Changes in lipid synthesis in rat adipose tissue during development.

Lipogenesis in rat adipose tissue during postnatal development has been studied by measuring the incorporation of labeled glucose into lipid in fat cells and the activities of certain enzymes which participate in lipogenesis. It was found that: (1) Fatty acid synthesis from glucose is negligible in the suckling period. After weaning, it increases rapidly and reaches a plateau at the age of 10 weeks. (2) Insulin sensitivity is negligible in the suckling period. After weaning it rises and then declines. (3) Activities of ATP citrate lyase and acetyl CoA carboxylase are maintained at a low level in the suckling period. After weaning, these activities rise rapidly and then decline. (4) Weaning rats onto a high-fat diet showed decreases in glucose incorporation into fatty acids, insulin sensitivity, ATP citrate lyase activity and acetyl CoA carboxylase activity.