Influence of adipocyte triglyceride on the partition of 2,2′,4,4′,5,5′‐hexabromobiphenyl between 3T3L1 adipocytes and surrounding pseudoblood

Abstract

Removal from adipose tissue is an important first step in ultimate removal of many lipophilic xenobiotics from the body. This study concerned the elucidation of mechanisms by which hexabromobiphenyl (HBB) was deposited in and removed from adi‐pocytes. Adipocytes derived from the 3T3L1 cell line of mouse fibroblasts were used to conduct studies in vitro. Results support the idea that HBB enters the 3T3L1 adipocyte via passive diffusion. A plot of the velocity of uptake versus concentration was linear, the uptake of HBB does not appear to be energy dependent, and structurally similar biphenyls did not cause an inhibition of uptake. A linear relationship between the quantities of triglyceride and HBB in the cells was found during both uptake of HBB in lipogenesis and removal of HBB in lipolysis (r > 0.98). This supports the contention that the quantity of triglyceride in the cells has a strong influence on the movement of HBB between adipocytes and surrounding pseudoblood. Evidence has been presented that is consistent with the hypothesis that HBB moves freely across the adipocyte membrane and is sequestered in either cells or medium according to its relative solubility in these compartments. Methods to increase the removal of HBB from adipocytes have been proposed.