Linked Life Data

8912237

Source:http://linkedlifedata.com/resource/pubmed/id/8912237

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1997-2-10
pubmed:abstractText
Two experiments were designed to determine whether gonadal steroids during the estrous cycle may modify the characteristics of the plasma melatonin rhythm. In the first experiment, 12 ovariectomized estradiol-treated ewes were used and exposed to constant short days. The experimental design was a latin square to distinguish between steroid treatments and individual effects on melatonin secretion. Twenty four hours before the bleeding period (hourly during 20 hr) and with a 1 week interval, animals were treated with a) additional subcutaneous estradiol implants, b) progesterone devices, or c) control. In the second experiment, nine ewes received a treatment combining fluorogestone acetate devices and pregnant mare serum gonadotrophin to induce synchronous ovulations. Samples for melatonin determination were obtained hourly for 13 hr at three stages of estrous cycle: follicular phase, early luteal phase, and late luteal phase. Ovarian activity was monitored by taking daily samples for progesterone analysis and ovulation rate was determined by laparoscopy. Duration and mean melatonin plasma concentrations of the elevation were calculated for each ewe and each night and analysed by latin square test (experiment 1) or ANOVA (experiment 2). Melatonin concentrations of elevation and duration of elevation were not significantly affected by hormonal treatments or by phase of estrous cycle. A strong individual effect was detected (P < 0.01) for both parameters in both experiments. It was concluded that melatonin secretion is unaffected by steroid administration or by phase of estrous cycle. The existence of very high inter-individual variation suggest that both parameters are individual characteristics of each animal which may have a strong genetic basis.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0742-3098
pubmed:author
pubmed:issnType
Print
pubmed:volume
21
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
114-20
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Characteristics of the plasma melatonin rhythm are not modified by steroids during the estrous cycle in IIe-de-France ewes.
pubmed:affiliation
INRA Neuroedocrinologie Sexuelle, Physiologie de la Reproduction, Nouzilly, France.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't