Effects of variation of the tri-iodothyronine/reverse triiodothyronine ratio in vivo on the metabolic characteristics of subsequently isolated hepatocytes.
Reverse tri-iodothyronine (3,3',5'-tri-iodothyronine, rT3), a major product of the peripheral monodeiodination of thyroxine, was administered subcutaneously to fed rats at a dose of 100 micrograms/100 g body weight for 2 consecutive days. This dose induced a 17-fold increase in plasma rT3 (from 0.05 +/- SEM 0.01 to 0.85 +/- 0.11 ng/ml, P less than 0.001) whilst the plasma T3 concentration was decreased to half of the control value (0.40 +/- 0.03 to 0.20 +/- 0.02 ng/ml, P less than 0.01). As a result of these changes the T3/rT3 ratio was therefore decreased from 8.0 +/- 1.6 to 0.23 +/- 0.03 (P less than 0.001). Hepatocytes prepared from control or rT3-treated rats were incubated with [1-14C]oleate and the rates of 14CO2 release and glucose production were estimated. Despite the changes in ratio of T3 to rT3 observed in vivo, rates of 14CO2 release and glucose production rate from hepatocytes subsequently isolated were unchanged.
D000818:Animals; D002245:Carbon Dioxide / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D007279:Injections, Subcutaneous; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D014284:Triiodothyronine / Q000008:administration & dosage* / Q000097:blood; D014285:Triiodothyronine, Reverse / Q000008:administration & dosage* / Q000097:blood
D014284:Triiodothyronine; D002245:Carbon Dioxide; D014285:Triiodothyronine, Reverse; D005947:Glucose