Effect of long-acting somatostatin analog (Somatulin) on renal hyperfiltration in patients with IDDM

OBJECTIVE - To investigate whether long-acting somatostatin (SMS) can suppress renal hyperfiltration in patients with IDDM. RESEARCH DESIGN AND METHODS - A double-blind, randomized treatment of nine patients with IDDM was used. Selection criteria were renal hyperfiltration (glomerular filtration rate [GFR] greater than or equal to 129 ml . min(-1) 1.73 m(2)) and absence of hypertension and macroalbuminuria. Treatment was either with a long-acting SMS analog (Somatulin, 30 mg) or with placebo, given by intramuscular injections every 10 days for 9 months. GFR, effective renal plasma flow (ERPF), IGF-I, and 24-h growth hormone (GH) profiles were used as evaluation parameters. RESULTS - Five patients were randomized to Somatulin, four patients to placebo. One of the patients treated with Somatulin stopped after 3 months because of persistent abdominal discomfort after the injections. Somatulin treatment for 3 months lowered GFR and ERPF compared with placebo (P < 0.05). After 9 months, the differences were no longer significant. After 3 months, IGF-I concentrations were decreased in all Somatulin-treated patients. GH secretion tended to increase in the placebo group. CONCLUSIONS - The administration of long-acting Somatulin to patients with IDDM and renal hyperfiltration leads to only a temporary reduction of ERPF/GFR.