Linked Life Data

7798017

Source:http://linkedlifedata.com/resource/pubmed/id/7798017

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1995-8-3
pubmed:abstractText
Developmental increases in serum LH were assessed in female rhesus monkeys to test the hypotheses that (1) the final stages of puberty are characterized by a decrease in hypersensitivity to oestradiol negative feedback of LH and (2) that increases in IGF-I secretion accelerate this decrease in hypersensitivity. In order to test the first hypothesis, serum LH in the absence of oestradiol and in response to three doses of oestradiol were compared between ovariectomized adult (n = 6) and adolescent female monkeys (control group; n = 6). The control females were not treated with oestradiol until serum LH had risen to within the 95% confidence interval of serum LH observed in ovariectomized adults. Doses of oestradiol achieved serum levels of approximately 80 ('low'), 160 ('intermediate'), and 250 ('high') pmol/l. For control group females, treatment with the next higher dose of oestradiol was not initiated until serum LH was no longer suppressed by the lower dose. Treatment with oestradiol produced a dose-dependent suppression in serum LH in adults. In contrast, low-dose oestradiol maximally suppressed serum LH throughout the initial treatment period in the control group compared with the adult females. The low oestradiol dose effectively suppressed serum LH throughout the study period in 4/6 of the control group and became ineffective at suppressing LH after 8 months of treatment in 2/6 control group females. Initiation of the intermediate dose of oestradiol to these females again maximally suppressed LH compared with adult females. In order to determine whether IGF-I regulates this change in hypersensitivity to oestradiol negative feedback, a second group of ovariectomized, adolescent monkeys (n = 6) were treated chronically with IGF-I to elevate serum IGF-I levels above those of control group females. Using the same protocol described for the control females, developmental changes in serum LH in the absence of oestradiol and in response to oestradiol negative feedback were evaluated. Treatment with IGF-I had no effect on the initial increases in serum LH occurring in the absence of oestradiol. In contrast, the decrease in hypersensitivity to the negative feedback effects of the low oestradiol dose was significantly accelerated in IGF-I-treated females, as the interval from the initiation of treatment to the point at which serum LH was no longer suppressed was shorter in IGF-I-treated (4.4 +/- 0.7 months; mean +/- S.E.M.) compared with control group females (8.4 +/- 1.9 months).(ABSTRACT TRUNCATED AT 400 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0022-0795
pubmed:author
pubmed:issnType
Print
pubmed:volume
145
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
121-30
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
IGF-I administration advances the decrease in hypersensitivity to oestradiol negative feedback inhibition of serum LH in adolescent female rhesus monkeys.
pubmed:affiliation
Yerkes Primate Research Center of Emory University, Lawrenceville, Georgia 30243, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.