Aim To study the effects of glucagon, dibutyryl cAMP on secretion of apolipoproteins A_Ⅰ,A_Ⅱ,CⅢ,B100 and E by HepG2 cells. Methods The apolipoprotiens contents in culture media were measured by radioimmuodiffusion assay (RID) kits developed by authors' research laboratory. 20-fold lyophilizely condensed culture media were used for the assays. Results When the concentration of glucagon is 4×10 -7 mol/L in culture media, the secretion of apoA_Ⅰ,A_Ⅱ,B100 and E decreased 47.7%, 54.1%, 32.7% and 33.2%(P<0.01) respectively, while the secreation of apoCⅢ increased 89.1%(P<0.01); When the concentration of dibutyryl cAMP is 1×10 -3 mol/L in culture media, the secretion of apoA_Ⅰ,B100 and E decreased 12.3%, 24.9% and 16.1% (P<0.01)respectively, while the secretion of apoA_Ⅱ and CⅢ increased 66.1% and 142.6%(P<0.01). Conclusion [WT5”BZ]Glucagon and dbcAMP had similar effects on the secretion of apolipoproteins by cultured HepG2 cells.