No Evidence For Increased Growth Hormone Responses to Growth Hormone-Releasing Hormone in Patients With Diabetic Retinopathy

Several studies report increased growth hormone (GH) responses to provocative stimuli in patients with diabetic retinopathy. We studied GH responses to 1 μg/ kg body wt human pancreatic GH-releasing hormone 1-44 (hpGHRH 1-44) in 33 patients with type I diabetes mellitus, 31 patients with type II diabetes mellitus, and 2 control groups (N = 11 and 8). Based on the results of fundoscopy and fluorescein angiography, the diabetic patients were subdivided into 1) patients without diabetic retinopathy, 2) patients with nonproliferative diabetic retinopathy, and 3) patients with proliferative diabetic retinopathy. Growth hormone responses to hpGHRH 1-44 in diabetic patients with proliferative or nonproliferative retinopathy or without retinopathy were not significantly different regardless of the type of diabetes. Remarkably, GH responses to hpGHRH 1-44 in type I diabetic patients without retinopathy were significantly higher than the matched controls. Our data suggest that diabetic retinopathy in type I and in type II diabetes isnot associated with increased GH responsiveness to hpGHRH 1-44, whereas in type I diabetes mellitus without diabetic retinopathy, a GH hyperresponsiveness to hpGHRH seems to occur.