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Registro Completo |
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Biblioteca(s): |
Embrapa Caprinos e Ovinos. |
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Data corrente: |
22/06/2017 |
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Data da última atualização: |
22/06/2017 |
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Autoria: |
BASSETT, J. M.; CURTIS, N.; HANSON, C.; WEEDING C. M. |
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Título: |
Effects of altered photoperiod or maternal melatonin administration on plasma prolactin concentrations in fetal lambs. |
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Ano de publicação: |
1989 |
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Fonte/Imprenta: |
Journal of Endocrinology, v. 122, n. 3, p. 633-644, Jul. 1989. |
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DOI: |
0.1677/joe.0.1220633 |
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Idioma: |
Inglês |
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Conteúdo: |
Abstract: During winter (December to March), when late-pregnant ewes were maintained under an artificial long-day photoperiod (16 h light) for 3 weeks or more before insertion of fetal vascular cannulae between 118 and 120 days of gestation (full term, 147 days), plasma prolactin concentrations in their fetal lambs were significantly increased throughout the last 3 weeks of gestation in comparison with values in similar aged fetuses from ewes experiencing only the natural short-day (less than 9 h light) winter photoperiod. When additional lighting was given only after vascular cannulation, fetal plasma prolactin increased steadily from low values, characteristic of winter pregnancies, to high values, characteristic of long-day (16 h light:8 h darkness) pregnancies. Maternal plasma prolactin concentrations changed in a similar way. During summer pregnancies (greater than 16 h light), plasma prolactin in fetal lambs was significantly reduced within 48 h when ewes were given melatonin by i.v. infusion for 14 h each night to simulate the winter duration of the nocturnal increase in plasma melatonin. Maternal plasma prolactin concentrations also decreased significantly when melatonin was given for 3 weeks, but not in a shorter experiment. Increases in fetal plasma prolactin were proportional to the basal prolactin concentration in fetuses injected i.v. with TRH or a dopaminergic antagonist, metoclopramide, to assess how photoperiod influenced the responsiveness of prolactin secretion to acute stimulation. The results confirm that photoperiod, rather than developmental maturity, is the principal determinant of plasma prolactin in the fetal lamb during the last third of gestation, and provide evidence that photoperiodic information is transmitted to the fetus through the diurnal rhythm of melatonin in the ewe. MenosAbstract: During winter (December to March), when late-pregnant ewes were maintained under an artificial long-day photoperiod (16 h light) for 3 weeks or more before insertion of fetal vascular cannulae between 118 and 120 days of gestation (full term, 147 days), plasma prolactin concentrations in their fetal lambs were significantly increased throughout the last 3 weeks of gestation in comparison with values in similar aged fetuses from ewes experiencing only the natural short-day (less than 9 h light) winter photoperiod. When additional lighting was given only after vascular cannulation, fetal plasma prolactin increased steadily from low values, characteristic of winter pregnancies, to high values, characteristic of long-day (16 h light:8 h darkness) pregnancies. Maternal plasma prolactin concentrations changed in a similar way. During summer pregnancies (greater than 16 h light), plasma prolactin in fetal lambs was significantly reduced within 48 h when ewes were given melatonin by i.v. infusion for 14 h each night to simulate the winter duration of the nocturnal increase in plasma melatonin. Maternal plasma prolactin concentrations also decreased significantly when melatonin was given for 3 weeks, but not in a shorter experiment. Increases in fetal plasma prolactin were proportional to the basal prolactin concentration in fetuses injected i.v. with TRH or a dopaminergic antagonist, metoclopramide, to assess how photoperiod influenced the responsiveness of prolactin secre... Mostrar Tudo |
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Palavras-Chave: |
Fetal Exchange; Foetus; Maternal behaviour; Releasing Hormone. |
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Thesaurus Nal: |
Melatonin; Metabolism; metoclopramide; Pharmacology; Pregnancy; Prolactin; Sheep; Thyrotropin. |
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Categoria do assunto: |
L Ciência Animal e Produtos de Origem Animal |
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Marc: |
LEADER 02703naa a2200313 a 4500
001 2071352
005 2017-06-22
008 1989 bl uuuu u00u1 u #d
024 7 $a0.1677/joe.0.1220633$2DOI
100 1 $aBASSETT, J. M.
