TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) causes reduction in the low density lipoprotein (LDL) receptor activities in the hepatic plasma membrane of the guinea pig and rat.

Administration of 1 micrograms/kg (single intraperitoneal injection and studied after 10 days) of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to young male guinea pigs was found to cause a significant reduction in binding of low-density lipoprotein (LDL) to its receptor on the hepatic plasma membrane. This reduction in LDL binding is not caused by the decrease of food intake by treated animals since pair-fed control animals had significantly higher LDL binding than treated animals. It was also found that primary hepatocytes from treated animals had a reduced ability to internalize LDL than controls. Such a change in the plasma membrane function may explain the resulting hyperlipidemia particularly hypercholesterolemia which occurs in this species as a result of TCDD administration.