Fig. 3.

(A) Interscapular BAT. UCP1 immunostaining of a C57BL/6J mouse maintained at 6°C for 10 days shows three different cell types: UCP1-negative unilocular adipocytes (*), UCP1-negative multilocular adipocytes (black arrows), and UCP1-positive multilocular adipocytes (white arrowheads). Scale bar: 10 µm. (B) Total number of adipocytes contained in the adipose organ of C57BL/6J mice maintained at 28°C or 6°C for 10 days. The overall number of adipocytes in the organ was not significantly changed in either experimental condition (P = 0.14). In the cold-acclimated group, the total number of UCP1-positive multilocular adipocytes increased significantly (P = 0.01). Unilocular adipocytes decreased significantly by the same amount (P = 0.05). UCP1-negative multilocular adipocytes were almost unchanged. Data are shown as mean ± SEM.