We increased the mass of interscapular brown adipose tissue in rats by dietary manipulation (“cafeteria” feeding), cold exposure, or by both. The animals were then used to determine the temperature response of the interscapular brown adipose tissue to dopamine or norepinephrine. These results, and the increase in blood glycerol values, were very similar for either catecholamine. These findings suggest that dopamine may have a role in releasing energy from brown adipose tissue similar to that of norepinephrine in the newborn infant.