PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “VASOTOCIN”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources

Arginine vasotocin gene expression in neuroendocrine, reproductive and gastrointestinal tissues of the domestic fowl: detection by reverse transcriptase polymerase chain reaction.

Arginine vasotocin gene transcripts in various tissues of the domestic fowl were detected by reverse transcriptase polymerase chain reaction followed by Southern blot analysis using a 209 bp fragment from the 3'-region of a cDNA encoding chicken arginine vasotocin as the probe. Relatively strong signals were observed with hypothalamic, adenohypophysial and proventricular RNA as the starting material. Lesser signals were obtained from RNA isolated from shell gland, adrenal gland, post-ovulatory follicles and ovarian thecal cells. Arginine vasotocin gene transcripts were undetectable in the posterior pituitary gland, small intestine and large intestine. These results suggest that in addition to its well-known antidiuretic and oxytocic actions, arginine vasotocin may act as a local neuromodulator or mediator and have other important autocrine or paracrine actions in non-hypothalamic tissues.

Animals↗

Aggression and vasotocin are associated with dominant-subordinate relationships in zebrafish.

Agonistic interactions are present throughout the animal kingdom as well as in humans. In this report, we present a model system to study neurological correlates of dominant-subordinate relationships. Zebrafish, Danio rerio, has been used as a model system for developmental biology for decades. We propose here that it is also an excellent model for studying social behavior. Adult male zebrafish were separated for 5 days and then pairs were formed and allowed to interact for 5 days. Under these conditions, aggression is prevalent and dominant-subordinate relationships are quickly established. Dominant behavior is characterized by a repeated pattern of chasing and biting, whereas subordinates engage in retreats. By day 5, the dominant-subordinate relationship was firmly established and there were differences in behavior over time. Chases, bites and retreats were all less frequent on day 5 of the social interaction than on day 1. Arginine vasotocin is the teleostean homologue of arginine vasopressin, a neuropeptide whose expression has been linked to aggression and social position in mammals. Immunohistochemistry indicated differences in vasotocin staining between dominant and subordinate individuals. Dominant individuals express vasotocin in one to three pairs of large cells in the magnocellular preoptic area whereas subordinate individuals express vasotocin in 7-11 pairs of small cells in the parvocellular preoptic area. These results suggest that the vasotocinergic system may play a role in shaping dominant-subordinate relationships and agonistic behavior in this model organism.

Aggression↗

Effects of testosterone on sexually dimorphic parvocellular neurons expressing vasotocin mRNA in the male quail brain.

In situ hybridization with a P33-labelled cDNA probe was used to analyze the effects of castration and replacement therapy by testosterone on the number of neurons expressing vasotocin mRNA in the male quail brain. Castration completely eliminated neurons expressing vasotocin mRNA in the previously described parvocellular vasotocin cell groups, located in the medial preoptic nucleus and in the anterior and posterior part of the medial subdivision of the bed nucleus of the stria terminalis. These effects were completely reversed by a 3-week treatment with exogenous testosterone. No marked change in vasotocin expression could be detected in the magnocellular cell groups located in the paraventricular and supraoptic nuclei. These data indicate that the testosterone-induced changes in the vasotocinergic innervation of the quail medial preoptic region and bed nucleus of the stria terminalis result from controlling mechanisms at the pretranslational, presumably transcriptional level. These control mechanisms are therefore very similar to those described for the rat brain despite the existence of major differences in the neuroanatomical organization of this peptidergic system in the two species.

Animals↗

Effect of testosterone on the distribution of vasotocin immunoreactivity in the brain of the zebra finch, Taeniopygia guttata castanotis.

The distribution of vasopressin or vasotocin immunoreactive cells and fibers in the lateral septum and the bed nucleus of the stria terminalis are sexually dimorphic in many vertebrates including several species of birds examined to date. We examined the vasotocin-like immunoreactivity in the zebra finch brain. Male birds had a higher level of immunoreactive staining in some telencephalic and diencephalic regions. The density of immunostaining increased in the testosterone-treated females to levels typically seen in males. The sexual dimorphism and testosterone dependence of the vasotocin-like immunoreactivity are similar to that found in the canary. Thus this pattern of vasotocin localization and testosterone dependence may be a general feature in brains of passerine songbirds.

Animals↗

Photoaffinity, biotinyl, and iodo analogues as probes for vasotocin receptors.

