Comparison of pituitary-thyroid function in patients with end-stage renal disease and in age- and sex-matched controls

The response to i.v. bolus thyrotropin-releasing hormone (TRH) of 14 dialysis patients with end-stage renal disease (ESRD) was compared to the response of 14 age- and sex-matched renal clinic patients (controls) with normal renal function (serum creatinine concentrations <1.2 mg/dl). The mean basal serum levels of thyrotropin (TSH) were similar in the two groups. There was no difference between the two groups in the mean maximal increase in TSH after TRH (6.3 μU/ml and 7.2 μU/ml in ESRD and control groups, respectively); the rate of fall in TSH from 60 to 90 min after TRH was slower in the ESRD group than in the controls. The mean increase in serum triidothyronine (T₃) concentration after TRH was similar in both groups (25.4 ng/dl, ESRD; 18.4 ng/dl, controls). As previously reported, basal serum T₃ content was subnormal in the ESRD patients. Serum thyroxine (T₄) concentrations were comparable in control and ESRD groups and did not change significantly during the 90-min TRH test in either group. We conclude that ESRD patients, clinically stable on dialysis, have normal pituitary TRH responsiveness and normal thyroidal response to endogenous TSH secretion, as compared with an age- and sex-matched group of patients with normal renal function. The results of this study support the contention that ESRD patients are eumetabolic.