led to a dramatical rise of PRL-immunoreactivity in a dose-dependent manner. A greater increase in FSH doses (1000 or 10,000 ng/ml) activated this process 14.0-18.0 times. In the other experiments the effects of LH, LH-RH and various nonapeptide hormones on the PRL-like substance production were investigated. LH stimulated PRL-like substance production at a great dose only (10 IU/ml). The lower doses did not have any significant influence on the process. Low doses of oxytocin (1 or 10 IU/ml) blocked, and higher doses (100-1000 IU/ml) stimulated the granulosa PRL-like production. Arginine-8-vasopressin (AVP) (1-1000 ng/ml), arginine-8-vasotocin (AVT) (10-1000 ng/ml), or LH-RH (10-10,000 ng/ml) failed to influence the immunoreative PRL accumulation in the culture medium.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Secretory activity of ovarian granulosa cells in cows in relation to production of prolactin or prolactin-like substances in vitro]. 180 14

To examine the relationship between corticotrophin releasing hormone (CRH), arginine vasopressin (AVP) and oxytocin (OXT) we have studied the responses of adenohypophyseal and neurohypophyseal hormones to CRH in eight patients (age 26-64 years, six female) with suspected pituitary-dependent Cushing's syndrome during bilateral, simultaneous inferior petrosal sinus catheterization. Blood samples were taken from both petrosal sinuses and a peripheral vein before, and at 5-min intervals for 15 min after, an intravenous injection of 100 micrograms human CRH1-41. CRH increased sinus AVP concentrations in all eight patients and OXT concentrations in four of five patients studied. Although AVP concentrations often increased in both sinuses, the side of maximal AVP rise was termed side(max-AVP). CRH did not affect peripheral or petrosal sinus mean concentrations of LH, FSH, GH or TSH. While there was no change in mean peripheral concentrations of AVP, OXT, ACTH, ACTH precursors or prolactin after CRH, sinus concentrations of OXT, ACTH and prolactin on side(max-AVP) were markedly elevated over contralateral values. CRH did not increase mean sinus concentrations of ACTH precursors. In seven patients with either no radiological abnormality or the pituitary fossa or a small adenoma the mean ACTH precursor/ACTH ratio in blood sampled from all sites was 2.1 +/- 0.16 (mean +/- SEM, n = 50). In a patient with a large, locally invasive tumour the mean ACTH precursor/ACTH molar ratio was 32.1 +/- 1.3 (n = 12; P less than 0.001), suggesting that alterations in this molar ratio may reflect the biological properties of the tumour. The source of CRH-stimulatable AVP and OXT remains uncertain.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Corticotrophin releasing hormone (CRH1-41) stimulates the secretion of adrenocorticotrophin, vasopressin and oxytocin but not adrenocorticotrophin precursors: evidence from petrosal sinus sampling in man. 184 86

Oxytocin has been shown to advance gonadotropin secretion in pro-estrus rats. The effects that oxytocin-induced changes have on the ovary were investigated in this study. Oxytocin administered to rats at proestrus 09.00 h, 10.00 h and 11.00 h advanced follicular growth, progesterone secretion, and the time of ovulation. However, both treated and control groups of rats ovulated similar numbers of oocytes and the oocytes released were of similar fertility. Because oxytocin has been shown to induce early LH and FSH release the effects of oxytocin administration on the ovary were possibly an indirect action involving the pituitary. The results of this investigation indicate that exogenous oxytocin alters the timing but not the fertility of periovulatory events.
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PMID:Oxytocin influences preovulatory follicular development and advances ovulation in rats. 187 18


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