Vasotocin (AVT) analogues with tyrosine or phenylalanine in position 9, i.e., [9-tyrosine]AVT, [2-phenylalanine,-9-tyrosine]AVT, and 1-desamino[9-(p-aminophenylalanine)]AVT, were synthesized by the solid-phase method. These compounds showed a high biological activity in the hydroosmotic toad bladder assay. Using the chemically reactive functional groups on tyrosine and p-aminophenylalanine in position 9, we prepared iodinated, photoreactive, and affinity ligands, i.e., [2-phenylalanine,9-(iodotyrosine)]AVT, 1-desamino[9-(p-azidophenylalanine)]AVT, and 1-desamino[9-(biotinylphenylalanine)]AVT, respectively. Half-maximal hydroosmotic responses (ED-50 values) were obtained with 2.5 X 10(-9) M for the iodinated analogue, with 0.9 X 10(-10) M for the photoaffinity analogue, and with 1.2 X 10(-8) M for the biotinyl analogue. The hydroosmotic activity of the biotinyl analogue was reversed following addition of avidin, whereas the photoaffinity analogue induced a persistent response following UV irradiation that was not reversed upon repeated and prolonged periods of washout. These analogues of vasotocin are the most potent that have been synthesized to date, and they should serve as useful probes in the isolation and characterization of vasotocin receptors in toad bladders and tissues from other species that use vasotocin as an antidiuretic/pressor principle. The photoaffinity and biotinyl analogues had a rat antidiuretic activity of 66 and 40 units/mg, respectively. These compounds are, therefore, also suitable for the isolation of V-2 vasopressin receptors from mammalian tissues.

Affinity Labels↗

The effect of oxytocin and vasotocin upon progesterone, testosterone and estradiol 17 beta-secretion by the luteal cells from cyclic pigs.

Porcine luteal cells were obtained from the corpora lutea on the 13th day of the estrous cycle. The cells were digested with 0.25% trypsin and suspended in the Medium 199 with an addition of 10% calf serum, at a concentration of 5 X 10(4) cells/ml. The cells were incubated with or without 4 and 40 mi.u./ml of oxytocin, 10 and 100 ng/ml of arginine-vasotocin, 1 microgram LH and 50 U/ml hCG. Levels of progesterone, testosterone and estradiol 17 beta were determined with the radioimmunological method, following 6 h incubation. It was found that progesterone secretion under the influence of oxytocine (4 mi.u./ml) was less than in the control group and in the group with LH. Similarly, arginine-vasotocin at a dose of 10 ng/ml inhibited progesterone secretion (P less than 0.05). Higher doses of these peptides had no suppressive effect on the luteal cells. Oxytocin and arginine-vasotocin had no influence on testosterone secretion by luteal cells. However, these cells produced less (P less than 0.05) estradiol 17 beta under the influence of oxytocine than of hCG. The results point to a direct effect of oxytocin and arginine-vasotocin on steroidogenesis in the corpora lutea of cyclic pigs.

Animals↗

Conformational studies on arginine vasopressin and arginine vasotocin by proton magnetic resonance spectroscopy.

The assignments and partial conformational analysis of the 220-MHz (1)H nuclear magnetic resonance spectrum of the neurohypophyseal hormones arginine vasopressin and arginine vasotocin in uniformaly deuterated dimethylsulfoxide are reported. The chemical shifts, vicinal coupling constants, temperature coefficients of chemical shifts, and proton-deuterium exchange rates for protons of arginine vasopressin and arginine vasotocin are compared with those for the corresponding protons of the related neurohypophyseal hormones lysine vasopressin and oxytocin. Although to a first approximation the backbone conformations of the hormones exhibit conformational similarities, spectral differences are seen for protons in the amino acid residues that comprise the 20-membered ring moieties. It is inferred that there is a gradual shift in the average conformation in going from arginine vasopressin and lysine vasopressin via arginine vasotocin to oxytocin. As judged on the basis of earlier studies, it is evident that the C-terminal acyclic tail moiety exhibits an enhanced mobility over that of the ring moiety in all of the neurohypophyseal hormones studied and, moreover, that this motion is greater in arginine vasopressin and arginine vasotocin than in oxytocin.

Arginine↗

Influence of vasotocin and isoproterenol on the in vitro motility of the follicular stalks and infundibulum in the domestic hen.

Since in the hen ovulation and oviposition are in close temporal relationship we studied the effect of vasotocin, the principal neurohypophysial oxytocic substance in birds, on in vitro motility of follicular stalks of the most recently ruptured and largest preovulatory follicle and of longitudinal and circular infundibular strips, both in the absence and the presence of a beta-adrenergic drug (isoproterenol, 1 x 10(-7) mol/l). Infundibular strips were rather insensitive to vasotocin (3 x 10(-9) - 3 x 10(-6) mol/l) either in the absence or presence of isoproterenol. However, tissue strips from the follicular stalks were significantly stimulated by vasotocin (3 x 10(-9) - 3 x 10(-7) mol/l). Isoproterenol attenuated these effects. From these in vitro studies it was concluded that vasotocin may have a facilitating function in the process of ovulation.

