Lipogenesis in the brown adipose tissue of the fetal baboon

The ultrastructural and lipogenic capacity of the white and brown adipose tissue (WAT and BAT) of 10 baboon fetuses (gestational age, 138-183 days) were studied. The axillary, interscapular and pericardiac sites had at least 50% brown fat cells while the retroorbital site contained white adipocytes only. Both WAT and BAT incorporated 3H2O and 14C-glycerol into lipids at similar high rates. The activities of enzyme acetyl CoA carboxylase and glycerokinase were higher than those reported in human BAT and comparable to these reported in rodent BAT under unstimulated conditions. It is concluded that in the fetal baboon adipose tissue is capable of considerable de novo lipogenesis and that, despite the differences in microscopic appearance, WAT and BAT have similar lipogenic potentials with respect to the parameters measured.