Linked Life Data

2671236

Source:http://linkedlifedata.com/resource/pubmed/id/2671236

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1989-10-3
pubmed:abstractText
Two experiments were conducted with ovariectomized and hypothalamo-pituitary disconnected (HPD) ewes to ascertain the pattern of inputs, to the pituitary gland, of gonadotrophin-releasing hormone (GnRH) necessary for the full expression of an oestrogen-induced LH surge. The standard GnRH replacement to these sheep was to give pulses of 250 ng (i.v.) every 2h; at the onset of experimentation, pulses were given hourly. In experiment 1, groups of sheep (n = 7) were given an i.m. injection of 50 micrograms oestradiol benzoate, and after 10 h the GnRH pulse frequency or pulse amplitude was doubled. Monitoring of plasma LH concentrations showed that a doubling of pulse frequency produced a marked increase in baseline values, whereas a doubling of amplitude had little effect on the LH response. In a second experiment, ovariectomized HPD sheep that had received hourly pulses of GnRH for 16 h after an i.m. injection of oil or 50 micrograms oestradiol benzoate were given either a 'bolus' (2.25 micrograms GnRH) or a 'volley' (500 ng GnRH pulses 10 min apart for 30 min, plus a 500 ng pulse 15 min later). Both groups then received GnRH pulses (250 ng) every 30 min for the next 13 h. Oestrogen enhanced the LH responses to the GnRH treatments, and the amount of LH released was similar in ovariectomized HPD ewes given oestrogen plus bolus or volley GnRH treatments and ovariectomized hypothalamo-pituitary intact ewes given oestrogen. These results suggest that the oestrogen-induced LH surge is initiated by a 'signal' pattern of GnRH secretion from the hypothalamus.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0022-0795
pubmed:author
pubmed:issnType
Print
pubmed:volume
122
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
127-34
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
The oestrogen-induced surge of LH requires a 'signal' pattern of gonadotrophin-releasing hormone input to the pituitary gland in the ewe.
pubmed:affiliation
Medical Research Centre, Prince Henry's Hospital, Melbourne, Victoria, Australia.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't