The kinetics of the thyroid hormones and the peripheral conversion rate of thyroxine to triiodothyronine in acute liver insufficiency under experimental conditions.
The kinetics of triiodothyronine (T3) and thyroxine (T4) were studied in 20 ewes. Ten were used as the control group, the other 10 received massive hepatic lesions induced by the ingestion of carbon tetrachloride. Half of each group were i.v. injected with 125IT3 or 125IT4, following a plasma disappearance over 96 hours. The amount of hormone present in each plasma sample was determined by immunoextraction procedure. The data was adjusted to the open two-compartment model. The hepatic insufficiency provoked a decrease in the disposition consent of T3, an increase in th plasma half-life of the distribution phase as well as a moderately decreased turnover rate of this hormone. The T4 kinetics were altered during acute hepatic insufficiency in the decrease of the elimination constant K13 and hormone plasma turnover rate. The study of the peripheral conversion rate based on the kinetic data showed an extrathyroidal conversion of T4 to T3 in the control sheep, none being detected in the sheep with induced hepatic insufficiency.
D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood; D001663:Bilirubin / Q000097:blood; D002252:Carbon Tetrachloride Poisoning / Q000378:metabolism*; D005260:Female; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D008657:Metabolic Clearance Rate; D012756:Sheep; D013974:Thyroxine / Q000378:metabolism*; D014284:Triiodothyronine / Q000378:metabolism*
D014284:Triiodothyronine; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D013974:Thyroxine; D001663:Bilirubin