Influence of Pregnancy and Cortisone Treatment on Brown Adipose Tissue in Bats. ∗

Summary

The interscapular brown adipose tissue of the bat (Tadarida b. mexicana) undergoes significant fluctuations in lipid content during the reproductive cycle. There is a progressive accumulation of lipid in the brown fat cells, beginning in early pregnancy and reaching a maximum level late in the gestation period. In contrast, during and shortly after parturition the brown adipose tissue is essentially deplete of lipid, while 2 weeks following delivery lipid can again be found in the brown fat cells. Cortisone treatment of non-gravid bats results in increased lipid accumulation in the brown fat similar to that observed in the pregnant animal. A gradual increase in weight of brown fat parallels lipid hypertrophy. The role of adrenal activity in directing alterations in the lipid content of the interscapular brown adipose tissue of bats during the reproductive cycle is discussed.