LIPID-METABOLISM AND STRUCTURAL AND FUNCTIONAL-CHARACTERISTICS OF MEMBRANES OF THE ENDOPLASMIC-RETICULUM IN THE REGENERATING RAT-LIVER

The relationship of the metabolism of neutral lipids and phospholipids to the structural and functional characteristics of membranes of the endoplasmic reticulum in the regenerating rat liver (13 h after the operation, i.e., the G-period of the cell cycle) was investigated An increase in the degree of development of membranes of the endoplasmic reticulum and an increase in the content of nonesterified fatty acids (NEFA) and triglycerides (TG) in microsomes of the regenerating rat liver was demonstrated. The relative specific radioactivity of fractions of neutral lipids and phospholipids in microsomes of the regenerating rat liver was lower than in the control animals, which was due to the high rate of microsomal lipid metabolism in the regenerating liver with other cell organelles. The changes in the lipid content and rate of lipid metabolism in the regenerating liver were accompanied by an increase in the micro-viscosity of these membranes and a decrease in the activity of the membrane-bound enzyme glucose-6-phosphatase. Different time-dependent changes in lipid synthesis and metabolism were detected for the NEFA and PG fractions, which may be considered as an endogenous factor determining the structuro-functional properties of the membranes in the endoplasmic reticulum.