Induced Lactation with a Dopamine Antagonist in Mares: Different Responses between Ovariectomized and Intact Mares
| Autor: | Yves Combarnous, G. Duchamp, Peter Daels, P. Nagy, Daniel Guillaume, Nadine Martinat, Pascale Chavatte-Palmer |
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| Rok vydání: | 2003 |
| Předmět: |
endocrine system
medicine.medical_specialty 040301 veterinary sciences animal diseases Biology Dopamine agonist 0403 veterinary science Endocrinology Lactation Internal medicine Follicular phase medicine reproductive and urinary physiology urogenital system 0402 animal and dairy science Dopamine antagonist 04 agricultural and veterinary sciences 040201 dairy & animal science Prolactin 3. Good health medicine.anatomical_structure Ovariectomized rat Animal Science and Zoology sense organs Luteinizing hormone Sulpiride Biotechnology medicine.drug |
| Zdroj: | Reproduction in Domestic Animals. 38:394-400 |
| ISSN: | 0936-6768 |
| DOI: | 10.1046/j.1439-0531.2003.00454.x |
| Popis: | The aim of this study was to compare the effects of treatment with repeated injections of sulpiride (a dopamine D2 antagonist) on prolactin secretion and induced lactation in ovariectomized and intact adult mares and to verify if this induction was possible at the beginning and at the end of the birth season. Two experiments were carried out in September [experiment (expt) 1], and in March (expt 2), in France (48� N). In expt 1, three groups of five mares were tested: intact-control, intact-treated and ovariectomized-treated mares. In expt 2, mares previously subjected to artificial photoperiod were assigned in two groups: four intact-control and five intact-treated mares. The cyclicity of intact mares was previously synchronized with PGF2a injections, then all the mares were in the follicular phase at the beginning of treatment. Sulpiride was intramuscularly injected (0.5 mg/kg of BW), twice a day. Mares were milked at 7:30, 11:45, 16:00 and 20:15 hours. Blood samples were collected every day during the treatment for progesterone, total oestrogen and prolactin assays. In the two experiments, only treated intact mares produced milk, with a large inter-animal variability. Prolactin increase after sulpiride treatment was not so great in the ovariectomized-treated mares as in the intact-treated mares. The total correlations between prolactin, progesterone, oestrogen plasma concentrations and daily milk production were significant (0.57, 0.25, 0.17 respectively). This induction of lactation can be performed during the entire birth season in intact mares, but not in ovariectomized mares, indicating that steroids are necessary for this induction in mares treated by dopamine D2 antagonist. |
| Databáze: | OpenAIRE |
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