Correlation of Urinary Albumin andβ-2-Microglobulin and Growth Hormone Excretion in Patients with Diabetes Mellitus and Short Stature*

Abstract

We examined the correlation between urinary GH, urinary albumin, and beta-2-microglobulin excretion to determine how the excretion of GH relates to markers of renal glomerular and tubular function. Urinary albumin and GH excretion was determined in timed daytime and nighttime urine collections obtained from both subjects with diabetes mellitus and subjects with short stature. For subjects with diabetes, urinary GH excretion rate correlated highly with urinary albumin concentration and excretion rate in both the range of 0 to 1.6 g/L (r = 0.75), P less than 0.001) and in the microalbuminuria range, 0 to 0.4 g/L (r = 0.53, P less than 0.001). Changes in GH and albumin excretion occurred in parallel in 71% of the subjects with diabetes and elevated albumin excretion. The mean GH excretion rate was higher in the group with elevated albumin excretion rate (AER) during both day and night compared to the group with microalbuminuria during the day and normal AER at night. For subjects with short stature, the mean albumin excretion rate was 0.7 +/- 1.3 micrograms/min (range 0.05-8.3 micrograms/min) using a sensitive enzyme-linked immunosorbent assay to measure albumin concentration. The correlation of GH and albumin excretion rates for the subjects with short stature was not statistically significant (r = 0.14, P less than 0.5). About half of the subjects with diabetes and elevated AER (greater than 10 micrograms/min) had a GH excretion rate within the range observed in subjects with short stature. The GH and albumin excretion rate were not correlated in this group. There was a positive correlation of both albumin and GH excretion rate with age in the subjects with diabetes. Urinary GH and beta-2-microglobulin excretion rates were determined in a larger group of subjects with diabetes and a separate group with short stature. Urinary GH and beta-2-microglobulin excretion were correlated both in subjects with diabetes (r = 0.46, P less than 0.001) and with short stature (r = 0.64, P less than 0.001). The association was present in urine collected either during the day or night. The mean GH excretion rate of the group with diabetes was greater than the group with short stature. In conclusion, there was an association of urinary GH and albumin excretion rate in subjects with abnormal glomerular function as indicated by elevated albumin excretion rate. An association of urinary GH and beta-2-microglobulin excretion was observed in subjects with normal tubular function.(ABSTRACT TRUNCATED AT 400 WORDS)