Prolactin secretion in lactating mares before and after treatment with bromocriptine

The effect of treating lactating mares with the dopamine agonist bromocriptine was investigated. Seven pony and 4 Thoroughbred lactating mares were given a single intramuscular (i.m.) injection of 100 mg bromocriptine between Days 18 and 28 after foaling when the secretion rate of prolactin was elev...

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Bibliographic Details
Published inJournal of reproduction and fertility. Supplement Vol. 44; p. 551
Main Authors Neuschaefer, A, Bracher, V, Allen, W R
Format Journal Article
LanguageEnglish
Published England 1991
Subjects
Animals
Bromocriptine - pharmacology
Female
Horses - physiology
Lactation - physiology
Luteinizing Hormone - blood
Ovary - drug effects
Pituitary Gland - drug effects
Pregnancy
Prolactin - blood
Prolactin - secretion
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Summary:The effect of treating lactating mares with the dopamine agonist bromocriptine was investigated. Seven pony and 4 Thoroughbred lactating mares were given a single intramuscular (i.m.) injection of 100 mg bromocriptine between Days 18 and 28 after foaling when the secretion rate of prolactin was elevated. Prolactin and luteinizing hormone (LH) concentrations were measured in serial peripheral plasma samples taken before and after the treatment and, in 5 of the pony mares, levels of these hormones were also measured in pituitary venous effluent obtained by cannulation of the cavernous sinus. In all the mares, prolactin concentrations fell sharply after treatment (Day 0) and they started to increase again on Day 2 in the Thoroughbreds and Day 3 in the ponies. Pituitary LH secretion rate also declined significantly for 2 days after treatment but there were no measureable influences on cyclic ovarian activity.
ISSN:0449-3087