title: Early changes in the levels of serum triiodothyronine (T3), thyroxine (T4), T3/T4 ratio and microsomal carboxylesterase activity in rats following treatment with CCL4.
abstract: To study the relationship between the activity of nonspecific carboxylesterase located in the smooth endoplasmic reticulum (SER) of hepatocytes, and serum thyroid hormones including triiodothyronine (T3), thyroxine (T4), and T3/T4 ratio, we determined these hormones, liver carboxylesterase activity, and serum alanine amino-transferase (SGPT) before, and 5 to 720 min after treatment with a single oral dose of CC14 (1 ml/kg) in rats. The serum T3/T4 ratio decreased 5 to 10 min after administration. Each of 16 male and 16 female rats showed a significant correlation between carboxylesterase activity and T3/T4 ratio (male, r = 0.79, p less than 0.01; female, r = 0.84, p less than 0.01), but revealed no correlation between carboxylesterase and T3 or T4, alone. SGPT contents were elevated 6 to 12 h after, whereas T3/T4 ratio decreased gradually during the course. The SER increased mildly 5 min after, but was irregularly distended 6 h after. Changes in the microvilli were not found 5 min after, but the disruption was seen 6 h after. These results suggest that serum T3/T4 ratio is closely correlated with microsomal carboxylesterase activity in CC14-treated rats and represents a microsomal function.
mesh_terms: D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D002251:Carbon Tetrachloride / Q000633:toxicity*; D002265:Carboxylic Ester Hydrolases / Q000032:analysis*; D005260:Female; D008099:Liver / Q000187:drug effects; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology*; D051381:Rats; D011919:Rats, Inbred Strains; D013974:Thyroxine / Q000097:blood*; D014284:Triiodothyronine / Q000097:blood*
chemical_list: D014284:Triiodothyronine; D002251:Carbon Tetrachloride; D000410:Alanine Transaminase; D002265:Carboxylic Ester Hydrolases; D013974:Thyroxine