Linked Life Data

2073999

Source:http://linkedlifedata.com/resource/pubmed/id/2073999

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1991-4-15
pubmed:abstractText
Testicular tissue collected at different stages of gonadal development was incubated with a pituitary extract (PE) from mature salmon. Three androgens (11-ketotestosterone, OT; 11 beta-hydroxytestosterone, OHT; and testosterone, T) and 17 alpha,20 beta-dihydroxyprogesterone (17-20 beta P) were quantified by radioimmunoassay in incubation media. OHT and OT were secreted in larger quantities than T and 17-20 beta P. The PE dose that evoked a half-maximal response (ED50), the ratios of maximum stimulated vs baseline secretion, and total testicular steroid output all changed during the reproductive cycle. Androgen secretion in response to PE was low in immature and spent fish, both in terms of ED50 and the ratio of maximum stimulated vs baseline secretion. This ratio increased in testes showing the first signs of maturation and remained elevated during rapid testicular growth, before reaching maximum values at full maturity. The lowest ED50 values were found at the end of spermatogenesis and during the peak spawning period. 17-20 beta P secretion could not be stimulated noticeably until the fish had entered the spawning period and, as opposed to androgens, remained stimulable in spent fish. ED50 values for 17-20 beta P ranged, without showing clear-cut variations, above those calculated for androgens. The changes in PE reactivity and steroid secretion capacity during the reproductive cycle are likely to contribute to the changes in circulating steroid concentrations and may allow modulations of testicular steroid production without large changes in circulating GTH levels.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0016-6480
pubmed:author
pubmed:issnType
Print
pubmed:volume
80
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
189-98
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Steroid secretion of rainbow trout testis in vitro: variation during the reproductive cycle.
pubmed:affiliation
Ruhr-Universität Bochum, Fakultät Biologie, Federal Republic of Germany.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't