In vivo changes in the rates of total lipid and fatty acid synthesis in liver and white adipose tissues of male rats during postweaning growth.

1. In suckling rats, lipid synthesis is low in liver and adipose tissues. The rest of carcass is the major site of body lipogenesis. 2. After weaning, lipid synthesis (per g of wet wt) strongly increases in liver, perirenal and subcutaneous adipose tissues, and rest of carcass. The relative contributions of liver and both adipose tissues to body lipogenesis are about 35-40 and 6-9% respectively, but the rest of the carcass is still the main site of lipogenesis up to the age of 50 days. 3. In adult rats, lipid synthesis (per g of wet wt) remains high in liver but is strongly reduced in adipose tissues and carcass. Liver becomes the principal site of body lipogenesis.