Modulation of LDL catabolism by sodium nitroprusside and PGE2 in human peripheral blood lymphocytes

The effect of nitric oxide donor--sodium nitroprusside (NaNP) and PGE2 on the LDL-receptor activity and LDL cellular accumulation by isolated human blood lymphocytes was investigated. Preincubation of lymphocytes with lipoprotein deficient medium (LPDS) resulted in the increase of the LDL-receptor activity and the LDL-cellular accumulation. NaNP (30-300 microM) dose-dependently prevented the increase of the LDL-receptor activity as well as the accumulation of LDL by lymphocytes. However, in "starwing" cells (cells with high LDL-receptor activity) the effect of NaNP on the receptor activity was biphasic. At concentration up to 100 microM NaNP inhibited, while at a concentration of 300 microM, it activated the LDL-receptor activity. PGE2 (3-30 microM) inhibited LDL catabolism, however, this effect was hardly concentration-dependent.