1. Liver biopsies were performed through laparotomy wounds in six baby baboons during the development of a kwashiorkor-like illness induced by low-protein, high-carbohydrate diets similar to those consumed by many East African children. Up to six biopsies have been performed successfully in one animal within a period of 1 year. This material has been studied by light and electron microscopy.
2. A similar study was carried out in two healthy animals fed on an adequate diet. A description is given of liver ultrastructure in normal baby baboons, based on examination of these biopsies.
3. The hepatocytes of the malnourished animals contained excessive amounts of glycogen and showed a reduction in rough and smooth endoplasmic reticulum. Even at the height of an illness indistinguishable clinically from marasmic kwashiorkor, there was no excess of liver fat except in those animals whose diet contained sucrose. This may have been the result of stimulation of hepatic triglyceride synthesis by fructose.
4. In no specimen from the experimental group were there signs of serious progressive and irreversible liver cell damage which might have been expected if liver dysfunction were an important component of kwashiorkor.
5. Biopsies performed in one malnourished animal during recovery showed a return of liver ultrastructure to normal.