Comparative effects of pair-feeding and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on various biochemical parameters in female rats.
Hypophagia is a common characteristic of the toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and may be responsible for some of the toxic manifestations. Pair-feeding has been used in control animals to compensate for the hypophagia, but relatively few studies have assessed biochemical changes associated with pair-feeding versus weight loss induced by TCDD. Rats were treated with TCDD and killed 7 days post-treatment while pair-fed animals received an amount of diet equivalent to TCDD-treated partner animals. Ad libitum-fed rats were also used. No correlations were seen in altered calcium and iron homeostasis between pair-feeding and TCDD administration relative to ad libitum-fed animals. Pair-feeding resulted in greater alterations than TCDD administration in the subcellular distribution of iron in mitochondria, microsomes and cytosol. Pair-feeding also resulted in greater accumulation of calcium in mitochondria and microsomes in pair-fed as compared to TCDD-treated animals. Greater lipid peroxidation was observed in whole liver and nuclei of rats receiving TCDD relative to pair-fed animals. A significantly greater incidence of DNA single strand breaks occurred in hepatic nuclei of TCDD-treated animals as compared to pair-fed and ad libitum-fed animals. Significantly greater inhibition of hepatic glutathione peroxidase activity and thymic involution were observed in TCDD treated animals as compared to the pair-fed group. Although some similarities existed between TCDD-treated animals and pair-fed rats, the overall biochemical changes which were observed following TCDD administration cannot be attributed to weight loss associated with hypophagia.
Wahba
Z Z
ZZ
Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha.
Murray
W J
WJ
Hassan
M Q
MQ
Stohs
S J
SJ
D000818:Animals; D002118:Calcium / Q000378:metabolism; D004247:DNA / Q000187:drug effects; D004249:DNA Damage; D004147:Dioxins / Q000633:toxicity*; D004435:Eating / Q000187:drug effects*; D005260:Female; D007501:Iron / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D009929:Organ Size / Q000187:drug effects; D000072317:Polychlorinated Dibenzodioxins / Q000633:toxicity*; D051381:Rats; D011919:Rats, Inbred Strains; D013950:Thymus Gland / Q000187:drug effects; D015431:Weight Loss / Q000187:drug effects*
D004147:Dioxins; D000072317:Polychlorinated Dibenzodioxins; D004247:DNA; D007501:Iron; D002118:Calcium