Abnormal growth hormone levels in insulin-dependent diabetic patients under continuous subcutaneous insulin infusion and intensified conventional treatment.

Abstract

The present study was developed to assess the influence of prolonged blood glucose near normalization, achieved by means of continuous sc insulin infusion (CSII) or intensified conventional therapy (ICT) upon growth hormone (GH) secretion in insulin-dependent diabetes (IDD). Sixteen IDD patients (8 CSII-treated for 3-20 months and 8 under ICT) and 8 healthy control subjects were connected for 24 h to a newly developed, battery-powered glucose monitor. Diabetic patients received their usual food intake and insulin doses. During the second hour after meals moderate exercise, walking at 1.5 km/h, was performed by all subjects. Blood samples for insulin and GH determination were taken before and 60, 120 and 180 min after meal ingestion. Despite a similar degree of previous blood regulation, near normal glucose levels were attained only by the CSII group. Both ICT and CSII patients presented a marked postprandial hyperinsulinaemia. Abnormal GH levels were consistently registered in 4 CSII and 6 ICT patients 120 min after meal initiation. In consequence, both groups showed significantly elevated mean diurnal GH levels (controls: 1.1 +/- 0.3, ICT: 5.2 +/- 0.9, CSII: 4.1 +/- 1.1 ng/ml; P less than 0.05). According to these results, the pathologic GH secretion found in diabetic subjects is not fully normalized by tight control of blood glucose values.