triiodothyronine--reverse and Uremia

In order to evaluate the effect of zinc (Zn) deficiency on thyroid abnormalities in chronic renal failure, a Zn supplement (100 mg/day, p.o.) was given for four weeks to eight uremic patients under peritoneal dialysis. Zn supplementation increased plasma levels of TSH (5.8 +/- 0.7 to 7.4 +/- 0.7 mU/l, p < 0.02), T4 (61.6 +/- 3.9 to 93.9 +/- 6.2 nmol/l, p < 0.01), T3 (1.31 +/- 0.14 to 1.70 +/- 0.18 nmol/l, p < 0.01) and Zn (7.23 +/- 0.45 to 12.27 +/- 0.76 mumol/l, p < 0.01). A close correlation was found between changes in plasma levels of Zn and changes in TSH (r = 0.82), T4 (r = 0.55) and T3 (r = 0.64), suggesting that Zn deficiency may play a role in the biosynthesis or release of hormones of the hypothalamic-pituitary-thyroid axis in chronic renal failure.

Topics: Adult; Humans; Male; Middle Aged; Peritoneal Dialysis; Thyroid Hormones; Thyrotropin; Thyroxine; Triiodothyronine; Triiodothyronine, Reverse; Uremia; Zinc

Sixty patients with end stage chronic renal failure (CRF) enrolled in a dialysis program underwent studies of serum thyroid hormones and carbohydrate metabolic state. The aim of the study was: 1) to evaluate whether the glucose intolerance per se represents a factor for the alteration of circulating thyroid hormones; and 2) to explore the potential usefulness of specific thyroid hormones and particularly reverse T3 (RT3) as indicators for predicting glucose intolerance. Forty-two patients received hemodialysis and 18 were on intermittent peritoneal dialysis (IPD). CRF patients had reduced serum total T4 and T3 levels, slightly decreased RT3 and TBG concentrations and normal TSH values. There was no significant difference in serum thyroid hormone indices between HD and IPD patients. Glucose intolerance was found in 25 patients. Ten had fasting hyperglycemia and diabetic response to oral glucose tolerance test (OGTT), 15 had an impaired glucose tolerance according to the criteria of the National Diabetes Data Group. In CRF patients with glucose intolerance, serum T3 and T3/T4 molar ratio were significantly lower than in those with a normal OGTT response, whereas serum RT3 and RT3/T4 molar ratio were found to be higher. In the whole group of CRF patients these serum thyroid hormones closely correlated with glucose tolerance indices. To investigate the usefulness of serum RT3 assay in predicting glucose intolerance we compared the outcome of the OGTT and serum RT3 values. Using the results of the OGTT as the true diagnosis of glucose intolerance, serum RT3 assay showed a diagnostic specificity of 94.2% and a sensitivity of 100%. In conclusion these results suggest that: 1) the glucose intolerance, which frequently occurs in uremia, may influence circulating thyroid hormones probably leading to a shift in the peripheral tissue conversion of T4 from T3 to RT3; and 2) serum RT3 assay could assume a clinical interest in assessing carbohydrate metabolic state in treated end stage renal failure independently of the type of dialysis therapy.

Topics: Adult; Aged; Blood Glucose; Female; Glucose Tolerance Test; Humans; Male; Middle Aged; Prognosis; Renal Dialysis; Triiodothyronine, Reverse; Uremia

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)

Topics: Adult; Aged; Body Weight; Chronic Disease; Female; Humans; Infections; Kidney Failure, Chronic; Kinetics; Liver Diseases; Male; Middle Aged; Nutritional Physiological Phenomena; Renal Dialysis; Respiratory Insufficiency; Thyroxine; Triiodothyronine; Triiodothyronine, Reverse; Uremia

Topics: Blood Glucose; Humans; Thyroid Hormones; Triiodothyronine, Reverse; Uremia

Nonthyroidal illness is frequently associated with subnormal serum thyroxine (T4) and free T4 index. To unravel the resultant diagnostic problems, we have studied several variables of thyroid function in the sera of 47 patients hospitalized with nonthyroidal illnesses and seven hypothyroid patients encountered during the same period. Of the 47 euthyroid sick patients, 18 had low T4. Among these 18, free T4 index was normal in only five, whereas free T4 concentration measured by equilibrium dialysis was normal or high in 15 and 3,3',5'-triiodothyronine (reverse T3) normal or high in all 18. Reverse T3, free T4 concentration, and free T4 index were subnormal in all seven hypothyroid patients. Thus, measurement of free T4 index may be misleading in evaluation of thyroid function in patients with nonthyroidal illnesses, whereas measurement of serum concentration of reverse T3 and free T4 is quite discriminating.

Topics: Adult; Aged; Diagnosis, Differential; Diagnostic Errors; Evaluation Studies as Topic; Heart Diseases; Humans; Hypothyroidism; Middle Aged; Neoplasm Metastasis; Neoplasms; Pneumonia; Thyroid Gland; Thyroxine; Triiodothyronine; Triiodothyronine, Reverse; Uremia