The Experts below are selected from a list of 198 Experts worldwide ranked by ideXlab platform

Ross A D Bathgate - One of the best experts on this subject based on the ideXlab platform.

  • differential expression of Mesotocin receptors in the uterus and ovary of the pregnant tammar wallaby
    Reproduction, 2005
    Co-Authors: Andrew L Siebel, Ross A D Bathgate, Laura J Parry
    Abstract:

    Mesotocin, an oxytocin-like peptide, is released in highest concentrations during parturition in macropodid marsupials. In late pregnant wallabies, uterine sensitivity to Mesotocin increases markedly in the myometrium of the gravid uterus. This coincides with a significant increase in myometrial Mesotocin receptor concentrations 3-4 days before term. To date, there is no information on Mesotocin receptor gene expression in female wallaby reproductive tissues. This study aimed to examine Mesotocin receptor gene expression in the uterus and ovaries of pregnant tammar wallabies, and to localise Mesotocin receptors within the uterus. An RT-PCR strategy produced a consensus nucleotide sequence of 834 bp, which encoded 278 amino acids of transmembrane domains I to VI. This protein sequence has approximately 80% homology with the bovine and rat oxytocin receptor exon 2 region. Only one Mesotocin receptor was detected in the tammar genome. The myometrium and mammary gland both expressed a 4.1 kb Mesotocin receptor gene transcript. Myometrial Mesotocin receptor gene expression increased on day 22 of the 26-day gestation and was significantly higher in the gravid than the non-gravid uterus in late pregnancy. This pattern of Mesotocin receptor gene expression paralleled Mesotocin receptor concentrations. Mesotocin binding sites were localised only to the myometrium, the highest densities being observed in the gravid uterus. Finally, this study showed high expression of Mesotocin receptors in the corpus luteum. The pattern of luteal Mesotocin receptor expression differed from the myometrium, with a decrease in Mesotocin receptors occurring on the day of expected births.

  • up regulation of Mesotocin receptors in the tammar wallaby myometrium is pregnancy specific and independent of estrogen
    Biology of Reproduction, 2002
    Co-Authors: Andrew L Siebel, Ross A D Bathgate, Helen M Gehring, Chris D Nave, Clare E Borchers, Laura J Parry
    Abstract:

    The oxytocin-like peptide of most Australian marsupials is Mesotocin, which stimulates uterine contractions and is important for normal birth in the tammar wallaby. Female marsupials have two uteri and, in monovular species such as the tammar, one uterus is gravid with a single fetus, whereas the contralateral uterus is nongravid. A significant increase in myometrial Mesotocin receptor concentrations occurs only in the gravid uterus on Day 23 of the 26-day gestation. This study examined whether or not Mesotocin receptors are present in the myometrium and are up-regulated at the equivalent stage of the luteal phase in unmated tammars. In contrast to the marked increase in Mesotocin receptor mRNA and protein concentrations in the myometrium of the gravid uterus during pregnancy, receptors did not increase in the unmated animals. There were also no significant differences between the two uteri, except on Day 27. Plasma profiles of peripheral estradiol-17β and progesterone did not differ significantly between pregnant and nonpregnant cycles. However, progesterone concentrations were significantly lower on Day 1 postpartum compared with Day 27 of the nonpregnant cycle. In pregnant tammars, the molar ratio of circulating estradiol-17β to progesterone increased significantly between Day 25 of gestation and 1 day postpartum, but was not correlated with an increase in Mesotocin receptor concentrations in either uterus. The data confirm that a local fetal influence is more important than systemic factors, such as estrogen, in the regulation of uterine Mesotocin receptors in the tammar wallaby.