Animals↗

Diurnal rhythm of vasotocin in the pineal of the male rat.

The pineal content of arginine vasotocin in the male rat is subject to diurnal changes, having a high value around noon and a low value around midnight. Since in rats exposed to 24 h constant light the pineal content in arginine vasotocin decreases, and in the rats exposed to 24 h constant darkness the pineal content in arginine vasotocin increases, it appears that during the night both the synthesis and release of arginine vasotocin is enhanced.

Animals↗

Vasotocin-like activity in the plasms of the euryhaline frog (Rana cancrivora) after transfer from fresh water to saline.

When Rana cancrivora were collected from fresh water and dehydrated (weight loss 4-10%) by exposure to saline, the plasma titre of hydro-osmotic activity, measured by amphibian bladder assay, was increased three-to fourfold. This activity, which was abolished by thioglycollate and by incubation with tyrosinase or trypsin, was ascribed to vasotocin. The plasma vasotocin activities (hydrated and dehydrated frogs respectively) were estimated to be 0-03-0-5 and 0-15-0-25 mug/1; if referred to oxytocin as a standard the equivalent values were 10 and 30-60 mu./ml. Assuming that the increase represented released pituitary hormone, the amount of vasotocin released by osmotic dehydration was calculated to be of the order of 1 ng. Pituitary glands of hydrated and dehydrated frogs were estimated to have 0.15 and 0-18 mug vasotocin/gland respectively. The possible physiological function of released vasotocin in promoting reabsorption of urea from the urinary bladder is discussed in relation to the euryhaline ability of R. cancrivora.

Animals↗

Suppression of the luteinizing hormone releasing effect of luteinizing hormone releasing hormone by arginine-vasotocin in immature male dogs.

Arginine-vasotocin (0.1 or 10 ng/kg body wt) was administered into the carotid artery of anaesthetized immature male dogs 3 h before the administration of a standard dose of luteinizing hormone releasing hormone (LH-RH, 5 microgram/kg body wt) into the same vessel. The rate of secretion of 17-oxosteroids by the testes in vivo served as an index of luteinizing hormone (LH) secretion. The administration of LH-RH into the carotid artery of control dogs which had been injected with isotonic saline caused a slight but definite increase in the secretion of testicular 17-oxosteroids. This effect of LH-RH on the testicular secretion of steroids was markedly reduced by pretreatment with arginine-vasotocin. However, the testicular response to the i.v. administration of human chorionic gonadotrophin (5 i.u./kg body wt) was unaffected by pretreatment with arginine-vasotocin (10 ng/kg body wt). These results indicate that in immature male dogs, arginine-vasotocin is able to inhibit the action of LH-RH by acting directly on the anterior pituitary gland.

17-Ketosteroids↗

Effects of arginine vasotocin on levels of plasma gonadotropins and prolactin in ovariectomized conscious rats.

Arginine vasotocin was injected into the third ventricle or intravenously in conscious, ovariectomized rats and its effect on gonadotropin and prolactin release evaluated. The peptide lowered plasma levels of both LH and prolactin in doses of 40 or 100 ng given intraventricularly. The higher dose was slightly more effective than the lower dose. Intravenous injection of a 1-microgram dose of vasotocin failed to alter plasma LH in the ovariectomized animals; however, a 5-micrograms dose induced a slight depression apparent at only 60 min following injection. Intravenous injection of 1 microgram produced a significant lowering of plasma prolactin, whereas a dramatic lowering followed the injection of the higher dose. Plasma FSH was unaffected in these experiments. Incubation of dispersed anterior pituitary cells from ovariectomized rats with various doses of vasotocin revealed no effect of the peptide on the release of FSH, LH, or prolactin. It also did not alter the response to LHRH, but it partially blocked the action of dopamine to inhibit prolactin release. The data indicate that quite low doses of arginine vasotocin act within the brain to inhibit LH and prolactin secretion in ovariectomized, conscious animals.

Animals↗

Structure and organization of the isotocin and vasotocin genes from teleosts.

