Document Detail


In micronodular cirrhosis, hepatocytes retain a normal C-25 hydroxylation capacity toward vitamin D3: a study using the rat carbon tetrachloride-induced cirrhotic model.
MedLine Citation:
PMID:  1847894     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
To test further the competence of the cirrhotic liver to metabolize vitamin D3 at C-25, hepatocytes were isolated from controls and from CCl4-induced cirrhotic rat livers, as well as from partially hepatectomized rats. The transformation of D3 into 25-hydroxyvitamin D3 was studied in the presence of 10(7) hepatocytes at D3 concentrations of 20 nmol/L to 15.4 mumol/L. Histologically, micronodular cirrhosis was present in all CCl4-treated rats, whereas controls had normal livers; portal venous pressure (p less than 0.008) and intrahepatic collagen content (p less than 0.0001) were significantly increased in CCl4-treated rats, whereas no difference was found between the two groups in the total and ionized serum calcium, D3 metabolites, ALT, AST and alkaline phosphatase. Cytochrome P-450 was 0.27 +/- 0.02 and 0.25 +/- 0.02 nmol/10(6) hepatocytes in controls and cirrhotic rats (N.S.), and it significantly increased in both groups after phenobarbital or 3-methylcholanthrene administration (p less than 0.0001). 25-Hydroxyvitamin D3 formation was best described by power law equations and varied between 0.02 +/- 0.0004 and 29.57 +/- 2.8 in controls, and 0.024 +/- 0.0004 and 32.0 +/- 7.0 pmol.hr-1.10(6) hepatocytes-1 in cirrhotic rats. No statistically significant difference was found in the slopes of the 25-hydroxyvitamin D3 formation, but the y-axis intercept was found to be lower in cirrhotic rats under basal resting conditions (p less than 0.005). Inducers of the mixed function oxidases significantly increased 25-hydroxyvitamin D3 formation in controls as well as in cirrhotic rats (p less than 0.005). Moreover, both groups were found to respond similarly to the addition of modulators of the enzyme such as the calcium ionophore A23187 and parathyroid hormone. Partial hepatectomy was also without effect on the activation of D3. Furthermore, the cell sequestration of D3 was also found to be unperturbed in hepatocytes obtained from either cirrhotic or partially hepatectomized livers. The data indicate that in well-compensated micronodular cirrhosis, the C-25 hydroxylation of D3 is generally intrinsically normal at the cellular level and that it also remains fully responsive to in vivo and in vitro modulators of its activity.
Authors:
C Dubé; S Vallières; C Ethier; N Benbrahim; C Tremblay; M Gascon-Barré
Related Documents :
15163064 - Influence of serum from rats with fulminant hepatic failure on hepatocytes in a bioarti...
7461424 - Ultrastructural cytochemical investigations on adenyl cyclase activity in isoprenaline-...
7462214 - Manganese effects on gluconeogenesis.
10597904 - The effect of inducing agents on the metabolism of ethidium bromide by isolated rat hep...
6417034 - Variations of plasma lipid fractions in relation to age in two models of obesity.
698124 - The control of hepatic iron uptake: correlation with transferring synthesis.
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Hepatology (Baltimore, Md.)     Volume:  13     ISSN:  0270-9139     ISO Abbreviation:  Hepatology     Publication Date:  1991 Mar 
Date Detail:
Created Date:  1991-04-09     Completed Date:  1991-04-09     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8302946     Medline TA:  Hepatology     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  489-99     Citation Subset:  IM    
Affiliation:
André-Viallet Clinical Research Center, St. Luc Hospital, Montreal, Quebec, Canada.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Animals
Calcifediol / metabolism
Carbon Tetrachloride
Cholecalciferol / metabolism*
Cytochrome P-450 Enzyme System / metabolism
Hydroxylation
Liver / cytology,  drug effects,  metabolism*
Liver Cirrhosis, Experimental / chemically induced,  metabolism*,  pathology
Male
Methylcholanthrene / pharmacology
Phenobarbital / pharmacology
Rats
Rats, Inbred Strains
Chemical
Reg. No./Substance:
19356-17-3/Calcifediol; 50-06-6/Phenobarbital; 56-23-5/Carbon Tetrachloride; 56-49-5/Methylcholanthrene; 67-97-0/Cholecalciferol; 9035-51-2/Cytochrome P-450 Enzyme System

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


Previous Document:  Usefulness of pulsed Doppler ultrasound in detection of angiographically evident recurrence of hepat...
Next Document:  Proton accumulation and ATPase activity in Golgi apparatus-enriched vesicles from rat liver.