  • mammalian Mesotocin cdna sequence and expression of an oxytocin like gene in a macropodid marsupial the tammar wallaby
    General and Comparative Endocrinology, 2000
    Co-Authors: Laura J Parry, Ross A D Bathgate, Richard Ivell
    Abstract:

    Abstract The oxytocin (OT)-like peptide of most Australian marsupials is Mesotocin (MT), which differs from OT by substitution of isoleucine for leucine at position 8. To date, the only information on the evolution of the OT peptide in marsupials is based on the sequence of the 9-amino acid peptide itself. The main objective of this study was to obtain the nucleotide and derived amino acid sequences of a marsupial MT precursor for comparison with known OT and MT precursors of eutherians and nonmammalian vertebrates. The structural organization and sequence of the MT gene and its specific transcript were established in a macropodid marsupial, the tammar wallaby, using PCR strategies with a combination of genomic DNA and reverse-transcribed hypothalamic RNA. A consensus genomic sequence of 1221 bp was produced which, by comparison with the expressed cDNA sequence, included two intron sequences of 480 and 188 bp. The tammar MT precursor molecule consists of a 32-amino acid signal peptide, followed by the MT-encoding region and the Gly-Lys-Arg carboxy-terminal cleavage and amidation signal which separates the nonapeptide from the 92-amino acid neurophysin. At the amino acid level, the MT precursor is more similar to eutherian OT precursors than to nonmammalian MT, isotocin, or vasotocin precursors. Northern analysis demonstrated a single transcript of approximately 0.6 kB in the hypothalamus. Mesotocin mRNA is also present in several tissues of the reproductive tract, including the corpus luteum, follicle, uterus, and placenta. Within the ovary, MT transcripts are localized predominantly in the granulosa cells of antral follicles with some positive hybridization signals in cells of the theca interna. This pattern of MT gene expression in marsupials is very similar to that of OT in eutherians and suggests a conserved physiology in the mammalian ovary.

  • Mesotocin and oxytocin in the brain and plasma of an australian marsupial the northern brown bandicoot isoodon macrourus
    Comparative Biochemistry and Physiology Part A: Physiology, 1992
    Co-Authors: Ross A D Bathgate, Conrad Sernia, R T Gemmell
    Abstract:

    Abstract 1. 1. Mesotocin (MT) and oxytocin (OT) were measured in the brain and plasma of bandicoots using reverse phase high performance liquid chromatography and specific radioimmunoassays. 2. 2. MT and OT were found in the pituitary (1.25 ± 0.10 μg/MT; 0.725 ± 0.077 μg/OT) and hypothalamus (38.37 ± 6.46 ng/MT; 19.1 ± 4.61 ng/OT). Smaller amounts were present in the cerebral cortex. 3. 3. Basal plasma concentrations ranged from 1.5 to 8.1 pg/ml for both peptides (N = 14) and were elevated by stress. 4. 4. It was concluded that both MT and OT are secreted by the bandicoot brain and that stress stimulates secretion.

  • Mesotocin in the brain and plasma of an australian marsupial the brushtail possum trichosurus vulpecula
    Neuropeptides, 1990
    Co-Authors: Ross A D Bathgate, Conrad Sernia, R T Gemmell
    Abstract:

    Oxytocic peptides extracted from the brain and plasma of the brushtail possum, Trichosurus vulpecula, were separated by reverse-phase high pressure lipid chromatography (HPLC) and quantified by specific radioimmunoassays for oxytocin (OT) and Mesotocin (MT). The pituitary, hypothalamus and cerebral cortex were found to contain MT only in quantities of 3.9 ± 0.2 (SE) ug, 17.6 ± 0.6 ng and 21.0 ± 2.6 ng respectively. The plasma concentration of MT varied according to the degree of stress of the possum. In anaesthetized animals values of 39.7 ± 9.7 pg/ml (11 males) and 31.5 ± 12.9 pg/ml (6 females) were obtained; in four conscious catheterized animals, 9.4 ± 6.3 pg/ml. Samples taken from three anaesthetized animals during exsanguination contained 271 ± 102 (SD) pg MT/ml. It was concluded that hypothalamic and extra-hypothalamic MT is present in the marsupial brain and that as in placental mammals, stress stimulates the secretion of Mesotocin.

Laura J Parry - One of the best experts on this subject based on the ideXlab platform.

