Summary
Growth hormone (GH) hypersecretion is well documented in insulin-dependent diabetes mellitus (IDDM). Somatostatin inhibits GH in acromegalics and healthy subjects although data on its inhibitory effects on high GH levels in IDDM patients are controversial.
The effect of treatment with the Somatostatin analogue octreotide (“Sandostatin”) on GH secretion, IGF1 levels and metabolic control was investigated in insulin-dependent diabetics.
Growth hormone and blood glucose were measured at hourly intervals whilst IGF-I was measured every 6 hours during the 24-h period before and after 7 days' treatment with octreotide (200 μg subcutaneously three times daily) in 10 C-peptide negative diabetics.
Octreotide significantly reduced mean 24 h GH profile (7.2±0.7 mU/L before; 5.2±0.5 mU/L on octreotide, p < 0.01), IGF-I levels (0.62±0.06 before; 0.47±0.05 on octreotide, p < 0.005) mean 24 h blood glucose (14.4±0.5 mmol/L before; 12.6±0.4 mmol/L on octreotide, p < 0.001) and daily insulin requirements (44.8±3.0 IU before; 37.2±3.0 IU on octreotide, p < 0.02). The shape of 24 h GH profile curve changed significantly on octreotide treatment (p < 0.05) when it consisted of three nadirs and three peaks closely linked with the time of octreotide administration.
Moderate (abdominal discomfort) to severe (hypoglycaemia) transient side effects have been observed in all treated patients.
The results of this study showed that short-term treatment with octreotide given s. c. every eight hours modulates the pattern of GH secretion in C-peptide negative insulin-dependent patients. We hypothesize that these changes are the result of a dual effect of octreotide on pituitary somatotropes (inhibitory and priming) and possibly also, altered pharmacokinetics of octreotide in insulin-dependent diabetics.
Key words
Insulin-Dependent Diabetes Mellitus - Residual Beta Cell Function - Growth Hormone - Blood Glucose - Octreotide
