Effect of 3-hydroxybutyrate infusion on urinary protein excretion in healthy man

Diabetic ketoacidosis is often associated with a temporary increase in protein excretion, but the mechanisms are not completely known. The aim of the present study was to examine the effect of acute experimental moderate ketosis on kidney function and specifically on protein handling using an infusion of 3-hydroxybutyrate in healthy subjects. Seven young healthy males were infused with sodium 3-hydroxybutyrate, the peak blood level attained being 1.96 +/- 0.53 mmol/l (SD). The pH in blood and urine rose significantly from 7.40 +/- 0.03 to 7.45 +/- 0.05 (2p less than 0.01) and from 7.29 +/- 0.79 to 8.51 +/- 0.82 (2p less than 0.01), respectively. Urinary beta-2-microglobulin excretion rose significantly from 0.038 microgram/min x/ divided by 1.9 to 0.082 microgram/min x/ divided by 1.4 (geometric mean x/ divided by tolerance factor) (2p less than 0.01) but urinary albumin excretion was unchanged. No changes were seen in blood pressure, glomerular filtration rate and renal plasma flow. A marked reduction in urine flow from 15 to 5 ml/min was noted, but could not be attributed to changes in plasma arginine-vasopressin, which was reduced before and during infusion due to considerable oral water loading. It is concluded that moderate elevation in blood ketone body levels does not induce albuminuria. It is suggested that the temporary proteinuria present in diabetic ketoacidosis may be related to acidosis per se.