Linked Life Data

10425459

Source:http://linkedlifedata.com/resource/pubmed/id/10425459

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1999-10-26
pubmed:abstractText
There is a sex difference in the hypothalamo-pituitary-adrenal (HPA) axis of many species, although there are sparse data on the sheep. In the present study we have compared the HPA axes of intact and gonadectomised adult male and female sheep at the level of the median eminence, pituitary and adrenal glands using a variety of in vitro approaches. The concentration of arginine vasopressin (AVP) was higher (P<0.01) in the median eminence of male than female sheep, and was also elevated by gonadectomy of either sex (P<0.01). The concentration of corticotrophin-releasing factor (CRF) in the median eminence did not differ between the sexes, but was also elevated in both sexes following gonadectomy (P<0.01). Anterior pituitary pro-opiomelanocortin mRNA concentrations were higher (P<0.05) in intact male sheep than in intact females, with the levels in gonadectomised animals of both sexes being intermediate. In contrast to this finding, basal ACTH secretion from anterior pituitary cells was higher (P<0.05) in cultures derived from female sheep than those from males, but gonadectomy was without effect. There was no effect of sex or gonadectomy on in vitro ACTH secretion in response to AVP, CRF or the combination of AVP and CRF, and in all cases the combination of AVP and CRF generated greater (P<0.0001) ACTH secretion than AVP alone. AVP alone was more effective (P<0.01) than CRF alone as an ACTH secretagogue. The adrenal glands were larger (P<0.05) in female than male sheep, with no effect of gonadectomy. Basal cortisol production was greatest (P<0.05) in cultures of adrenal cells from intact male sheep, though ACTH- and 8BrcAMP-induced cortisol production was greater in the cultures of cells from females (P=0.05); there were no effects of gonadectomy. Cultures of adrenocortical cells from male sheep had greater (P<0.05) basal cAMP production, but ACTH-stimulated cAMP production did not differ between any of the groups of animals. These findings show a range of differences in the HPA axis of male and female sheep. Furthermore, they suggest that the heightened activity of the axis in the female occurs primarily due to differences at the level of the adrenal gland, and that greater adrenal responsiveness of female animals is due to differences in the latter stages of steroidogenesis, rather than an effect on ACTH signal transduction at its receptor.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0022-0795
pubmed:author
pubmed:issnType
Print
pubmed:volume
162
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
215-25
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
The influence of sex and gonadectomy on the hypothalamo-pituitary-adrenal axis of the sheep.
pubmed:affiliation
Department of Physiology, Monash University, Clayton, Victoria, 3168 Australia.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't