title: Thyrotoxicity of the chlorides of cadmium and mercury in rabbit.
abstract: Exposure to heavy metals such as cadmium and mercury is of immediate environmental concern. The present study was aimed at establishing a direct relationship between heavy metal poisoning and thyroid dysfunction. Cadmium and mercury treatment at LD50 levels resulted in severe thyrotoxicosis in the rabbit. Within 24 h of intramuscular administration of cadmium chloride 15 mg.kg-1 body weight (bw) and mercury chloride 20 mg.kg-1 bw, thyroid peroxidase activity increased significantly over the control with a concomitant rise in the triiodothyronine (T3) titre. On the other hand, there was a remarkable fall in the thyroxine (T4) level, and the T3/T4 ratio was high as compared with the control. Evidence indicates that acute heavy metal lethality will induce immediate hyperthyroidism. It is suggested that T3-toxicosis may be produced by a preferential synthesis of T3 and/or preferential deiodination of T4 to T3. Measurement of T3 and T4 levels may thus be utilized as a reliable indicator of heavy metal lethality.
authors.affiliation: Department of Zoology, Visva-Bharati University, Santiniketan, India.
authors.forename: N
authors.initials: N
authors.lastname: Ghosh
authors.forename: S
authors.initials: S
authors.lastname: Bhattacharya
mesh_terms: D000818:Animals; D002104:Cadmium / Q000633:toxicity*; D019256:Cadmium Chloride; D002712:Chlorides / Q000633:toxicity*; D007453:Iodide Peroxidase / Q000378:metabolism*; D007928:Lethal Dose 50; D008297:Male; D008627:Mercuric Chloride / Q000633:toxicity*; D011817:Rabbits; D013961:Thyroid Gland / Q000187:drug effects / Q000378:metabolism*; D013974:Thyroxine / Q000378:metabolism; D014284:Triiodothyronine / Q000378:metabolism
chemical_list: D002712:Chlorides; D002104:Cadmium; D014284:Triiodothyronine; D008627:Mercuric Chloride; D007453:Iodide Peroxidase; D019256:Cadmium Chloride; D013974:Thyroxine