245 $aEffects of altered photoperiod or maternal melatonin administration on plasma prolactin concentrations in fetal lambs.
260 $c1989
520 $aAbstract: During winter (December to March), when late-pregnant ewes were maintained under an artificial long-day photoperiod (16 h light) for 3 weeks or more before insertion of fetal vascular cannulae between 118 and 120 days of gestation (full term, 147 days), plasma prolactin concentrations in their fetal lambs were significantly increased throughout the last 3 weeks of gestation in comparison with values in similar aged fetuses from ewes experiencing only the natural short-day (less than 9 h light) winter photoperiod. When additional lighting was given only after vascular cannulation, fetal plasma prolactin increased steadily from low values, characteristic of winter pregnancies, to high values, characteristic of long-day (16 h light:8 h darkness) pregnancies. Maternal plasma prolactin concentrations changed in a similar way. During summer pregnancies (greater than 16 h light), plasma prolactin in fetal lambs was significantly reduced within 48 h when ewes were given melatonin by i.v. infusion for 14 h each night to simulate the winter duration of the nocturnal increase in plasma melatonin. Maternal plasma prolactin concentrations also decreased significantly when melatonin was given for 3 weeks, but not in a shorter experiment. Increases in fetal plasma prolactin were proportional to the basal prolactin concentration in fetuses injected i.v. with TRH or a dopaminergic antagonist, metoclopramide, to assess how photoperiod influenced the responsiveness of prolactin secretion to acute stimulation. The results confirm that photoperiod, rather than developmental maturity, is the principal determinant of plasma prolactin in the fetal lamb during the last third of gestation, and provide evidence that photoperiodic information is transmitted to the fetus through the diurnal rhythm of melatonin in the ewe.
650 $aMelatonin
650 $aMetabolism
650 $ametoclopramide
650 $aPharmacology
650 $aPregnancy
650 $aProlactin
650 $aSheep
650 $aThyrotropin
653 $aFetal Exchange
653 $aFoetus
653 $aMaternal behaviour
653 $aReleasing Hormone
700 1 $aCURTIS, N.
700 1 $aHANSON, C.
700 1 $aWEEDING C. M.
773 $tJournal of Endocrinology$gv. 122, n. 3, p. 633-644, Jul. 1989.
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Registro original: |
Embrapa Caprinos e Ovinos (CNPC) |
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 | Acesso ao texto completo restrito à biblioteca da Embrapa Cerrados. Para informações adicionais entre em contato com cpac.biblioteca@embrapa.br. |
Registro Completo
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Biblioteca(s): |
Embrapa Cerrados. |
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Data corrente: |
11/08/1995 |
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Data da última atualização: |
05/03/2009 |
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Autoria: |
MILLER, S. E.; BECKER, V. O.; VELEZ-ANGEL, R. |
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Título: |
Podalia bolivasi (Lepidoptera: Mega lopygidae). |
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Ano de publicação: |
1995 |
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Fonte/Imprenta: |
Proceedings of Entomological Society of Washington, v.97, n.1, p.117-122, 1995. |
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Idioma: |
Inglês |
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Palavras-Chave: |
Fern; Palm; Palmeira; Podalia bolivari; Zygaenoidea. |
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Thesagro: |
Samambaia. |
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Thesaurus NAL: |
Megalopyge; Megalopygidae. |
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Categoria do assunto: |
-- |
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Marc: |
LEADER 00606naa a2200229 a 4500
001 1555989
005 2009-03-05
008 1995 bl --- 0-- u #d
100 1 $aMILLER, S. E.
245 $aPodalia bolivasi (Lepidoptera$bMega lopygidae).
260 $c1995
650 $aMegalopyge
650 $aMegalopygidae
650 $aSamambaia
653 $aFern
653 $aPalm
653 $aPalmeira
653 $aPodalia bolivari
653 $aZygaenoidea
700 1 $aBECKER, V. O.
700 1 $aVELEZ-ANGEL, R.
773 $tProceedings of Entomological Society of Washington$gv.97, n.1, p.117-122, 1995.
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