Growth hormone in type I diabetic and healthy man.

Conflicting data are found in the literature concerning the growth hormone response to growth hormone-releasing hormone and the insulin-like growth factor I level in Type I diabetes mellitus. The GH response to GHRH and the serum IGF-I level were studied in 29 moderately to well regulated male diabetic patients and 20 age-matched controls. The mean fasting glucose and HbA1c (normal less than 6.5%) levels were, respectively: 10.2 +/- 0.8 mmol/l and 7.1 +/- 0.2%, and 4.1 +/- 0.1 mmol/l and 5.4 +/- 0.1% (mean +/- SEM). The GH response to GHRH was higher in the diabetic patients at 15, 30 and 45 min (p less than 0.05), and also delta peak GH was higher compared with controls: 34.8 +/- 5.6 vs 18.0 +/- 2.4 micrograms/l (p less than 0.02). The serum IGF-I level was lower in the diabetic patients: 460 +/- 30 vs 700 +/- 60 U/l (p less than 0.01). No correlations could be demonstrated between delta peak GH, serum IGF-I or HbA1c level. When only patients with a mean fasting glucose less than or equal to 7.0 mmol/l and normal HbA1c (5.8 +/- 0.3%) were analysed, delta peak GH was also elevated compared with controls: 47.0 +/- 16.3 vs 18.0 +/- 2.4 micrograms/l (p less than 0.02). No difference was observed in GH response or serum IGF-I level in 5 patients with (pre)proliferative retinopathy compared with patients without this complication. It is concluded that in Type I diabetes the GH response to GHRH is increased, even in well regulated patients, and that the serum IGF-I level is depressed.(ABSTRACT TRUNCATED AT 250 WORDS)