Document Detail

The effect of dibutyryladenosine 3',5'-monophosphate on the synthesis of bile salts in isolated hepatocytes from rat.
MedLine Citation:
PMID:  6313363     Owner:  NLM     Status:  MEDLINE    
The effect of dibutyryladenosine 3',5'-monophosphate (Bt2cAMP) on the synthesis of conjugated cholic, chenodeoxycholic and beta-muricholic acids has been investigated. Hepatocytes were incubated with 1 mM Bt2cAMP for 3 h at 37 degrees C. In cells from rats with a basal rate of bile salt synthesis (soft-diet-fed rats) production of conjugated cholic acid was increased about two fold, synthesis of conjugated chenodeoxycholic acid was increased 10-20-fold but formation of its metabolite, conjugated beta-muricholic acid, was decreased by 30-50% in the presence of the cyclic nucleotide. The sum of the amounts of the three bile salts produced (total bile salt synthesis) was increased 30-50% by Bt2cAMP. When hepatocytes were prepared from rats in which bile salt synthesis had been stimulated by feeding the bile salt sequestrant, cholestyramine, Bt2cAMP had no effect on conjugated cholic acid synthesis, increased conjugated chenodeoxycholic acid production 3-5-fold and decreased conjugated beta-muricholic acid synthesis by about 50%. Total bile salt synthesis was unchanged. The ratio of the amount of conjugated cholic acid to conjugated chenodeoxycholic acid + conjugated beta-muricholic acid produced, an indication of the activity of 7 alpha-hydroxycholest-4-en-3-one 12 alpha-hydroxylase, was raised by Bt2cAMP in hepatocytes from soft-diet-fed but not in those from cholestyramine-fed rats. The effects of the cyclic nucleotide on the synthesis of the three bile salts in hepatocytes from soft-diet-fed rats were found to be saturable at a concentration of about 2 mM. Responses were half-maximal at concentrations of Bt2cAMP varying between 0.5 and 1.5 mM. These results suggest that in hepatocytes from rats with a basal rate of bile salt synthesis Bt2cAMP has effects at three different stages in the pathway, at the level of cholesterol 7 alpha-hydroxylase, 7 alpha-hydroxycholest-4-en-3-one 12 alpha-hydroxylase and chenodeoxycholine acid 6 beta-hydroxylase. In cells from rats in which bile salt synthesis has been stimulated only the effect at the chenodeoxycholic acid 6 beta-hydroxylase level is apparent. Bt2cGMP and Bt2cCMP had no effect on the synthesis of any of the bile salts measure, showing that the effects are specific for Bt2cAMP. The ratio of the amounts of the three bile salts found inside the cells to those found in the medium was decreased by about 90% when Bt2cAMP was present in the hepatocyte incubations. This effect was mimicked by Bt2cGMP and to a lesser extent by Bt2cCMP.(ABSTRACT TRUNCATED AT 400 WORDS)
K M Botham; G S Boyd
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  European journal of biochemistry / FEBS     Volume:  136     ISSN:  0014-2956     ISO Abbreviation:  Eur. J. Biochem.     Publication Date:  1983 Nov 
Date Detail:
Created Date:  1983-12-17     Completed Date:  1983-12-17     Revised Date:  2007-07-23    
Medline Journal Info:
Nlm Unique ID:  0107600     Medline TA:  Eur J Biochem     Country:  GERMANY, WEST    
Other Details:
Languages:  eng     Pagination:  313-9     Citation Subset:  IM    
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MeSH Terms
Bile Acids and Salts / biosynthesis*
Bucladesine / pharmacology*
Culture Media / analysis
Liver / metabolism*
Rats, Inbred Strains
Reg. No./Substance:
0/Bile Acids and Salts; 0/Culture Media; 362-74-3/Bucladesine

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