  • differential expression of Mesotocin receptors in the uterus and ovary of the pregnant tammar wallaby
    Reproduction, 2005
    Co-Authors: Andrew L Siebel, Ross A D Bathgate, Laura J Parry
    Abstract:

    Mesotocin, an oxytocin-like peptide, is released in highest concentrations during parturition in macropodid marsupials. In late pregnant wallabies, uterine sensitivity to Mesotocin increases markedly in the myometrium of the gravid uterus. This coincides with a significant increase in myometrial Mesotocin receptor concentrations 3-4 days before term. To date, there is no information on Mesotocin receptor gene expression in female wallaby reproductive tissues. This study aimed to examine Mesotocin receptor gene expression in the uterus and ovaries of pregnant tammar wallabies, and to localise Mesotocin receptors within the uterus. An RT-PCR strategy produced a consensus nucleotide sequence of 834 bp, which encoded 278 amino acids of transmembrane domains I to VI. This protein sequence has approximately 80% homology with the bovine and rat oxytocin receptor exon 2 region. Only one Mesotocin receptor was detected in the tammar genome. The myometrium and mammary gland both expressed a 4.1 kb Mesotocin receptor gene transcript. Myometrial Mesotocin receptor gene expression increased on day 22 of the 26-day gestation and was significantly higher in the gravid than the non-gravid uterus in late pregnancy. This pattern of Mesotocin receptor gene expression paralleled Mesotocin receptor concentrations. Mesotocin binding sites were localised only to the myometrium, the highest densities being observed in the gravid uterus. Finally, this study showed high expression of Mesotocin receptors in the corpus luteum. The pattern of luteal Mesotocin receptor expression differed from the myometrium, with a decrease in Mesotocin receptors occurring on the day of expected births.

  • seasonal changes in Mesotocin and localization of its receptor in the prostate of the brushtail possum trichosurus vulpecula
    Biology of Reproduction, 2005
    Co-Authors: Jo W Fink, Laura J Parry, B J Mcleod, Stephen J Assinder, H D Nicholson
    Abstract:

    The prostate gland in the brushtail possum grows and regresses seasonally. It has similarities to the human prostate and may therefore provide a unique model for investigating prostatic hyperplasia. Oxytocin has been implicated in the regulation of prostate growth in eutherian mammals, and the initial aim of this study was to identify and localize the marsupial equivalent, Mesotocin, and its receptor in the prostate of the brushtail possum. Seasonal changes in prostatic Mesotocin concentrations and receptor localization were then assessed and related to prostate growth. Mesotocin and Mesotocin receptor gene transcripts with high sequence homology to eutherian oxytocin/oxytocin receptors were demonstrated, and Mesotocin, neurophysin, and the receptor were all localized predominantly in the epithelial cells of the glandular acini. Western blot analysis confirmed the presence of a single immunoreactive receptor protein of ;60 Mr 23 . Prostatic Mesotocin concentrations were highest immediately before the increases in prostate weight associated with the autumn and spring breeding periods. At this time, Mesotocin receptors were also present in the prostatic capsule in addition to those present in the glandular tissue. Mesotocin concentrations proceeded to decrease in association with the regression of prostate size toward the end of the breeding periods. No significant differences were present in serum testosterone or dihydrotestosterone throughout the year. The identification of Mesotocin and its receptor in the possum prostate and the demonstration of seasonal changes in local Mesotocin concentrations preceding changes in prostate size suggests that Mesotocin may play a physiological role in regulating prostate growth and regression. male reproductive tract, oxytocin, prostate, seasonal reproduction, testosterone

  • up regulation of Mesotocin receptors in the tammar wallaby myometrium is pregnancy specific and independent of estrogen
    Biology of Reproduction, 2002
    Co-Authors: Andrew L Siebel, Ross A D Bathgate, Helen M Gehring, Chris D Nave, Clare E Borchers, Laura J Parry
    Abstract:

    The oxytocin-like peptide of most Australian marsupials is Mesotocin, which stimulates uterine contractions and is important for normal birth in the tammar wallaby. Female marsupials have two uteri and, in monovular species such as the tammar, one uterus is gravid with a single fetus, whereas the contralateral uterus is nongravid. A significant increase in myometrial Mesotocin receptor concentrations occurs only in the gravid uterus on Day 23 of the 26-day gestation. This study examined whether or not Mesotocin receptors are present in the myometrium and are up-regulated at the equivalent stage of the luteal phase in unmated tammars. In contrast to the marked increase in Mesotocin receptor mRNA and protein concentrations in the myometrium of the gravid uterus during pregnancy, receptors did not increase in the unmated animals. There were also no significant differences between the two uteri, except on Day 27. Plasma profiles of peripheral estradiol-17β and progesterone did not differ significantly between pregnant and nonpregnant cycles. However, progesterone concentrations were significantly lower on Day 1 postpartum compared with Day 27 of the nonpregnant cycle. In pregnant tammars, the molar ratio of circulating estradiol-17β to progesterone increased significantly between Day 25 of gestation and 1 day postpartum, but was not correlated with an increase in Mesotocin receptor concentrations in either uterus. The data confirm that a local fetal influence is more important than systemic factors, such as estrogen, in the regulation of uterine Mesotocin receptors in the tammar wallaby.

