"Physiological" and cytotoxic cell death in protein deficiency. A study in developing cerebellum in rats.

Effects of undernutrition on natural ("physiological") and cytotoxic cell death due to X-irradiation was studied in developing cerebellum in rats. Undernutrition was induced right from birth by doubling the litter size. Animals reared in a litter of 8 served as controls. In order to get an idea of the relationship of cell death to phases of the cell cycle, the number of labelled dead cells, in the EGL of the fissure prima, was estimated, at time intervals following administration of 3HTdR in a group of 9-day-old rats. No differences were observed in the quantum of "physiological" cell death as well as in the rate of nuclear autolysis in the two groups. Undernutrition, however, prolonged the G2-M junction in animals X-irradiated with 200 rads. The kinetics of appearance of labelled dead cells suggested that irrespective of the diet the cells die immediately following mitosis, although the "decision to die" was taken at the end of S-phase. It is concluded that the reduction in cell number in the brain in undernutrition is not due to increased cell death.