Glycemic control reverses increases in urinary excretions of immunoglobulin G and ceruloplasmin in type 2 diabetic patients with normoalbuminuria

To examine whether urinary excretions of plasma proteins with molecular rad ii of 45 - 55 Angstrom and different isoelectric points such as IgG (pl = 7 .4) and ceruloplasmin (pl = 4.4) increase selectively in normoalbuminuric t ype 2 diabetic patients, urinary albumin excretion rate (AER), renal cleara nces of IgG, ceruloplasmin and alpha2-macroglobulin, and creatinine clearan ce (Ccr) were studied in timed overnight urine samples of 36 diabetic outpa tients and 16 control subjects. Furthermore, to examine effect of glycemic control on these urinary protein excretions, the same analysis was performe d before and after glycemic control in 17 diabetic inpatients admitted for glycemic control. Renal clearances of IgG and ceruloplasmin were significan tly higher in diabetic outpatients than in the control group, whereas AER a nd renal clearance of alpha2-macroglobulin did not differ. Glycemic control caused significant decreases in renal clearances of IgG and ceruloplasmin, accompanied with tendency for Ccr to decrease (p = 0.055). The present res ults, together with our previous finding of selectively increased urinary e xcretions of 45 - 55 Angstrom sized plasma proteins in parallel with enhanc ed glomerular filtration rate after acute protein loading, led us to conclu de that enhanced intraglomerular hydraulic pressure may cause increases in clearances of IgG and ceruloplasmin, and that this change can be reversed b y strict glycemic control in normoalbuminuric diabetic patients.