Lipoprotein lipase activity in F1 heart cell cultures. Effect of dialyzable serum factors on enzyme stability and enzyme synthesis.
F1 heat cell cultures were grown in F-10 medium containing 20% fetal calf and horse serum and after 6-7 days showed high activity of lipoprotein lipase. When the culture medium contained 20% serum which had been dialyzed against F-10 medium, a 75% decline in lipoprotein lipase activity occurred after 3 h of incubation. Cultures incubated with 20% dialyzed serum and dialysate, obtained after 24 h dialysis of serum against F-10 medium, retained full enzyme activity. Restoration of enzyme activity, lost upon incubation with dialyzed serum, became apparent only 2 h after incubation of the cells with dialysate and dialyzed serum and was complete after 24 h. The effectiveness of the dialysate was not affected by trichloroacetic acid precipitation, ether extraction, exposure to pronase or to 80 degrees C for 10 min; it was retained after chromatography of DEAE cellulose but was lost after elution from CM cellulose colums. Addition of spermidine and spermine to culture media containing dialyzed serum did prevent partially the decline in lipoprotein lipase activity of the heart cell cultures. These polyamines were also able to stabilize lipoprotein lipase activity of heart homogenates incubated at 37 degrees C. However, these compounds were not effective in resoration of enzyme activity of cultured cells lost after exposure to dialyzed serum. It appears that positively charged low molecular weight molecules present in sera of various species are required for the stabilization and synthesis of lipoprotein lipase in heart cell cultures.
D000818:Animals; D001790:Blood Physiological Phenomena; D002478:Cells, Cultured; D003956:Dialysis; D005260:Female; D008071:Lipoprotein Lipase / Q000096:biosynthesis / Q000378:metabolism*; D008297:Male; D009206:Myocardium / Q000201:enzymology*; D011073:Polyamines / Q000494:pharmacology; D051381:Rats
D011073:Polyamines; D008071:Lipoprotein Lipase