EXPRESSION OF THE INSULIN-LIKE-GROWTH-FACTOR-II GENE IN POLYCHLORINATED BIPHENYL EXPOSED FEMALE MINK (MUSTELA-VISON) AND THEIR FETUSES

Aim-To study how polychlorinated biphenyls (PCBs) affect fetal growth and the expression of the insulin-like growth factor (IGF II) gene in the mink (Mustela vison). Methods-Ten female mink were each exposed to 0.65 or 1.3 mg Clophen A50/day, respectively, during the reproductive season. The numbers and sizes of viable fetuses were recorded. The ex pression of the IGF II gene was studied by northern blotting using a m ink specific IGF II cDNA probe. Results-The number of viable fetuses d ecreased after PCB exposure in a dose dependent fashion. Expression of the IGF II gene in adult livers from PCB exposed animals was decrease d, compared with control animals, in a dose dependent fashion. In cont rast, IGF II expression in placentas and fetuses was unaltered. Furthe rmore, the maternal excretion of urinary cortisol increased in both ex posed groups during the implantation period. Conclusions-Expression of the IGF II gene is downregulated by PCB exposure in the adult Liver. There is also an indication that the regulation of the expression of t his gene differs between adult and fetal life.