Effect of food intake at various ages (fetal, suckling and weaning periods) on adipose tissue cellularity was studied.
1) Rats were given a restricted diet on weaning and later allowed free access to diet. Fat pads of these animals recovered normal weight on refeeding and no differences in cell number or cell size were observed.
2) Food intake was varied by changing the litter size during the suckling period and, after weaning, animals were given free access to diet. Fat pads of rats raised in small litters were heavier than those of rats raised in large litters. The differences in adipose tissue weight were accounted for by differences in cell size and cell number.
3) Maternal rats were given a restricted diet during pregnancy. The pups were irregular in their weight. Pups of the restricted group which were smaller than pups of the control group at birth were chosen and raised normally. Fat pads of these animals were lighter than those of control animals and could be explained in terms of differences in cell size. From these findings, it was suggested that cellular effects of early feeding depended on the phase of growth in the rat.