Abstract
Newborn rats were redistributed among stock diet-fed mothers to obtain litter sizes of 12. Each mother was then placed on one of three diets. Diet A contained 10% protein (group 1), diet B, 3% protein (group 2), diet C was identical to A but mothers were restricted to one-half the daily ration (group 3). After weaning, all pups had free access to the stock diet. At 8 weeks, epididymal fat pads of group 1 animals were heavier than those in groups 2 and 3, and the difference was accounted for by differences in cell number and/or cell size. The difference between groups 1 and 3 was due solely to cell size. By 12 weeks no difference was observed between groups 1 and 3. However, differences were still present when groups 1 and 2 were compared. The rates of in vitro glycerol release and epinephrine stimulation were comparable in all groups if expressed on a per cell basis; therefore, total release was diminished in the smaller animals with fewer cells. Per cell metabolic differences appeared to be related to age and marked differences in cell size rather than prior treatment. Thus maternal caloric restriction alone produced transient effects on adipose tissue metabolism and cellularity while maternal protein restriction resulted in permanent changes.