  • mammalian Mesotocin cdna sequence and expression of an oxytocin like gene in a macropodid marsupial the tammar wallaby
    General and Comparative Endocrinology, 2000
    Co-Authors: Laura J Parry, Ross A D Bathgate, Richard Ivell
    Abstract:

    Abstract The oxytocin (OT)-like peptide of most Australian marsupials is Mesotocin (MT), which differs from OT by substitution of isoleucine for leucine at position 8. To date, the only information on the evolution of the OT peptide in marsupials is based on the sequence of the 9-amino acid peptide itself. The main objective of this study was to obtain the nucleotide and derived amino acid sequences of a marsupial MT precursor for comparison with known OT and MT precursors of eutherians and nonmammalian vertebrates. The structural organization and sequence of the MT gene and its specific transcript were established in a macropodid marsupial, the tammar wallaby, using PCR strategies with a combination of genomic DNA and reverse-transcribed hypothalamic RNA. A consensus genomic sequence of 1221 bp was produced which, by comparison with the expressed cDNA sequence, included two intron sequences of 480 and 188 bp. The tammar MT precursor molecule consists of a 32-amino acid signal peptide, followed by the MT-encoding region and the Gly-Lys-Arg carboxy-terminal cleavage and amidation signal which separates the nonapeptide from the 92-amino acid neurophysin. At the amino acid level, the MT precursor is more similar to eutherian OT precursors than to nonmammalian MT, isotocin, or vasotocin precursors. Northern analysis demonstrated a single transcript of approximately 0.6 kB in the hypothalamus. Mesotocin mRNA is also present in several tissues of the reproductive tract, including the corpus luteum, follicle, uterus, and placenta. Within the ovary, MT transcripts are localized predominantly in the granulosa cells of antral follicles with some positive hybridization signals in cells of the theca interna. This pattern of MT gene expression in marsupials is very similar to that of OT in eutherians and suggests a conserved physiology in the mammalian ovary.

  • Release of an oxytocic peptide at parturition in the marsupial, Macropus eugenii
    Reproduction, 1996
    Co-Authors: Laura J Parry, F. J. Guymer, T. P. Fletcher, Marilyn B Renfree
    Abstract:

    The oxytocic peptide Mesotocin was measured in plasma samples collected throughout pregnancy in the conscious tammar wallaby, Macropus eugenii. Plasma Mesotocin and the prostaglandin metabolite 13,14-dihydro-15-oxo-prostaglandin F2\g=a\ were also assessed immediately prepartum and during parturition. A radioimmunoassay for Mesotocin was validated in the tammar and this assay allowed direct measurement in 50 \g=m\lunextracted plasma with a sensitivity of 12.5 pmol l\m=-\1. Plasma concentrations of Mesotocin remained basal (approximately 15 pmol l\m=-\1) at all stages of pregnancy, including prepartum. A significant (P < 0.05) increase in plasma Mesotocin was observed only immediately after delivery of the neonate and this increase was maintained for at least 15 min postpartum. Mesotocin concentrations returned to basal values 2 h after birth. Peak concentrations of Mesotocin of 516.7 \m=+-\108.1 pmol l\m=-\1were measured within 2 min of birth. This peak coincided with a short-lived peak in concentration of prostaglandin F2\g=a\metabolite immediately after birth (2.1 \m=+-\0.4 nmol l\m=-\1) which decreased to less than 0.3 nmol l\m=-\1within 2 h postpartum. These data demonstrate that Mesotocin is released during, or immediately after, delivery and appears to parallel the profile of circulating prostaglandin F2\g=a\metabolite in this marsupial.

