[Relations between oral glucose load and urinary elimination of calcium and phosphorus in healthy men with normal body weight].

Serum and urinary glucose, creatinine, calcium and phosphorus, serum insulin were measured every 60 min from 9.00 to 12.00 in twenty healthy subjects. All subjects presented normal body weight, renal function, serum glucose, serum and urinary calcium. Urinary calcium and phosphorus were expressed by Ca/creat and P/creat ratio, and renal phosphate threshold was expressed by the TmP/GFR ratio. At 9.00, after an overnight fast, ten subjects received 75 g of glucose (groupe B) and ten subjects were conserved as controls (group A). Hyperglycemia and hyperinsulinemia due to glucose load (B) induce a decrease of serum phosphorus (10.00, 11.00, 12.00), while phosphoremia increased in group A. Urinary P/creat increased in group A (12.00), and decreased in group B (12.00); while TmP/GFR decreased in group B (10.00, 11.00). Serum calcium rose in the two groups, according to the circadian rythm and urinary Ca/creat ratio increased in group A (10.00) and increased considerably in group B (10.00, 11.00, 12.00). In group B, a negative linear correlation was found between serum glucose and TmP/GFR ratio (= -0,50) and between serum phosphorus and urinary Ca/creat ratio (r = -0,40). These results show that in healthy subjects, with normal body weight, oral glucose load induced a decrease of phosphaturia and an increase of calciuria, subsequent to hyperglycemia.