The transcapillary escape rate and relative plasma disappearance of glycated and 
non-glycated albumin were measured in 25 male Type 1 (insulin-dependent) 
diabetic patients using a double tracer technique. The patients were divided 
into three groups on the basis of their urinary albumin excretion: group 1, 
normal albumin excretion (less than 30 mg/24 h) (n = 8); group 2, 
microalbuminuria (30-300 mg/24 h) (n = 9); and group 3, clinical nephropathy 
(greater than 300 mg/24 h) (n = 8). Six male age-matched non-diabetic persons 
served as control subjects. The transcapillary escape rate of glycated albumin 
was similar in group 1 and control subjects (4.7 +/- 2.1 versus 5.1 +/- 1.7%), 
but significantly increased in group 2 (7.0 +/- 1.7%, p less than 0.05) and in 
group 3 (7.9 +/- 3.1%, p less than 0.05). The transcapillary escape rate of 
glycated albumin was slightly lower than that of non-glycated albumin in all 
groups, but significant only in normal control subjects. No difference in the 
catabolic rate of glycated and non-glycated albumin was found. We conclude that 
the in vivo effects of glycation on the clearance and transcapillary passage of 
albumin are small and not likely to play any significant role in the development 
of late diabetic microvascular complications.