Linked Life Data

11459772

Source:http://linkedlifedata.com/resource/pubmed/id/11459772

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
2001-7-18
pubmed:abstractText
The peripubertal transition in male mammals is accompanied by a gradual decrease in sensitivity to the inhibitory effects exerted by gonadal hormones, such as T and E2. Here, we investigated the effects of chronic T and its metabolites, 5alpha-dihydrotestosterone and E2 on the hypothalamo-pituitary-gonadal axis at puberty. We also examined if T effects are distinct or mediated through its conversion to 5alpha-dihydrotestosterone or E2. Twenty-day-old male Siberian hamsters were sc implanted with a SILASTIC brand capsule containing varying doses of T, 5alpha-dihydrotestosterone, or E2. Several functional parameters of the hypothalamo-pituitary-gonadal axis were evaluated including hypothalamic GnRH concentration, pituitary and plasma FSH levels, pituitary FSH and LH mRNA, and testicular status. Our results showed that gonadal steroids inhibited puberty in a dose-dependent manner as evaluated by testes mass (undiluted steroid: T, 27 +/- 3 mg; 5alpha-dihydrotestosterone, 18 +/- 1 mg; and E2, 62 +/- 4 mg relative to cholesterol-implanted controls, 510 +/- 42 mg). Also, T decreased plasma FSH below detectable levels, but pituitary FSH concentration was unaffected (1.37 +/- 0.16 ng/microg protein) while E2-treated hamsters had normal plasma FSH levels (3.5 +/- 0.98 ng/ml) yet significantly lower pituitary FSH concentration (0.09 +/- 0.04 ng/microg protein). These results showed that the pathways of T and E2 action on the hypothalamo-pituitary-gonadal axis are distinct.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0013-7227
pubmed:author
pubmed:issnType
Print
pubmed:volume
142
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3309-16
pubmed:dateRevised
2010-4-12
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Testosterone and estrogen act via different pathways to inhibit puberty in the male Siberian hamster (Phodopus sungorus).
pubmed:affiliation
Department of Environmental, Population and Organismic Biology, University of Colorado, Boulder, Colorado 80309, USA. toni.pak@colorado.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't