THE EFFECT OF EXPERIMENTAL HEMORRHAGIC SHOCK ON SERUM HDL-LEVEL IN RABBITS

In order to study the changes in the levels of serum HDL (high density lipoprotein) by hypovolemic shock due to hemorrhage, blood was withdrawn from five female rabbits through a catheter inserted into an aortic arch via carotid artery. Three to five milliliters of blood intermittently withdrawn, which accerelated the hemorrhagic shock condition, were served for the lipid and lipoprotein analysis. During the experimental period, the portal blood flow and mean blood pressure of aortic arch were measured and Indocyamine green test (Rl5) performed frequently in the animals.
(1) The serum concentration of HDL-cholesterol and HDL-phospholipids (d.>1.063 which involves VHDL (very high density lipoprotein)-phospholipids) gradually decreased and the total and LDL (low density lipoprotein) + VLDL (very low density lipoprotein)-cholesterol and phospholipids showed slight decreases immediately after the commencement of experiment and kept almost constant thereafter.
(2) The magnitude of decrease in lipids was higher in HDL2 than HDL3 fraction, and VHDL-phospholipids were not affected by hemorrhagic shock.
(3) The lipid and protein compositcon of HDL2 revealed a significant decrease in percent cholesterol and phospholipids accompanied by a relative increase in percent protein and triglycerides, and that of HDL3 showed no change in the serum 270 minutes after shock.
(4) Substantially high elevation of catecholamines, temporal increase in free fatty acid and slight increase in serum triglycerides were observed during the experimental period.
The hemorrhagic shock seems to disturb the regulation of serum HDL levels and its constituents.