[Lipid metabolism and structure-activity features of the endoplasmic reticulum membrane in regenerating rat liver].

The relationship between the neutral lipid and phospholipid metabolism and some structure-function peculiarities of regenerating rat liver endoplasmic reticulum membranes (13 hours after surgery, i.e., corresponding to the G1-period of the cell cycle) was studied. There was an increase in the degree of the endoplasmic reticulum membrane development and the nonesterified fatty acid (NFA) and triglyceride (TG) content in regenerating rat liver microsomes. The relative specific radioactivity of neutral lipid and phospholipid fractions in regenerating rat liver microsomes was lower than in control animals, presumably due to the high rate of the microsomal lipid exchange in the regenerating liver with other cell organelles. The changes in the lipid content and rate of their metabolism in the regenerating rat liver were associated with the increase in the membrane microviscosity and the decrease in the activity of the membrane-bound enzyme (glucose-6-phosphatase). The differences in the time-dependent changes in the synthesis and metabolism of lipids in the NFA and TG fractions may be regarded as an endogenous factor determining the structure-function peculiarities of endoplasmic reticulum membranes.