title: Distribution of 2,4,5,2',4',5'-hexachlorobiphenyl among lipoproteins during pregnancy and lactation in the rat.
abstract: 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.
mesh_terms: D000818:Animals; D005260:Female; D007774:Lactation; D008074:Lipoproteins / Q000097:blood*; D008075:Lipoproteins, HDL / Q000097:blood; D008077:Lipoproteins, LDL / Q000097:blood; D008079:Lipoproteins, VLDL / Q000097:blood; D011078:Polychlorinated Biphenyls / Q000097:blood*; D011247:Pregnancy; D011270:Pregnancy, Animal; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors; D014280:Triglycerides / Q000097:blood
chemical_list: D008074:Lipoproteins; D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL; D008079:Lipoproteins, VLDL; D014280:Triglycerides; C030106:very low density lipoprotein triglyceride; D011078:Polychlorinated Biphenyls; C014024:2,4,5,2',4',5'-hexachlorobiphenyl