1990 Volume 36 Issue 3 Pages 251-263
In our previous report, we have described morphological changes in hepatocytes, e.g., enlargement of mitochondria and a change in the lamellar formation of rough endoplasmic reticulum, produced by short-term feeding of a protein-free diet to rats. In order to examine whether or not these morphological changes in the subcellular organella are accompanied by any functional and compositional changes, we mea-sured the P/O ratio and respiratory rate of mitochondria, and the phos-pholipid fatty acids of the mitochondrial and microsomal membranes in the liver of rats fed a protein-free diet for a short period. Feeding rats the protein-free diet for 4 days or 27-28 days had no effect on the rate of hepatic mitochondrial oxygen consumption (State 3 respiration). The diet significantly decreased the P/O ratio on the 4th day, but did not affect it on the 27-28th days. The decreased P/O ratio observed on the 4th day returned to the control level after overnight refeeding of a 20% casein diet. Main compositional changes induced by feeding rats the protein-free diet for 2 days were significant decreases in the phospholipid/protein ratios of the total liver and mitochondrial inner membrane, a tendency of an increase in the ratio of phosphatidylcholine (PC) to total phospholipids in the mitochondrial outer membrane, a significant decrease and a tendency of decrease in the arachidonate/linoleate ratio in the phosphatidyletha-nolamine (PE) and PC, respectively, in the mitochondrial outer mem-brane. Some of these results were discussed in relation to the morpho-logical changes in mitochondria and rough endoplasmic reticulum pro-duced by short-term feeding of the protein-free diet which we previ-ously reported.
