Secretion of growth hormone in the insulin test, and the development of diabetic microangiopathy.

Serum growth hormone (HGH) was determined in: 1) diabetics without retinopathy, 2) diabetics with retinopathy and normal creatinine clearance. In diabetes without retinopathy the HGH was higher than in controls, while in the group of cases with retinopathy the HGH level was significantly lower than in the group without vascular changes and in the control group. Cases with retinal vascular changes and reduced creatinine clearance had a significantly higher HGH level as compared with the group with normal clearance, and the dynamics of HGH secretion in the group with reduced clearance differed from those in the remaining groups. This pattern of HGH secretion in the studied groups showed a connection between raised HGH level and impairment of renal function developing when vascular changes appear in diabetics.