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The thyroid status was studied in 19 uremic patients (11 on HD and 8 on CAPD) and in a group of 17 healthy adult patients. In uremic patients T3 and T4 were significantly reduced (p less than 0.001) and rT3 was increased (p less than 0.001). The time course TSH response to TRH showed a lower peak response (in 5 patients it did not exceed 5 microU/ml) which on turn was also delayed (the peak was observed at 60 minutes in 63% of them). TSH concentrations in uremics were increased at 0 time (p less than 0.02), lower at 20 minutes (p less than 0.01) and increased at 120 minutes (p less than 0.02). No difference existed between HD and CAPD. The thyroid response to TSH was normal as showed by a normal percent increase over basal values of T3 concentrations at 120 minutes. Uremic patients also showed a peak GH response at 20 minutes which was not observed in controls. The data exclude the existence on a primary form of hypothyroidism and point to the existence of hypothalamic-pituitary abnormalities, which should not be taken as indicative of secondary and/or tertiary hypothyroidism since FT4 values were normal in HD and increased in patients undergoing CAPD (p less than 0.05) who on turn showed lower plasma albumin concentrations (p less than 0.05).

Evidence for muscle protein wasting and abnormal muscle metabolism is common in uremia. Muscle DNA content is considered a reliable reference standard in normal and undernourished adults. Muscle RNA content rapidly changes during starvation and refeeding. The ratio of noncollagen alkali-soluble proteins (ASP) to DNA is considered to be an estimate of the cytoplasmic volume of a single cell, and the RNA: DNA ratio is an index of the ribosomal capacity for protein synthesis. Muscle DNA, RNA, ASP, water, and fat content were determined in muscle biopsy specimens from chronically uremic patients receiving conservative treatment (CT), maintenance hemodialysis (two centers), or CAPD. Nutrient intake was low and the anthropometric indices were decreased in all groups of patients, except in the hemodialysis patients from one center. Serum proteins and muscle ASP: DNA and RNA: DNA ratios were decreased. The nutritional status was reassessed in some malnourished CAPD patients after about one year of careful nutritional advice and was unchanged. These results suggest that chronically uremic patients on CT are often malnourished, primarily because of an inadequate protein and/or energy intake. Muscle nucleic acid and protein content are useful tools for nutritional assessment at a cellular level in humans with chronic renal failure and can be used to monitor the response to nutritional therapy.

The kinetics of extra and intracellular red blood cell (RBC) Pi and its removal by different therapeutic modalities were evaluated in 30 uremic patients over a 6 mo. period. Acetate hemodialysis alone, combined with hemoperfusion, or associated once a week with plasma-perfusion sessions using an activated bauxite cartridge, bicarbonate dialysis either in single pass or in recirculating system (40 L) and biofiltration, were the depurative treatments employed. The treatments with acetate buffer showed a temporary intracellular shift of Pi at the end of the sessions with post-dialytic plasma Pi rebound. This was not evident with bicarbonate buffer and biofiltration where acidosis was corrected better, and similarly during plasma perfusion treatment because blood pH remained unchanged. These findings may explain the better plasma Pi level at the end of our study with these later therapeutic models compared to acetate dialysis alone or combined with hemoperfusion. In these conditions Pi removal is limited by the correction of acidosis which implies acetate metabolism with ATP activation leading to a transient Pi intracellular influx and a subsequent efflux into the extracellular compartment.