Biochemical and toxic effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin in immature male and female chickens.

It has been reported that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced body wasting in mammals is associated with decreased adipose tissue lipoprotein lipase (LPL) and glucose transporting (GT) activity with differential sensitivity between genders. This study extends those findings to chickens as an avian model. A significant decrease in body weight gain was demonstrated in immature male and female chickens 10 days after treatment with a single intraperitoneal (i.p.) dose of 10 and 100 microg TCDD/kg. Body weight gain decrease was associated with hepatomegaly and induction of hepatic CYP1A enzymes in both genders. The increase in liver/body weight ratio (48%) and the decreased LPL activity (28%) were significant only in females at 10 microg TCDD/kg. However, the increase in liver/body weight ratio (31%) and the decrease in LPL activity (26%) were significantly demonstrated in males at 100 microg TCDD/kg. Levels of GT were significantly decreased in females (46%) and in males (48%) following treatment with 10 microg TCDD/kg and 100 microg TCDD/kg, respectively. Therefore, in chickens, as in mammals, the TCDD-induced body wasting is accompanied with decreased LPL activity and decreased GT activity and the magnitude of these changes is gender dependent. In contrast to mammals, this study suggests that female chickens are equally, if not more responsive to TCDD toxicity than males.