Renal and hormonal responses were studied in a group of healthy individuals fed, in random order, for three weeks, a vegetable protein diet (N = 10), an animal protein diet (N = 10), or an animal protein diet supplemented with fiber (N = 7), all containing the same amount of total protein (chronic study). In seven additional subjects the acute renal, metabolic and hormonal response to ingestion of a meat or soya load of equivalent total protein content was investigated (acute study). In the chronic study GRF, RPF and fractional clearance of albumin and IgG were significantly higher on the animal than the vegetable protein diets (GFR: 121 +/- 4 vs. 111 +/- 4 ml/min/1.73 m2, P less than 0.001; RPF: 634 +/- 29 vs. 559 +/- 26 ml/min/1.73 m2, P less than 0.001; theta alb: 19.5 +/- 3.1 vs. 10.2 +/- 1.6 x 10(-7), P less than 0.01; theta IgG: 11.6 +/- 3.1 vs. 7.5 +/- 1.7 x 10(-7), P less than 0.05). Renal vascular resistance was lower on the animal than vegetable protein diet (82 +/- 5 vs. 97 +/- 5 mmHg/min/liter; P less than 0.001). Fiber supplementation to APD did not have any effect on the renal variables measured which were indistinguishable from APD. In the acute study, GFR and RPF both rose significantly by approximately 16% (P less than 0.005) and approximately 14% (P less than 0.05), respectively, after the meat load, while RVR fell by approximately 12% (P less than 0.05). There were no significant changes in these parameters following the soya load.(ABSTRACT TRUNCATED AT 250 WORDS)

Glomerular hyperfiltration has been claimed to be a risk factor for the development of diabetic nephropathy. Protein intake and hyperglycemia can both increase GFR in diabetic and normal subjects. Our study was designed to explore the relative importance of short-term changes in protein intake and glycemia on the modulation of renal hemodynamics in insulin-dependent diabetic (IDDM) patients with and without glomerular hyperfiltration. The renal hemodynamic response to a protein challenge was studied in eight hyperfiltering (HF) and eight normofiltering (NF) patients after a three week period of low or normal protein diet (LPD, NPD), each study being conducted twice, in random order, under conditions of prevailing hyperglycemia (H) and euglycemia (E). In HF patients GFR failed to increase significantly in response to protein challenge during NPD under conditions of either H or E (Baseline vs. 2 hr H: 151 +/- 4 vs. 155 +/- 6, NS; E 147 +/- 4 vs. 157 +/- 7 ml/min/1.73 m2, NS). A more normal response was restored following LPD with GFR increasing in all but one patient after challenge during H and in all patients during E (Baseline vs. 2 hr H: 130 +/- 7 vs. 145 +/- 8, P less than 0.07; E: 127 +/- 7 vs. 143 +/- 7 ml/min/1.73 m2, P less than 0.01). Changes in RPF paralleled the changes in GFR and filtration fraction remained stable under all study conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Renal function studies were performed in 41 patients with sickle cell-β thalassaemia (S/b thai) and compared to 14 normal controls and 8 sickle cell (SS) patients. Polyuria, hyposthenuria and mild proteinuria were common in both S/b thai and SS patients. A renal concentrating defect was manifest in all patients studied, and in 4 of the 7 S/b thai patients tested, an abnormal acidification test was found. A statistically significant negative correlation (n=19, r = -0.48, p < 0.05) was noted between creatinine clearance (CCr) and age for the patients over 30 years. There was no correlation between hemoglobin and CCr; on the contrary, a statistically significant negative correlation was found between CCr and hemoglobin F (n = 29, r=-0.428, p < 0.05) Our S/b thai and SS patients showed a decreased daily excretion of sodium, calcium, phosphate and magnesium and lower serum magnesium levels than the controls. One third of the S/b thai patients showed hyperuricosuria, and a statistically significant negative correlation was noted between serum uric acid and its fractional excretion in all S/b thai patients (n = 41, r = -0.450, p < 0.01). Serum phosphate levels were independent of age. A statistically significant positive correlation was found between the tubular reabsorptive capacity for phosphate and the number of painful crises per year (n = 33, r = 0.836, p < 0.001). We conclude that renal involvement in the double heterozygous state is as severe as in homozygous sickle cell disease.

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