cytotoxic effect of chelidonium alkaloids on cells isolated from adult rat liver

Alkaloids of the aerial parts of chelidonium were extracted in the salt form, and their aqueous solutions were prepared in different concentrations. Rat hepatocytes were obtained by liver perfusion. The alkaloidal solutions were added to suspensions of hepatocytes in petri dishes and the mixtures were incubated. Two types of controls have been used; in one type, no alkaloidal extract was added to the media, and in the other, alkaloidal extract of datura which has no cytotoxic activity was added to the hepatocytes. Intracellular LDH activity as well as the activity of leaked LDH into the media, the glucose uptake by the cells, and the glycogen contents of the cells were determined after incubation. The results indicate that 0.05 ml of the alkaloidal solution of chelidonium has no detectable effect on LDH activity during a 240 minute incubation period. With 0.1 ml doses, detectable changes were observed only after 240 minutes of incubation. When 0.2 ml doses were used, the intracellular LDH activity was lowered by 3.23,6.79 and 30.89% after 60,120 and 240 minutes of incubation respectively, as compared with the controls. The activity of leaked LDH into the media was, on the other hand, increased as the duration of incubation was increased. Determination of glucose in different media showed that the uptake of this sugar by the hepatocytes incubated with chelidonium decreased as the dose and incubation periods increased. On the other hand, as the glycogen content of the hepatocytes incubated with chelidonium was the same as that of the controls, we believe that the hepatocytes lost their viability in the presence of chelidonium-derived cytotoxic alkaloids

Diurnal variations in hepatic and plasma lipids and in the activities of hepatic phosphatidate phosphohydrolase and heart lipoprotein lipase

Diurnal variations of liver and plasma lipids and of the activities of liver phosphatidate phosphohydrolase and heart lipoprotein lipase were determined in male rats kept for 15 days with alternating 12 h periods of darkness and light. Plasma triacylglycerol concentration increased during the dark period reaching a peak at 07:00 h. Hepatic phosphatidate phosphohydrolase activity was also elevated at the early part of the dark with a peak at 23:00 h. The circadian rhythms of hepatic triacylglycerol and phospholipids were less pronounced. Heart lipoprotein lipase activity was maximum at 15:00 h and its nadir point was at 07:00 h. The data were used to calculate definite circadian rhythm for VLDL-triacylglycerol secretion rate which coincided with those of liver phosphatidate phosphohydrolase and plasma triacylglycerol. It is concluded that the change in hepatic phosphatidate phosphohydrolase activity could be responsible for the diurnal variations of VLDL-triacylglycerol secretion rate and that both lipoprotein lipase activity and VLDL secretion rate are the major causes of plasma triacylglycerol diurnal variations