[Diabetes mellitus: renal osmoregulating function].
OBJECTIVE
To evaluate the kidney status from osmotic urine concentration in different stages of diabetes mellitus (DM) to define whether not only glomeruli and proximal tubules, but also renal medullary substance structures are involved into the pathological process, as well as their reaction to endogenous vasopressin production.


METHODS
Forty patients with a 1-to-28-year history of DM, including 18 with diabetic nephropathy, 10 with chronic renal failure, and 22 without diabetic nephropathy, were examined. Urine and blood osmolality were determined and renal osmoregulating function was estimated.


RESULTS
Decreased glomerular filtration rate was found in relation to the duration of DM. The osmolality of nocturnal urine samples tended to diminish during short-term deprivation depending on the duration of DM. Increased diuresis in DM was shown to correlate with the higher reabsorption of osmotically free water.


CONCLUSIONS
Diminished renal concentrating capacity in DM appears to depend on evolving renal failure rather than vasopressin resistance. The application of a new approach, by calculating the clearance of sodium-free water, suggests that its increased reabsorption favors normalization of serum osmolality in hyperglycemia.
Natochin
Iu V
IuV
Shestakova
M V
MV
Kuznetsova
A A
AA
Klefortova
I I
II
Trubitsyna
N P
NP
Dedov
I I
II
D000328:Adult; D000368:Aged; D003920:Diabetes Mellitus / Q000097:blood / Q000503:physiopathology* / Q000652:urine; D003928:Diabetic Nephropathies / Q000097:blood / Q000503:physiopathology* / Q000652:urine; D005260:Female; D006801:Humans; D007668:Kidney / Q000503:physiopathology*; D007671:Kidney Concentrating Ability / Q000187:drug effects / Q000502:physiology*; D007676:Kidney Failure, Chronic / Q000097:blood / Q000503:physiopathology* / Q000652:urine; D007677:Kidney Function Tests; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D016482:Urinalysis; D014556:Urine / Q000737:chemistry; D055815:Young Adult