TY - JOUR T1 - Distribution of 2,4,5,2',4',5'-hexachlorobiphenyl among lipoproteins during pregnancy and lactation in the rat. JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 263 LP - 268 VL - 230 IS - 2 AU - M Spindler-Vomachka AU - M J Vodicnik Y1 - 1984/08/01 UR - http://jpet.aspetjournals.org/content/230/2/263.abstract N2 - The mechanism by which polychlorinated biphenyls are transferred from adipose tissue to the mammary gland during late pregnancy and lactation is unknown. Lipoproteins were investigated as a possible vehicle of transport. 2,4,5,2',4',5'-[14C] Hexachlorobiphenyl (6-CB) distribution among very low-, low- and high-density lipoproteins and the protein-rich bottom fraction was examined in virgin controls, in pregnant animals on days 9 and 18 of gestation, in mothers on day 10 of lactation and in suckling pups. Plasma obtained 1 hr after an i.v. injection of 6-CB was separated into the various lipoprotein fractions and their lipid composition analyzed. With advancing pregnancy, there was a shift in 6-CB distribution from the higher to lower density lipoproteins. A linear increase was observed in the amount of very low-density lipoprotein as well as the proportion of plasma 6-CB associated with it. Corresponding decreases occurred in the proportion of 6-CB associated with low-density lipoprotein and the bottom fraction. During late pregnancy, very low-density lipoprotein became the primary carrier of 6-CB in vivo. The pattern of 6-CB distribution among lipoproteins on day 10 of lactation resembled that on day 9 of pregnancy. Suckling pups exhibited the highest proportion of plasma 6-CB in low- and high-density lipoprotein. The shifts in the distribution of 6-CB during pregnancy and lactation were related to changes in the lipid constituents of plasma and the individual lipoproteins. ER -