Linked Life Data

7592093

Source:http://linkedlifedata.com/resource/pubmed/id/7592093

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
1995-11-30
pubmed:abstractText
We hypothesized that estradiol-17 beta (E2) was capable of stimulating an LH surge in 6-mo-old heifers immunized against growth hormone-releasing factor (GRFi). To test this hypothesis Angus x Simmental heifers were immunized against GRF (n = 11) or human serum albumin (HSAi) (n = 6) at 113 d of age. Heifers were injected i.m. with 500 micrograms of E2 at 172 d of age. To characterize the LH response, samples were collected at frequent intervals for 1 h before and 32 h after E2. To assess ovarian responses, real-time ultrasonography was performed from d 9 to 20, and serum progesterone was evaluated from d 6 to 25 after E2, then weekly for 13 wk. Exogenous E2 stimulated (P < .001) LH surges, preceded by negative E2 feedback that decreased serum LH, in all GRFi and HSAi heifers. During the negative feedback period, serum LH was greater (P < .001), and the change in LH from before to after E2 was lower (P < .05), in GRFi than in HSAi heifers. Puberty occurred in 7/17 heifers within 66 d after receiving E2. We conclude that GRFi does not impair the release of an E2-induced LH surge, but it does decrease hypothalamo-hypophyseal sensitivity to the inhibitory effect of E2.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0021-8812
pubmed:author
pubmed:issnType
Print
pubmed:volume
73
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2071-8
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Endocrine and ovarian responses to exogenous estradiol-17 beta in 6-month-old heifers previously immunized against growth hormone-releasing factor.
pubmed:affiliation
Department of Animal Science, North Carolina State University, Raleigh, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't