[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).

CONCLUSION

These findings indicate that retinoic acid does not have a general effect on apolipoprotein secretion in HepG2 cells.