Evaluation and Clinical Applications of Measurement of Urinary Growth Hormone in Diabetic Subjects

Quantities of growth hormone (GH) excreted into the urine over 24 h were measured by the highly sensitive sandwich enzyme immunoassay in 63 non-insulin-dependent diabetes mellitus (NIDDM) subjects, 6 insulin-dependent diabetes mellitus (IDDM) subjects, and 17 age-matched nondiabetic control subjects. GH-provocative tests with intravenous infusion of arginine revealed that urinary GH levels are closely correlated with the integrated concentrations of serum GH (r = .931, n = 14, P < .001). Furthermore, 24-h urinary GH in control and diabetic subjects was inversely related to body mass index (r = .359, n = 80, P < .001). The mean 24-h urinary GH in NIDDM subjects was 11.1 ± 1.9 ng/g creatinine (Cr), which was not significantly different from that in nondiabetic control subjects (9.2 ± 2.7 ng/g Cr). By contrast, the individual values for IDDM subjects varied widely, and their mean values (42.5 ± 20.8 ng/g Cr) were much greater than those in the control and NIDDM subjects (P < .01). The degree of glycemic control does not seem to affect 24-h urinary GH in NIDDM. The mean 24-h urinary GH in 7 subjects with proliferative diabetic retinopathy was comparable to that in subjects without retinopathy or with background retinopathy. Thus, the measurement of 24-h urinary GH appears to provide reliable assessments of endogenous GH secretion under physiological conditions and will be a useful tool for obtaining further insight into the role of GH in diabetes.