RASOULI M, LEHNER R. HEPATOMA McARDLE-RH7777 CELLS HAVE THE SAME RESPONSE AS NORMAL RAT HEPATOCYTES TO BOTH DIBUTYRYL-cAMP AND ANTICALMODULINW-7. Med J Islam Repub Iran 2002; 15 (4) :209-217
URL:
http://mjiri.iums.ac.ir/article-1-785-en.html
From the Department of Biochemistry and Lipid & Lipoprotein Research Group, University of Alberta, Edmonton, Canada T6H 2S2. , mehdi.rasouli@planetaccess.com
Abstract: (4544 Views)
The effects of cAMP-analogue dibutyryl-cAMP and anticalmodulin W-7 were
studied on de novo synthesis and secretion of lipids in cultures of hepatoma McArdle
RH7777 cells and normal rat hepatocytes. Dibutyryl-cAMP and W -7 separately
caused a significant decrease in the secretion of de novo synthesized triacyl
[3H]glycerol in both cultures of McArdle cells and rat hepatocytes. The inhibitory
effects of dibutyryl-cAMP and W-7 were concentration-dependent and appeared
at the lowest concentration examined, 5JlM and 20JlM respectively. DibutyrylcAMP
at a concentration of 50 JlM and W -7 (20 µM) suppressed the secretion of
triacylglycerol by approx. 38% (p<0.05) and 37% (p<0.05) respectively. Dibutyryl.cAMP
but not W -7 also suppressed the secretion of phosphatidylcholine significantly.
Dibutyryl-cAMP and W-7 had no significant effect upon [3H]glycerollabeled
de novo formed triacylglycerol and phosphatidylcholine, except at the
highest concentration tested, 500JlM and 50JlM respectively, where both
triacylglycerol and phosphatidylcholine synthesis were suppressed significantly.
Similar findings were obtained on cultured hepatocytes.
The molar ratios of newly made triacylglycerol/phosphatidyl choline in the
media and cells of hepatocytes were about four times compared to that of McArdle
cells, indicating more lipidation and core expansion of nascent lipoprotein particles
in hepatocytes. The molar ratio of triacylglycerol/phosphatidyl choline in
the medium and cells of cultured McArdle cells was unchanged significantly i n
the presence of either dibutyryl-cAMP or W-7. However, the molar ratio was
decreased 25% (p