Linked Life Data

9835373

Source:http://linkedlifedata.com/resource/pubmed/id/9835373

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1-4
pubmed:dateCreated
1999-1-28
pubmed:abstractText
Seasonal changes in testicular morphology and blood plasma concentrations of LH, testosterone, and prolactin are described for captive male emus in southwestern Australia. Testicular mass and testicular testosterone did not differ between the non-breeding (spring-summer) and the breeding (autumn-winter) seasons. Nevertheless, the testes obtained in the breeding season (May and August) were nearly two fold greater in mass than those collected in the non-breeding season (October and February). The highest testicular concentrations of testosterone were observed in February and lowest in October, while the values during the breeding season were intermediate. The patterns of histological changes in the testes also indicate that emus breed over the autumn-winter months. Tubule diameter was larger in the breeding season than in the non-breeding season, whereas the relative volume of the interstitium was larger in the non-breeding and smaller in the breeding season. Moreover, during the autumn and winter months, plasma LH and testosterone concentrations were high. Outside this period, in spring and summer, the concentrations of these hormones were low. Prolactin concentrations rose around the winter solstice, after the initial increases in plasma LH and testosterone. The end of the breeding season, in early spring, was marked by a gradual decrease in plasma LH concentrations but a rapid fall in testosterone concentrations. Prolactin concentrations continued to increase and peaked near the spring equinox, several weeks after the breeding season ended, and then decreased to reach baseline values by mid-summer. These testicular and endocrine changes are consistent with observations that the emu is a short-day breeder in southwestern Australia. Reproductive activity in the male begins soon after the summer solstice, well in advance of the development of suitable breeding conditions, and is then terminated in spring before food resources become limited by the onset of the dry season.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0378-4320
pubmed:author
pubmed:issnType
Print
pubmed:volume
53
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
143-55
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Endocrine and testicular changes in a short-day seasonally breeding bird, the emu (Dromaius novaehollandiae), in southwestern Australia.
pubmed:affiliation
Faculty of Agriculture (Animal Science), The University of Western Australia, Nedlands, Australia. imalecki@agric.uwa.edu.au
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't