Linked Life Data

33801

Source:http://linkedlifedata.com/resource/pubmed/id/33801

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1979-5-26
pubmed:abstractText
The importance of calcium in the ACTH-induced increase in adrenal mitochondrial pregnenolone synthesis was evaluated. In mitochondria prepared in the absence of EDTA and albumin, calcium enhanced the binding of cholesterol to cytochrome P-450 and subsequent pregnenolone synthesis. Although these effects of calcium were slightly greater in control than in ACTH-treated mitochondria, a sizeable effect of ACTH remained even at high calcium levels (500 micron). In mitochondria prepared from adrenals homogenized in fluid containing EDTA and albumin, ACTH-induced effects on pregnenolone synthesis were relatively poor unless calcium was added to the incubation mixture. High concentrations of added calcium (500 micron or greater) obviated the need for the labile protein required for ACTH-induced effects in intact mitochondria, presumably by disrupting mitochondria and allowing an "unrestrained" interaction of cholesterol with cytochrome P-450. Thus, cholesterol-rich mitochondria from ACTH plus cycloheximide-treated rats produced large amounts of pregnenolone when high (probably unphysiological) calcium concentrations were present. The present findings suggest that calcium is required at the mitochondrial level for ACTH-induced effects on pregnenolone synthesis, and the reported ACTH-induced increase in intraadrenal calcium may thus amplify the effects of ACTH on steroidogenesis. However, it seems unlikely that calcium is the agent primarily responsible for mediating the ACTH-induced steroidogenic effect at the mitochondrial level.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0013-7227
pubmed:author
pubmed:issnType
Print
pubmed:volume
103
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1264-71
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1978
pubmed:articleTitle
On the role of calcium in adrenocorticotropin-induced changes in mitochondrial pregnenolone synthesis.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S.