The metabolism of 3,3'-diiodothyronine in man

The production rate of 3,3'-Diiodothyronine (3,3'-T2) was measured in five healthy subjects after a single injection of [125I]3,3'-T2. The [125I]3,3'-T2 was measured by immunoprecipitation. To reduce the large amount of nonspecific serum radioactivity (iodides, 3,3'-T2 metabolites, and protein-bound iodine), the sear were treated before the immunoprecipitation with an anion exchanger and polyethylene glycol (final concentration, 10%). The noncompartmental analysis of the data gave the following results: MCR, 0.52 +/- 0.07 liters/min or 926 +/- 142 liters/day (mean +/- SD); and production rate, 23.7 +/- 8.2 ng/min or 34 +/- 12 micrograms/day.