Familial renal glycosuria and modifications of glucose renal excretion.

Under physiological conditions, the kidneys contribute to glucose homoeostasis by producing glucose by gluconeogenesis and preventing glucose loss in urine. The glucose filtered by the glomeruli is completely reabsorbed in the renal proximal tubule. Renal gluconeogenesis produces 25% of the circulating glucose in the postabsorptive state, while the amount of glucose reabsorbed by the kidneys largely exceeds the quantity synthesized by kidney gluconeogenesis. Sodium-glucose cotransporter type 2 (SGLT-2) and glucose transporter 2 (GLUT2) carry out more than 90% of renal glucose uptake. In diabetes, both gluconeogenesis and renal glucose reabsorption are increased. The augmentation of glucose uptake in diabetes is due to the overexpression of renal glucose transporters SGLT-2 and GLUT2 in response to the increase in expression of transcription activator hepatic nuclear factor 1-alpha (HNF1α). The rise in glucose uptake contributes to hyperglycaemia and induces glomerular hyperfiltration by increasing sodium and water reabsorption in the proximal tubule that, in turn, modifies urine flux at the macula densa. SGLT-2 inhibitors improve glycaemic control and prevent renal hyperfiltration in diabetes. Loss of SGLT-2 transporter function is a benign state characterized by glycosuria. In contrast, mutations of other glucose transporters expressed in the kidney are responsible for severe disorders.

Serum fructosamine measurement: a new diagnostic approach to renal glucosuria in dogs.

Measurement of serum fructosamine, 1-amino-1-deoxyfructose, is commonly used in diagnosing and monitoring hyperglycaemic disorders, such as diabetes mellitus in dogs. Serum fructosamine indicates long-term serum glucose concentrations and replaces serial serum glucose measurements. This study investigates the clinical usefulness of serum fructosamine in differentiating conditions other than diabetes mellitus characterised by glucosuria. Four dogs presented with glucosuria all had serum fructosamine concentrations within or close to the reference range (313 micromol 1(-1), 291 micromol 1(-1), 348 micromol 1(-1), 262 micromol 1(-1) reference range: 250 to 320 micromol 1(-1) indicating that a single serum fructosamine measurement is a simple and efficient way of verifying concurrent persistent normoglycaemia. Therefore, serum fructosamine is a useful parameter not only in diabetic patients, bu also in differentiating conditions in dogs characterised by glucosuria without hyperglycaemia, such as primary renal glucosuria and the Fanconi syndrome. To distinguish between primary renal glucosuria and the Fanconi syndrome, measurement of the amino acid concentration in urine was performed.

Changes in parathyroid hormone in diabetic patients on long-term hemodialysis.

Changes in parathyroid hormone (PTH) and osteocalcin over 3 years were studied in hemodialyzed patients with diabetic nephropathy (HD/DM) and hemodialyzed patients without diabetes (HD/non-DM). In HD/DM patients, concentrations of the carboxyl terminal regions of PTH and osteocalcin in the serum did not change significantly, but in HD/non-DM patients, both concentrations increased significantly. In patients in both groups, the mean concentration of the mid-region of PTH increased significantly. Secondary hyperparathyroidism in HD/DM develops slower than in HD/non-DM.

[Renal diabetes. Apropos of 103 cases in children]. / Le diabète rénal. A propos de 103 observations chez l'enfant.

A longitudinal study of 103 cases of renal glycosuria (94 families) led to the following conclusions. 1. When the condition is genetically determined, it is probably inherited as an autosomal recessive. 2. There is no relationship with diabetes mellitus. 3. The renal glycosuria is persistent but does not get worse.