Yupaporn Chaiseha - One of the best experts on this subject based on the ideXlab platform.

  • distribution of Mesotocin immunoreactive neurons in the brain of the male native thai chicken
    Acta Histochemica, 2017
    Co-Authors: Boonyarit Kamkrathok, Mohamed El E Halawani, Tom E Porter, Yupaporn Chaiseha
    Abstract:

    Abstract Mesotocin (MT), a homolog of oxytocin (OT) in mammals, is a nonapeptide neurohypophysial hormone that is mainly synthesized in specific neuronal groups within the hypothalamus and released from the posterior pituitary gland in amphibian, reptilian, and avian species. MT is associated with the neuroendocrine regulation of reproductive cycle and maternal behaviors in female native Thai chickens. Male birds exhibit parental behaviors as well. However, there are limited data regarding the role(s) of the MTergic system in males. Thus, the objective of this study was to elucidate the localization of the MT neuronal groups in the brain of male native Thai chickens. The distributions of MT-immunoreactive (-ir) neurons and fibers in the brain were studied utilizing immunohistochemistry technique. The results revealed that MT-ir neurons and fibers were distributed throughout the brain and extensively in the diencephalon. MT-ir neurons and fibers were predominantly located within the nucleus supraopticus, pars ventralis (SOv), nucleus preopticus medialis (POM), nucleus ventrolateralis thalami (VLT), nucleus paraventricularis magnocellularis (PVN), and regio lateralis hypothalami (LHy), suggesting that MT neurons in these nuclei might be involved in the reproductive activities and/or parental behavior in the male chickens. In addition, the numbers of MT-ir neurons within the SOv and POM were significantly higher than those of the VLT, PVN, and LHy. More importantly, the number of MT-ir neurons in the SOv was high in the male brain when compared with the female brain, indicating that the MTergic system in the SOv might play a significant role in male reproductive activities in this equatorial species.

  • effects of nest deprivation on hypothalamic Mesotocin in incubating native thai hens gallus domesticus
    Acta Histochemica, 2017
    Co-Authors: Panpradap Sinpru, Mohamed El E Halawani, Tom E Porter, Yupaporn Chaiseha
    Abstract:

    Abstract Avian Mesotocin (MT) is homologous to oxytocin in mammals. Native Thai chickens ( Gallus domesticus ) strongly express maternal behaviors including incubation and rearing. However, the role of MT during incubation behavior has never been studied. The objective of this study was to determine the physiological function(s) of the MTergic system in incubation behavior in native Thai chickens. The brains were collected from incubating (INC) and nest-deprived (ND) hens at different time points (days 3, 6, 8, 10, 14, 18, and 21; n = 6). Immunohistochemistry technique was used to compare the numbers of MT-immunoreactive (-ir) neurons between the INC and ND hens within the Nucleus supraopticus, pars ventralis (SOv), Nucleus preopticus medialis (POM), and Nucleus paraventricularis magnocellularis (PVN). The results revealed that the numbers of MT-ir neurons within the SOv, POM, and PVN remained high during the incubating stage. The number of MT-ir neurons in the SOv was lower than that of the POM and PVN. Disruption of incubation behavior by nest deprivation caused the numbers of MT-ir neurons within the SOv, POM, and PVN to decrease throughout the observation periods. For the first time, this study demonstrates that the MTergic system within the SOv, POM, and PVN may be involved with incubation behavior. In addition, these results further suggest that the MTergic neurons in these nuclei are not only regulated by rearing behavior but also might have a role in the initiation and maintenance of incubation behavior in this tropical species.

  • Mesotocin and maternal care of chicks in native thai hens gallus domesticus
    Hormones and Behavior, 2013
    Co-Authors: Duangsuda Chokchaloemwong, Nattiya Prakobsaeng, Natagarn Sartsoongnoen, Sunantha Kosonsiriluk, Mohamed El E Halawani, Yupaporn Chaiseha
    Abstract:

