title: Metabolic clearance of endogenous and radioiodinated thyroglobulin in rats.
abstract: The basal concentration and metabolic clearance of radiolabeled and endogenous thyroglobulin (Tg) were measured in normal male rats. Serum Tg concentrations (by RIA) in Sprague-Dawley adult males ranged from 70-680 ng/ml (mean +/- SD, 218 +/- 177). In male Fisher rats, basal serum Tg concentrations were 32-263 ng/ml. The fractional disappearance rate of endogenously radioiodinated rat Tg and of endogenous rat Tg after thyroidectomy were both about 8%/h. The MCR of endogenously labeled Tg was 2.4 +/- 1.1 ml/100 g/h. Using this clearance and the mean serum Tg concentration in these rats, a daily thyroidal release rate of about 201 microgram Tg/100 g BW would be required to provide the T4 metabolized daily by the rat, the Tg released into the circulation comprises about 7% of the total rat Tg produced in a 24-h period.
mesh_terms: D000818:Animals; D007457:Iodine Radioisotopes; D007553:Isotope Labeling; D007700:Kinetics; D008297:Male; D008657:Metabolic Clearance Rate; D011863:Radioimmunoassay; D051381:Rats; D013954:Thyroglobulin / Q000378:metabolism*; D013965:Thyroidectomy
chemical_list: D007457:Iodine Radioisotopes; D013954:Thyroglobulin