The hypophosphatemic and hyperkalemic effect of arginine in man

The effects of a 0.5 g/kg body weight arginine infusion on plasma inorganic phosphate and potassium were examined in 15 normal subjects, and 6 recently diagnosed insulinopenic diabetics. Plasma phosphorus displayed a highly significant (p less than 0.001) fall in normal subjects, with a maximum fall below the baseline of 1.11 +/- 0.15 mg/100 ml or 33 + 3% (mean +/- SE). In addition, there was a highly significant correlation (p less than 0.01) between these falls and the insulin peaks induced by arginine. Plasma potassium levels, on the other hand, displayed a distinct and significant increase in 7 of the 8 subjects studied in this connection. The maximum increase over the baseline was 1.23 +/- 0.17 meq/l or 33 +/- 6% (p less than 0.01). In diabetic patients, arginine too led to a fall in phosphorus. While this was still significant, it was clearly less than in normal subjects: maximum fall = 0.64 +/- 0.09 mg/100 ml or 15 +/- 3%. Plasma potassium increased to a greater extent than in normal subjects: maximum increase = 1.63 +/- 0.21 meq/l or 42 +/- 6%. These findings show that arginine is responsible for a fall in plasma phosphorus that may well be partly related to the insulin response, and an increase in plasma potassium of clinical significance, whose mechanism(s), however, are still obscure.