    Abstract Oxytocin (OT) is known to induce and regulate maternal behaviors in mammals via the supraoptic nucleus and paraventricular nucleus (PVN), whereas the function of Mesotocin (MT; the avian homolog of OT) is poorly understood in birds. To elucidate the association of MT and the regulation of maternal behaviors in birds, we studied changes in the number of MT-immunoreactive (ir) neurons in native Thai chickens using immunohistochemistry. We observed that MT-ir neurons and fibers appeared in discrete regions located close to the third ventricle from the level of the preoptic area through the anterior hypothalamus with an abundance observed in the nucleus supraopticus, pars ventralis (SOv), nucleus preopticus medialis (POM), and PVN. The number of MT-ir neurons was low in the SOv, POM, and PVN of non-laying hens, but it increased gradually when the hens entered the laying stage, and peaked in incubating and rearing hens. We compared the number of MT-ir neurons in the SOv, POM, and PVN of native Thai hens rearing chicks (R) with that of non-rearing chicks (NR). The number of MT-ir neurons was high in the R hens, but low in the NR hens in these nuclei. For the first time, these results indicate that the association between the MT neurons and the presence of chicks might, in part, play a role in the neuroendocrine reorganization to establish and maintain maternal behaviors in native Thai chickens. MTergic activity is likely related to the contribution of rearing behavior in this equatorial precocial species.

R T Gemmell - One of the best experts on this subject based on the ideXlab platform.

  • Mesotocin and oxytocin in the brain and plasma of an australian marsupial the northern brown bandicoot isoodon macrourus
    Comparative Biochemistry and Physiology Part A: Physiology, 1992
    Co-Authors: Ross A D Bathgate, Conrad Sernia, R T Gemmell
    Abstract:

    Abstract 1. 1. Mesotocin (MT) and oxytocin (OT) were measured in the brain and plasma of bandicoots using reverse phase high performance liquid chromatography and specific radioimmunoassays. 2. 2. MT and OT were found in the pituitary (1.25 ± 0.10 μg/MT; 0.725 ± 0.077 μg/OT) and hypothalamus (38.37 ± 6.46 ng/MT; 19.1 ± 4.61 ng/OT). Smaller amounts were present in the cerebral cortex. 3. 3. Basal plasma concentrations ranged from 1.5 to 8.1 pg/ml for both peptides (N = 14) and were elevated by stress. 4. 4. It was concluded that both MT and OT are secreted by the bandicoot brain and that stress stimulates secretion.

  • Mesotocin in the brain and plasma of an australian marsupial the brushtail possum trichosurus vulpecula
    Neuropeptides, 1990
    Co-Authors: Ross A D Bathgate, Conrad Sernia, R T Gemmell
    Abstract:

    Oxytocic peptides extracted from the brain and plasma of the brushtail possum, Trichosurus vulpecula, were separated by reverse-phase high pressure lipid chromatography (HPLC) and quantified by specific radioimmunoassays for oxytocin (OT) and Mesotocin (MT). The pituitary, hypothalamus and cerebral cortex were found to contain MT only in quantities of 3.9 ± 0.2 (SE) ug, 17.6 ± 0.6 ng and 21.0 ± 2.6 ng respectively. The plasma concentration of MT varied according to the degree of stress of the possum. In anaesthetized animals values of 39.7 ± 9.7 pg/ml (11 males) and 31.5 ± 12.9 pg/ml (6 females) were obtained; in four conscious catheterized animals, 9.4 ± 6.3 pg/ml. Samples taken from three anaesthetized animals during exsanguination contained 271 ± 102 (SD) pg MT/ml. It was concluded that hypothalamic and extra-hypothalamic MT is present in the marsupial brain and that as in placental mammals, stress stimulates the secretion of Mesotocin.

Jae Young Seong - One of the best experts on this subject based on the ideXlab platform.

  • vasotocin and Mesotocin stimulate the biosynthesis of neurosteroids in the frog brain
    The Journal of Neuroscience, 2006
    Co-Authors: Jean Luc Dorego, Sujata Acharjee, Hyuk Bang Kwon, Jae Young Seong, Ludovic Galas, David Alexandre, Patrice Bizet, Arlette Burlet, Van Luuthe, Georges Pelletier
    Abstract:

