| Stimulation of cholesterol side-chain cleavage enzyme activity by cAMP and hCG in MA-10 Leydig tumor cells. | |
| | |
MedLine Citation:
|
PMID: 2855024 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
Using a cloned Leydig tumor cell line (designated MA-10), we have studied the activity of cholesterol side-chain (CSCC) enzyme, the rate-determining step in steroidogenesis, in mitochondria isolated from cells pretreated either with human chorionic gonadotropin (hCG) or dibutyryl cyclic adenosine monophosphate (dbcAMP). Results showed a slight but significant increase in CSCC activity with treatment by cAMP (25% increase) and hCG (60% increase), as compared to mitochondria isolated from nontreated control cells. However, this stimulation of CSCC activity appears to be of limited significance when compared to the approximately 1000-fold or greater increase observed in progesterone production in the presence of hCG or dbcAMP. On the other hand, unstimulated MA-10 cells or isolated mitochondria efficiently converted 25-hydroxycholesterol and 22R-hydroxycholesterol into progesterone, and this conversion was not affected by cycloheximide. The addition of cholesterol to intact cells or to isolated mitochondria did not affect progesterone production. Our observations clearly indicate that given the proper hydroxy substrates (22R-hydroxycholesterol or 25-hydroxycholesterol), MA-10 Leydig cells are able to convert them into progesterone without any stimulation by steroidogenic stimuli, i.e. cAMP or hCG. Since MA-10 Leydig cells can efficiently convert 22R-hydroxycholesterol--an intermediate in CSCC reaction--into progesterone, these results suggest that the key regulatory step in the mechanism of trophic hormone-stimulated steroid production is the first hydroxylation step of the 3 sequential monooxygenation reactions involved in the conversion of cholesterol to pregnenolone. |
| | |
Authors:
|
L R Chaudhary; D M Stocco |
Related Documents
:
|
8579844 - Kit ligand mediates survival of type a spermatogonia and dividing spermatocytes in post... 10689204 - Histochemical tracing of bismuth in testis from rats exposed intraperitoneally to bismu... 2907804 - Role of mammalian y chromosome in sex determination. 1807554 - Ultrastructural demonstration of mercury in sertoli and leydig cells of the rat followi... 9493964 - Glycol ethers induce death and necrosis in human leukemia cells. 22797064 - The histone methyltransferase mmset/whsc1 activates twist1 to promote an epithelial-mes... |
Publication Detail:
|
Type: Journal Article; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
|
Title: Biochimie Volume: 70 ISSN: 0300-9084 ISO Abbreviation: Biochimie Publication Date: 1988 Dec |
Date Detail:
|
Created Date: 1989-07-14 Completed Date: 1989-07-14 Revised Date: 2007-11-14 |
Medline Journal Info:
|
Nlm Unique ID: 1264604 Medline TA: Biochimie Country: FRANCE |
Other Details:
|
Languages: eng Pagination: 1799-806 Citation Subset: IM |
Affiliation:
|
Department of Biochemistry, Texas Tech University Health Sciences Center, Lubbock 79430. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Allosteric Regulation Animals Cholesterol Side-Chain Cleavage Enzyme / metabolism* Chorionic Gonadotropin / pharmacology* Cyclic AMP / pharmacology* Cycloheximide / pharmacology Enzyme Induction Hydroxycholesterols / metabolism Leydig Cell Tumor / enzymology, metabolism Mitochondria / enzymology Progesterone / biosynthesis Substrate Specificity Tumor Cells, Cultured |
| Grant Support | |
ID/Acronym/Agency:
|
HD 00685/HD/NICHD NIH HHS; HD 17481/HD/NICHD NIH HHS |
| Chemical | |
Reg. No./Substance:
|
0/Chorionic Gonadotropin; 0/Hydroxycholesterols; 57-83-0/Progesterone; 60-92-4/Cyclic AMP; 66-81-9/Cycloheximide; EC 1.14.15.6/Cholesterol Side-Chain Cleavage Enzyme |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Differences between normal and transformed murine fibroblasts in the expression of various promoter/...
Next Document: Characterization and complete amino acid sequence of ferredoxin II from Desulfovibrio vulgaris Miyaz...