Rates of utilization of intravenous oleylanilide administered chronically to the rat

The constant injection of [14C]oleylanilide into the vena cava of Wistar rats for 7 days with osmotic minipumps was used to estimate tissue distribution of chronically administered anilides. The largest concentrations of the anilide were found in the brown adipose tissue; all other tissues showed much lower proportions. When anilide distribution was expressed as nmol/g lipid, the high concentration of the compound in the brown adipose tissue contrasted with its very low presence in the white adipose tissue; all other tissues showed intermediate concentrations. Anilide-treated rats consumed more food and lost more weight than did controls; their energy balance showed higher energy inefficiency. The results suggest a possible effect of anilides on the thermogenic pathway of the rat brown adipose tissue. In addition, there was a large individual variability in the proportions of anilide present in all tissues, from as little as 0.3% of the total anilide injected in some animals to 6% in others.