Body fat in pregnant rats at mid- and late-gestation.

Carcass fat content was estimated in fed 12- and 19-day pregnant rats and fed and 48 hour starved virgin females following both specific gravity determination and direct gravimetry of extracted lipids. No change in body fat accumulation was found in 12-day pregnant rats whereas in 19-day pregnant animals it increased significantly. A significant correlation was also found when the percentage of carcass fat was plotted against specific gravity considering values from all subjects. Results indicate that in spite of reported maternal anabolic changes in the rat at midgestation fat accumulation occurs later in pregnancy when the mother has the highest food intake, which makes available sufficient substrates to support both fetal growth and body lipidic deposition.