Linked Life Data

9528928

Source:http://linkedlifedata.com/resource/pubmed/id/9528928

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1998-4-14
pubmed:abstractText
Melatonin transduces the effect of day length on LH secretion by acting on the hypothalamus. However, the precise hypothalamic site is unknown. Two studies were undertaken to clarify where melatonin acts in the hypothalamus. Using autoradiographic methods, the hypothalami of 5 ewes were screened to determine whether specific regional densities in melatonin binding existed. A higher density of binding was observed in the premammillary area of the hypothalamus (PMH) (3- to 5-fold higher than the rest of the hypothalamus). This binding area is delimited rostrally by the infundibular recess, caudally by the mammillary bodies, dorsally by the fornix, and ventrally by the base of the brain; and it encompasses the premammillary and tuberomammillary nuclei. To test the functional importance of the identified area, 3 groups of animals received bilateral melatonin microimplants: 1) in the PMH (n = 11); 2) in the anterior/mediobasal hypothalamus (AH/MBH; n = 8); and 3) sham-operated animals received empty microimplants in the PMH (SHAM; n = 6). All ewes were ovariectomized and treated s.c. with a 20-mm SILASTIC brand capsule of estradiol and exposed to long days (16-h light, 8-h dark). At the end of the 80-day experiment, no animal of the SHAM group and only 2 of the 8 ewes of the AH/MBH group displayed a stimulation of LH secretion. In contrast, melatonin implanted in the PMH stimulated LH secretion in 10 of the 11 ewes on day 44.5 +/- 5.3 (mean +/- SEM). ANOVA revealed that the changes in LH secretion were not different between the SHAM and the AH/MBH groups but the PMH group differed from the other 2 groups (P < 0.0001). This study suggests that the PMH is an important target for melatonin to regulate reproductive activity.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0013-7227
pubmed:author
pubmed:issnType
Print
pubmed:volume
139
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1508-16
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Evidence that melatonin acts in the premammillary hypothalamic area to control reproduction in the ewe: presence of binding sites and stimulation of luteinizing hormone secretion by in situ microimplant delivery.
pubmed:affiliation
Institut National de la Recherche Agronomique, Laboratoire de Neuroendocrinologie Sexuelle, URA Centre National de la Recherche Scientifique 1291, Nouzilly, France. malpaux@tours.inra.fr
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't