[Effects of retinoic acid on secretion of apolipoproteins A I, A II, B100, C III and E by cultured HepG2 cells].
OBJECTIVE
This study inquired into the role of retinoic acid in lipoprotein metabolism.


METHODS
We observed the effect of retinoic acid on the secretion of apolipoproteins A I, A II, C III, B100 and E by cultured HepG2 cells. The apolipoprotiens contents in culture media were measured by radioimmunodiffusion assay (RID) kits developed by our research laboratory. 20-fold lyophilizely condensed culture media were used for the assays.


RESULTS
Retinoic acid increased the secretion of apoA I, B100, C III and A II, and it inhibited the secretion of apoE. The effect of retinoic acid was strengthened in a dose-dependent manner. When the concentration of retinoic acid in cultured media was 2 x 10(-4) mol/l, the secretion of apoA I, A II, B100 and C III increased by 14.3% (P < 0.01), 23.8% (P < 0.05), 16.1% (P < 0.01) and 47.6% (P < 0.01) respectively, and the secretion of apoE decreased by 37.2% (P < 0.01).


CONCLUSIONS
These findings indicate that retinoic acid does not have a general effect on apolipoprotein secretion in HepG2 cells.
Apolipoprotein Research Unit, School of Basic Medical Sciences, WCUMS, Chengdu 610044, China.
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D016632:Apolipoprotein A-I / Q000378:metabolism; D016633:Apolipoprotein A-II / Q000378:metabolism; D001053:Apolipoproteins / Q000378:metabolism*; D001055:Apolipoproteins B / Q000378:metabolism; D001056:Apolipoproteins C / Q000378:metabolism; D001057:Apolipoproteins E / Q000378:metabolism; D018197:Hepatoblastoma / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology / Q000503:physiopathology*; D014212:Tretinoin / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D016632:Apolipoprotein A-I; D016633:Apolipoprotein A-II; D001053:Apolipoproteins; D001055:Apolipoproteins B; D001056:Apolipoproteins C; D001057:Apolipoproteins E; D014212:Tretinoin