Sandostatin, a new analogue of somatostatin, reduces the metabolic changes induced by the nocturnal interruption of continuous subcutaneous insulin infusion in type 1 (insulin-dependent) diabetic patients

Effects of octreotide on glycaemic control, glucose disposal, hepatic glucose production and counterregulatory hormones secretion in type 1 and type 2 insulin treated diabetic patients

We studied the effects of continuous subcutaneous infusion of octreotide (100 micrograms/day for 5 days) on glycaemic values, counterregulatory hormones secretion, hepatic glucose production (HGP) and glucose disposal during an euglycaemic clamp in 7 C-peptide-negative type 1 diabetic patients and 7 C-peptide positive insulin-treated type 2 diabetic patients. In type 1, but not type 2 diabetic patients, octreotide significantly reduced glycaemic values (P < 0.005) and also diminished HGP during an euglycaemic clamp (P < 0.05). However, insulin stimulated global glucose uptake remained unchanged. GH, glucagon, IGF-I, IGFBP-3 levels, were significantly lowered by octreotide in both type 1 and type 2 diabetic patients whereas cortisol and epinephrine remained unmodified. Moreover in type 2 diabetic patients both basal (P < 0.05) and after-meal (P < 0.01) C-peptide secretion was reduced by octreotide. These data point to different metabolic effects of octreotide in type 1 versus type 2 diabetic patients with the drug only being able to reduce glycaemic values and HGP in the former but not in the latter subjects. The failure of octreotide to diminish glycaemic values and HGP in type 2 diabetic patients in spite of its ability to lower GH and glucagon may probably depend on temporary blockage of residual endogenous insulin secretion induced by octreotide administration.

Effect of the new somatostatin analogue SMS 201-995 on exogenously used insulin

Somatostatin and somatostatin analogues are inhibitors of insulin, glucagon, and growth hormone secretion. However, it has not been determined whether it is somatostatin or its analogues which affect these hormones when used concomitantly. The effect of the somatostatin analogue SMS 201-995 on exogenously infused insulin was observed in ten healthy volunteers. The study was carried out on two occasions with at least a 1-week interval. Each subject was infused with saline throughout the study and insulin at a rate of 40 mU/kg per hour between 60-160 min of the study (step A) or SMS 201-995 in a 75 micrograms IV bolus following at a rate of 75 micrograms/h for 160 min and insulin at the same rate and duration (step B). Hyper-insulinemia and SMS 201-995 significantly suppressed C-peptide secretion, but the degree of C-peptide suppression was greater in the SMS 201-995 infused step than in the insulin-only infused step. Blood glucose levels decreased markedly throughout the infusion of insulin with or without SMS 201-995. In step B, the decrease in blood glucose was greater than in step A. Insulin levels in step B increased to higher levels than in step A (from 81.1 +/- 7.7 to 363.9 +/- 22.7 mmol/l and from 82.7 +/- 8.6 to 229.0 +/- 23.4 mmol/l, respectively). These results show that SMS 201-995 increases the level of exogenously infused insulin. This is probably due to the impaired clearance of exogenous insulin.

The effect of various blood glucose levels on post-glucagon C-peptide secretion in type 2 (non insulin-dependent) diabetes

We investigated how different plasma glucose concentrations could significantly modify the C-peptide response to glucagon. Twenty poorly-controlled (HbA1c 10.2 +/- 1.5%) non insulin-dependent (NIDDM) subjects (body mass index 27 +/- 1.8), 2 treated with diet alone and 18 with oral hypoglycemic agents were studied. The first day glucagon (1 mg iv) was injected, patients being fasting and untreated. Mean plasma glucose levels were 11.4 +/- 1.2 mM. On a second non consecutive day, after an overnight fast, the same patients were connected to a closed-loop insulin infusion system (Betalike, Genoa), their blood glucose concentrations were stabilized within a normoglycemic range (5-5.5 mM) for 2 h and insulin infusion was stopped. The glucagon test was repeated 30 min later. Blood samples were taken 0, 6, 10, 20 min after glucagon injection. In the second test, basal, and 6, 10 and 20 min post-glucagon glucose levels were significantly lower (p less than 0.001); similarly C-peptide concentrations were significantly reduced both in basal conditions (0.55 +/- 0.04 vs 0.37 +/- 0.04 nM; p less than 0.001) and 6 (0.92 +/- 0.06 vs 0.6 +/- 0.06; p less than 0.001), 10 (0.79 +/- 0.06 vs 0.56 +/- 0.06; p less than 0.001) and 20 min (0.64 +/- 0.05 vs 0.44 +/- 0.04; p less than 0.001) after stimulation. The C-peptide secretion area showed the same trend (49.5 +/- 4.8 vs 32.1 +/- 5.8; p less than 0.001). In conclusion, our data confirms that blood glucose levels modulate the pancreatic insulin secretion; glycemic normalization significantly reduced both basal and post-glucagon C-peptide release.

Preventive effects of octreotide (SMS 201-995) on diabetic ketogenesis during insulin withdrawal

1. Exogenous somatostatin inhibits glucagon secretion and prevents ketoacidosis in diabetic patients, but has the therapeutic disadvantage of requiring continuous intravenous infusion to exhibit these effects. 2. Consequently, we examined the effect of subcutaneous administration of the long-acting somatostatin analogue octreotide (SMS 201-995) on early ketogenesis in diabetic ketoacidosis. On two separate occasions insulin was withdrawn over a period of 9 h from seven type I diabetic patients. On the second occasion the patients were given 50 micrograms octreotide s.c. before the insulin withdrawal and every 3 h during insulin withdrawal. 3. Differences in integrated free fatty acid responses (4706 +/- 1227 mumol l-1 h vs 3026 +/- 835 mumol l-1 h, AUC, P = NS) were not significant, but the peak increments of acetoacetate (1413 +/- 354 mumol l-1 vs 612 +/- 176 mumol l-1, P less than 0.05), beta-hydroxybutyrate (2180 +/- 475 mumol l-1 vs 922 +/- 246 mumol l-1, P less than 0.01) and the decrements in plasma bicarbonate (-8 +/- 1 mumol l-1 vs -4 +/- 1 mumol l-1, P less than 0.05) and pH (-0.07 +/- 0.01 vs -0.03 +/- 0.01, P less than 0.05) were significantly less with octreotide. 4. At the same time peak increments of glucagon were lower with octreotide treatment (329 +/- 206 pg ml-1 vs 39 +/- 30 pg ml-1, P less than 0.05). 5. We conclude that, despite accelerated lipolysis and provision of substrate for ketogenesis during insulin withdrawal, this somatostatin analogue significantly reduces ketogenesis resulting from insulin deprivation, probably secondary to decreasing glucagon secretion. This drug may be useful in short term prophylactic treatment of diabetic patients during periods of increased risk for ketoacidosis.