Potential mechanisms for redistribution of polychlorinated biphenyls during pregnancy and lactation

Xenobiotica. 1987 Mar;17(3):299-310. doi: 10.3109/00498258709043940.

Abstract

Female mice treated with 14C-2,4,5,2',4',5'-hexachlorobiphenyl (6-CB) two weeks prior to mating eliminated virtually their entire body burden of the compound through milk during one lactation cycle. 6-CB was shown to distribute among rat and human plasma lipoproteins and protein in vitro. It was readily transferred among plasma constituents and its distribution was related to the triacylglycerol:protein ratio in plasma. At one hour following its intravenous administration to virgin rats, 6-CB was primarily distributed to LDL. With the hypertriglyceridemia of late pregnancy, more than 70% of circulating 6-CB was associated with VLDL. VLDL is a major substrate for mammary gland lipoprotein lipase which is elevated during lactation. When 6-CB was complexed with human VLDL and injected i.v. into late pregnant mice, mammary gland concentrations of 6-CB exceeded those of adipose tissue at all sacrifice times between 5 min and 6 h. No differences between adipose tissue and mammary gland concentrations of 6-CB were observed with Emulphor:ethanol:saline as vehicle until 6 h. Isolated hepatocytes were capable of secreting protein and triacylglycerol in the form of VLDL into serum-free media. Eighty percent of 6-CB released from hepatocytes was in association with VLDL, with the remainder in association with protein. Adipocytes isolated from epididymal fat pads of male rats which were pretreated with 6-CB released progressively less radioactivity to incubation media with time after treatment even though PCB content of these cells increased. 6-CB may not be evenly distributed among adipocyte lipids.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adipose Tissue / metabolism
  • Animals
  • Blood Proteins / metabolism
  • Female
  • Kinetics
  • Lactation / metabolism*
  • Lipoproteins, LDL / blood
  • Lipoproteins, VLDL / blood
  • Liver / metabolism
  • Mammary Glands, Animal / metabolism
  • Polychlorinated Biphenyls / blood
  • Polychlorinated Biphenyls / metabolism*
  • Pregnancy
  • Pregnancy, Animal / metabolism*
  • Rats
  • Rats, Inbred Strains
  • Tissue Distribution
  • Triglycerides / blood

Substances

  • Blood Proteins
  • Lipoproteins, LDL
  • Lipoproteins, VLDL
  • Triglycerides
  • Polychlorinated Biphenyls
  • 2,4,5,2',4',5'-hexachlorobiphenyl