Linked Life Data

7987370

Source:http://linkedlifedata.com/resource/pubmed/id/7987370

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1995-1-9
pubmed:abstractText
Hypothalamo-pituitary inhibition of reproductive function during undernutrition is well known, however, the physiological mechanisms leading to suppression of gonadotrophin secretion are not clear. A variety of studies have indicated that testicular negative feedback on LH secretion is enhanced during food restriction. To evaluate directly the suppression by endogenous androgens on hypothalamic GnRH pulse generator activity during food restriction and examine the mechanism underlying the increased testicular steroidal feedback, we examined (1) circulating bioactive LH (bLH) levels in response to selective cerebral androgen blockade by intraventricular administration of an androgen receptor antagonist (hydroxyflutamide, SCH 16423) and (2) the binding capacity and affinity of androgen receptors in medio-basal hypothalamus, pituitary and prostate during undernutrition of intact mature male rats. Hydroxyflutamide (20 micrograms in 10 microliters vehicle), but not vehicle alone, markedly increased bLH levels in both food restricted and ad-lib fed rats. However, the faster (geometric mean 11.4 vs 27.7 min) and greater (47.2 vs 21.9 ng/ml) increase in bLH level in food restricted compared with ad-lib fed controls demonstrates an enhanced sensitivity to blockade of androgenic negative feedback during undernutrition. Food restriction increased androgen receptor binding capacity in pituitary (3.36 vs 0.77 fmol/mg protein) but not in medio-basal hypothalamus or prostate while binding affinity was unchanged by undernutrition in all 3 tissues. These studies reveal that undernutrition both enhances tonic, androgen receptor-mediated feedback suppression of GnRH secretion and increases in pituitary (but not hypothalamic) androgen receptor numbers to cause inhibition of LH secretion.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0953-8194
pubmed:author
pubmed:issnType
Print
pubmed:volume
6
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
397-402
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Androgen receptor function during undernutrition.
pubmed:affiliation
Department of Obstetrics & Gynaecology, University of Sydney, Australia.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't