Oxytocin and vasopressin are structurally related mammalian neurohypophysial hormones with distinct physiological activities. Homologues of these two hormones are found in all vertebrate groups except the primitive cyclostomes in which only a vasopressin-like hormone has been reported so far. Genes encoding the mammalian oxytocin and vasopressin hormone precursors exhibit a similar genomic organisation, and are closely linked (3.5 kb to 12 kb apart) in a tail-to-tail manner suggesting a common evolutionary origin. However, no linkage among genes of the vasopressin/oxytocin family has been demonstrated in any of the lower vertebrates. The Japanese pufferfish, Fugu rubripes, has been shown to have a very compact genome of about 400 Mb with very few repetitive sequences. We used this model vertebrate genome to analyse the genomic organisation of vasotocin and isotocin genes, the teleost homologues of vasopressin and oxytocin. We have cloned and mapped the vasotocin/isotocin locus in Fugu and obtained complete nucleotide sequences of the vasotocin and isotocin genes. The coding sequences of the Fugu vasotocin and isotocin genes are interrupted by two introns at identical positions, similar to their homologues in higher vertebrates. The deduced amino acid sequences as well as the coding sequences of the two genes show high homology in the neurophysin region. Furthermore, the two genes are linked in a tandem manner with an intergenic region of about 20 kb. Random sequencing has shown that there are at least two known vertebrate genes in the intergenic region. Genomic organisation of the Fugu vasotocin/isotocin locus suggests that the teleost vasotocin and isotocin genes have evolved from a common ancestor through tandem duplication and that this locus seems to have undergone a localised reorganisation during vertebrate evolution.

Amino Acid Sequence↗

Immunocytochemical studies of vasotocin, mesotocin, and neurophysins in the Xenopus hypothalamo-neurohypophysial system.

Mesotocinergic and vasotocinergic neurons, which constitute the principal neurons in the hypothalamo-neurohypophysial system in Xenopus, were studied by immunocytochemical techniques. Antibodies that could unequivocally distinguish mesotocin, vasotocin, and their respective neurophysins were used in these studies. A monoclonal antibody directed at rat oxytocin-associated neurophysin (PS-36) detected an antigen that was colocalized with vasotocin, whereas a monoclonal antibody to rat vasopressin-associated neurophysin (PS-45) crossreacted with an antigen in mesotocinergic cells. As vasotocin is regarded as an evolutionary precursor of vasopressin, and as mesotocin is usually associated with oxytocin, we were surprised to see this apparent eptitope switch in the associated neurophysins. One interpretation of this epitope switch is that the final exons encoding for the carboxy-terminals of the mammalian neurophysins, which contain the PS-45 and PS-36 antibody epitopes, are in reversed positions in Xenopus. Approximately 4,000 mesotocinergic and vasotocinergic neurons and their fibers were topographically mapped in the Xenopus hypothalamus. The two types of neurons were intermingled and scattered throughout a large contiguous region including but not limited to the preoptic recess. Small, medium size, and large cells contained these antigens. Immunoreactive fibers were seen in the preoptic area, the neurohypophysial tract, the median eminence, and the neural lobe of the pituitary. The neurophysin-specific monoclonal antibodies have several advantages as phenotypic markers in development; i.e., high titer, low background, and affinity for the prohormone forms as well as for the fully processed neurophysin polypeptides. Their antigens are related gene products whose expression is central to the identity of the two cell types and whose expression is differentially controlled in development. This characterization of their adult distribution provides a basis for future studies of the development of peptidergic phenotype in the central nervous system of Xenopus.

Animals↗

Vasotocin-sensitive adenylate cyclase in frog glomeruli.

Adenylate cyclase sensitivity to neurohypophyseal hormones was investigated in isolated glomeruli and in nephron segments microdissected from collagenase-treated kidneys of Rana ridibunda. Vasotocin treatment increased adenylate cyclase activity in glomeruli and in collecting ducts and did not modify it in proximal convoluted tubules and in early and late distal tubules. In glomeruli, the hormonal stimulation resulted mainly in a decrease in the Km value for adenylate cyclase, which means a higher affinity for substrate (ATP) to the enzyme, whereas the response to forskolin was accounted for by increases both in affinity for substrate and in maximal adenylate cyclase velocity. The homologous neurohypophyseal hormones stimulated frog glomerular adenylate cyclase with the following rank order of affinities: hydrin 1 > or = AVT = AVP > or = hydrin 2 > OT > or = mesotocin > isotocin; structural analogs dDAVP, VDAVP, dVDAVP, and [Phe2,Orn8]VT had weak agonistic properties, [Thr4,Gly7]OT was inactive, and the antagonists OVTA, d(CH2)5Tyr(Et)2VAVP, and des-Gly9-d(CH2)5Tyr(Et)2VAVP inhibited hormone-induced enzyme activation with similar apparent inhibition constants. The vasotocin receptors triggering adenylate cyclase stimulation in frog glomeruli differ pharmacologically from V2 vasopressin receptors of mammalian kidneys and may also differ from V2-like vasotocin receptors of amphibian skin and urinary bladder.

