Enhanced thyroxine metabolism in hexachlorobenzene-intoxicated rats.
The effect of hexachlorobenzene (HCB) (1 g/kg bw) administration for 4 weeks, on thyroxine (T4) and triiodothyronine (T3) metabolism was studied in Wistar rats. The effect on serum binding of T4 has also been studied. Animals were injected with a tracer dose of either labeled hormone and by examining serum L-125I-T4 and L-125-I-T3, kinetics of radiolabeled hormones metabolism were calculated. The T4 metabolic clearance (MCI) as well as the distribution space, were increased by 6 fold. Decreased serum T4 levels result from an increase both in deiodinative and fecal disposal in HCB-treated rats. 125I-T3 metabolism was slightly affected. The enhanced peripheral disposition of thyroxine appears to lead to increased thyroid function, as measured by augmented TSH serum levels and 125I-thyroidal uptake. Serum binding of T4 was not affected.
Kleiman de Pisarev
D L
DL
Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina.
Sancovich
H A
HA
Ferramola de Sancovich
A M
AM
D000818:Animals; D001798:Blood Proteins / Q000378:metabolism; D002722:Chlorobenzenes / Q000633:toxicity*; D005260:Female; D006581:Hexachlorobenzene / Q000633:toxicity*; D007457:Iodine Radioisotopes; D051381:Rats; D011919:Rats, Inbred Strains; D013961:Thyroid Gland / Q000378:metabolism; D013974:Thyroxine / Q000097:blood / Q000378:metabolism*; D014284:Triiodothyronine / Q000097:blood / Q000378:metabolism
D001798:Blood Proteins; D002722:Chlorobenzenes; D007457:Iodine Radioisotopes; D014284:Triiodothyronine; D006581:Hexachlorobenzene; D013974:Thyroxine