    The neurohypophysial nonapeptides vasopressin (VP) and oxytocin (OT) modulate a broad range of cognitive and social activities. Notably, in amphibians, vasotocin (VT), the ortholog of mammalian VP, plays a crucial role in the control of sexual behaviors. Because several neurosteroids also regulate reproduction-related behaviors, we investigated the possible effect of VT and the OT ortholog Mesotocin (MT) in the control of neurosteroid production. Double immunohistochemical labeling of frog brain sections revealed the presence of VT/MT-positive fibers in close proximity of neurons expressing the steroidogenic enzymes 3β-hydroxysteroid dehydrogenase/Δ5-Δ4 isomerase (3β-HSD) and cytochrome P450 17α-hydroxylase/c17, 20-lyase (P450C17). High concentrations of VT and MT receptor mRNAs were observed in diencephalic nuclei containing the 3β-HSD and P450C17 neuronal populations. Exposure of frog hypothalamic explants to graded concentrations of VT or MT produced a dose-dependent increase in the formation of progesterone, 17-hydroxypregnenolone, 17-hydroxyprogesterone, and dehydroepiandrosterone. The stimulatory effect of VT and MT on neurosteroid biosynthesis was mimicked by VP and OT, as well as by a selective V1b receptor agonist, whereas V2 and OT receptor agonists had no effect. VT-induced neurosteroid production was completely suppressed by selective V1a receptor antagonists and was not affected by V2 and OT receptor antagonists. Concurrently, the effect of MT on neurosteroidogenesis was markedly attenuated by selective OT and V1a receptor antagonists but not by a V2 antagonist. The present study provides the first evidence for a regulatory effect of VT and MT on neurosteroid biosynthesis. These data suggest that neurosteroids may mediate some of the behavioral actions of VT and MT.

  • Molecular cloning, pharmacological characterization, and histochemical distribution of frog vasotocin and Mesotocin receptors
    Journal of Molecular Endocrinology, 2004
    Co-Authors: Sujata Acharjee, Hubert Vaudry, Jean Luc Do-rego, Da Young Oh, Jung Sun Moon, Hyuk Bang Kwon, Jae Young Seong
    Abstract:

    The neurohypophysial nonapeptides vasotocin (VT) and Mesotocin (MT) are the amphibian counterparts of arginine vasopressin (AVP) and oxytocin (OT). We have here reported the cloning and functional characterization of the receptors for vasotocin (VTR) and Mesotocin (MTR) in two species of frog, Rana catesbeiana and Rana esculenta. The frog VTR and MTR cDNAs encode proteins of 419 and 384 amino acids respectively. Frog VTR exhibits a high degree of sequence identity with the mammalian AVP-1a (V1a) receptor while the frog MTR possesses a high degree of sequence identity with the mammalian OT receptor. Activation of VTR induced both c-fos promoter- and cAMP-responsive element (CRE)-driven transcriptional activities, while activation of MTR induced c-fos promoter-driven transcriptional activity but failed to evoke CRE-driven transcriptional activity, suggesting differential G protein coupling between VTR and MTR. The VTR exhibited the highest sensitivity for VT followed by OT.AVP

  • molecular cloning pharmacological characterization and histochemical distribution of frog vasotocin and Mesotocin receptors
    Journal of Molecular Endocrinology, 2004
    Co-Authors: Sujata Acharjee, Hubert Vaudry, Jung Sun Moon, Hyuk Bang Kwon, Jean Luc Dorego, Da Young Oh, Jae Young Seong
    Abstract:

    The neurohypophysial nonapeptides vasotocin (VT) and Mesotocin (MT) are the amphibian counterparts of arginine vasopressin (AVP) and oxytocin (OT). We have here reported the cloning and functional characterization of the receptors for vasotocin (VTR) and Mesotocin (MTR) in two species of frog, Rana catesbeiana and Rana esculenta. The frog VTR and MTR cDNAs encode proteins of 419 and 384 amino acids respectively. Frog VTR exhibits a high degree of sequence identity with the mammalian AVP-1a (V1a) receptor while the frog MTR possesses a high degree of sequence identity with the mammalian OT receptor. Activation of VTR induced both c-fos promoter- and cAMP-responsive element (CRE)-driven transcriptional activities, while activation of MTR induced c-fos promoter-driven transcriptional activity but failed to evoke CRE-driven transcriptional activity, suggesting differential G protein coupling between VTR and MTR. The VTR exhibited the highest sensitivity for VT followed by OT.AVP