Adenosine Triphosphate↗

Cloning of pro-vasotocin and pro-isotocin cDNAs from the flounder Platichthys flesus; levels of hypothalamic mRNA following acute osmotic challenge.

Sequences coding for pro-vasotocin and pro-isotocin have been identified by screening a flounder (Platichthys flesus) hypothalamic cDNA library. The 1074-bp proVT and 727-bp proIT sequences contain a signal peptide and hormone, connected to a neurophysin by a Gly-Lys-Arg sequence. Both sequences also have an elongated carboxyl-terminal with a leucine-rich core resembling copeptin but lacking the amino terminal Arg residue. The levels of pro-vasotocin and pro-isotocin mRNA in the hypothalamus were measured concomitantly with pituitary AVT content and plasma AVT concentration following acute transfer of fish between freshwater and seawater. Three days after transfer from seawater to freshwater there appears to be a down regulation of the AVT hormone system with a fall in hypothalamic pro-vasotocin mRNA levels, an increase in pituitary AVT content, and a fall in plasma levels, but these changes did not achieve statistical significance compared to controls. No change in the AVT system was detected 3 days following the transfer of fish from freshwater to seawater. Hypothalamic isotocin mRNA levels did not change following hypo- or hyperosmotic challenge.

Amino Acid Sequence↗

Ultrastructural characterization of neurosecretory fibres immunoreactive for vasotocin, isotocin, somatostatin, LHRH and CRF in the pituitary of a teleost fish, Poecilia latipinna.

Using the electron-microscopic immunogold method, vasotocin, isotocin, somatostatin (SRIF), gonadotrophin-releasing hormone (LHRH) and corticotrophin-releasing factor (CRF)-like immunoreactivities were localized in separate neurosecretory fibres in the pituitary of a teleost fish Poecilia latipinna. Antigenicities were preserved in sections of conventionally fixed tissue, except in the case of LHRH and CRF-like substances which were sensitive to osmium postfixation. Under the same fixation conditions, ultrastructural differences were observed between the 5 fibre types, and morphometric analysis of their granule sizes revealed significant differences in mean diameter except between vasotocin and isotocin fibres. Terminal-like regions of each type were identified on blood vessels, glial cells or other fibres in the neurohypophysis, on the basement lamina of the adenohypophysis, or directly on adenohypophysial endocrine cells. The fibres containing the two neurohypophysial hormones, originating from separate preoptic perikarya, were intermingled with, and may form endings near all the adenohypophysial cell types except those secreting prolactin. Although both types had similar mean granule diameters, the granules in the vasotocin fibres (mean 135 nm) were markedly less electron dense than those in the isotocin fibres (mean 140 nm). SRIF-immunoreactive fibres (mean 101 nm) appeared to form synapse-like endings on the somatotrophs, and a few thyrotrophs in the proximal pars distalis, and near the pars intermedia cells. An LHRH-positive type (mean 103 nm) contacted only the gonadotrophs of the proximal pars distalis. The rarer CRF-like fibres (mean 116 nm) appeared to project mainly towards the pars intermedia, but a few appeared to terminate rostrally near the adrenocorticotrophic cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Immunocytochemical localization of peptidergic cells in the neuro-endocrine system of the Colorado potato beetle, Leptinotarsa decemlineata, with antisera against vasopressin, vasotocin and oxytocin.

Antisera against vasopressin, vasotocin, oxytocin, neurophysin-1 and neurophysin-2 were used to investigate immunocytochemically the presence of neurons containing substances antigenically related to these peptides in the nervous system of the Colorado potato beetle. Ten different antisera were used, four against vasopressin, three against oxytocin and one against vasotocin, neurophysin-1, and neurophysin-2. Immunoreactivity was shown by all antisera except those against the neurophysins. The vasopressin antisera all gave different results. One antiserum revealed only a single neuron pair, whereas others revealed in addition one or two other different cell groups. The oxytocin antisera likewise revealed different neurons. The fixation procedure influenced the outcome of the immunocytochemical reaction. Immunoreactivity as revealed by vasopressin, vasotocin and oxytocin antisera is often co-localized in the same neurons; solid phase adsorptions showed that this is due to cross-reactivity of the antisera. Some of the immunoreactive neurons are identical to those recently described to contain a bovine pancreatic polypeptide/FMRFamide-like peptide. This co-localization is probably not due to a cross-reaction. These findings indicate the presence of several vasopressin-like and oxytocin-like substances which in the Colorado potato beetle all have a different degree of immunocytochemical resemblance to vasopressin and oxytocin.

Animals↗