Linked Life Data

3120813

Source:http://linkedlifedata.com/resource/pubmed/id/3120813

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1988-2-10
pubmed:abstractText
In this study, we monitored episodic luteinizing hormone (LH) secretion throughout development in eight April-born ewe lambs to determine if a change in LH pulse patterns preceded first ovulation at puberty. LH pulses were measured in samples collected every 12 min for 6 h once in July, twice a month from 22 August to 2 October, and then weekly until puberty. Progesterone concentrations, measured in samples taken 3/wk, were used as an index of first ovulation, which occurred at 29.3 +/- 0.7 wk of age. LH pulse frequencies throughout most of this period ranged from 0 to 2 pulses/6 h, with no change over time. However, during the week prior to the first progesterone rise, there was a significant increase in pulse frequency to a level seen during the follicular phase in post-pubertal lambs. This increase in pulse frequency was evident in 7 of 8 lambs; pulses were not analyzed in the last lamb because samples were taken during the LH surge. In contrast, LH pulse amplitude did not increase prior to puberty. In fact, pulse amplitude declined linearly during the 3 wk before first ovulation and then increased during the follicular phase in post-pubertal animals. These results support the hypothesis that an increase in the frequency of episodic LH secretion is a key event leading to the onset of ovarian cycles in the lamb. Whether an increase in pulse amplitude is also necessary remains unclear. If so, it must occur just before the LH surge, since it was not detected in any samples taken before puberty in this study.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0006-3363
pubmed:author
pubmed:issnType
Print
pubmed:volume
37
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
755-61
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1987
pubmed:articleTitle
Changes in episodic luteinizing hormone secretion leading to puberty in the lamb.
pubmed:affiliation
Department of Physiology, West Virginia University, Morgantown 26506.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.