Alterations of serum reverse triiodothyronine and thyroxine kinetics in chronic renal failure: role of nutritional status, chronic illness, uremia, and hemodialysis.
ātients with end-stage chronic renal failure (CRF) and those receiving dialysis therapy have normal or decreased serum total T4 (TT4), reduced serum total T3 (TT3), and normal total reverse T3 (TrT3) levels. Those with nonrenal nonthyroidal illnesses or malnutrition have low TT4 and TT3 but elevated TrT3 values. To evaluate the mechanism(s) for the normal TrT3 levels in CRF, we performed intravenous bolus kinetic studies of rT3 and T4 in patients with CRF, in those treated with chronic hemodialysis, in patients with nonrenal nonthyroidal illnesses, and in normal subjects. The CRF patients were selected to have good nutritional status as indicated by normal serum transferrin, relative body weight, and body mass index values. The CRF patients had normal TrT3, TT4, and free T4 values, increased free fraction of rT3, free rT3, and thyroxine-binding globulin levels, and decreased TT3 concentrations. Noncompartmental analysis of the rT3 kinetics indicated normal production rate, reduced cellular clearance rate, and increased pool size and residence time values in both the CRF and nonrenal patients. In CRF, the serum clearance rate was normal, but the fractional rate of exit, permeability, extravascular binding, and the apparent volume of distribution were increased. In contrast, the nonrenal patients had reduced serum clearance rate, permeability, and extravascular binding, whereas the fractional rate of exit and apparent volume of distribution were not significantly altered. The T4 kinetics in CRF paralleled those of the nonrenal patients, with a reduced fractional rate of exit and permeability in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)
D000328:Adult; D000368:Aged; D001835:Body Weight; D002908:Chronic Disease; D005260:Female; D006801:Humans; D007239:Infections / Q000097:blood; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000628:therapy; D007700:Kinetics; D008107:Liver Diseases / Q000097:blood; D008297:Male; D008875:Middle Aged; D009747:Nutritional Physiological Phenomena; D006435:Renal Dialysis; D012131:Respiratory Insufficiency / Q000097:blood; D013974:Thyroxine / Q000097:blood*; D014284:Triiodothyronine / Q000097:blood*; D014285:Triiodothyronine, Reverse / Q000097:blood*; D014511:Uremia / Q000097:blood
D014284:Triiodothyronine; D014285:Triiodothyronine, Reverse; D013974:Thyroxine