GLUCOSE-TOLERANCE DURING PROGRESSION OF CHRONIC-RENAL-FAILURE

Glucose tolerance (GT) and insulin (I) levels were examined after an oral glucose (G) load (75g) in 45 patients with chronic renal failure (CRF) (26 M, 19 F aged 60 +/- 10 years) divided into four groups according to dietary regimen and serum creatinine (sCr). Three groups (CRF-I: sCr>1.5-less than or equal to 3 mg/dl; CRF-II: sCr>3-less than or equal to 6 mg/dl; CRF-III: sCr>6 mg/dl) followed a conventional low-protein diet (CD), and the fourth (CRF-IV: sCr>4.5 mg/dl) comprised patients on a vegetarian supplemented diet (SD). Before the test, patients were examined for PTH levels. The effects of progressive CRF, diet (CD vs SD) and PTH were investigated in comparison with a control group (n=12; 8 M, 4 F aged 47+/-8 years). G levels were significantly higher at T90 and T120 in patients with advanced renal failure (CRF-III and CRF-IV) regardless of the diet. However, I levels were increased at T90 and T120 from early renal insufficiency and further increased with the progression of CRF. Despite the increase, I secretion was still inadequate to overcome the insulin-resistant state and maintain GT in patients with advanced renal failure (CRF-III and CRF-IV). PTH was significantly increased in groups I-III. Despite the almost normal PTH concentration and higher I levels than the CD group, SD patients still had impaired GT. Our results indicate that patients on SD do not have better GT than patients on CD and suggest secondary hyperparathyroidism as only one of the many contributory factors affecting insulin release and GT in uremia.