The lipoprotein profile differs during insulin treatment alone and combination therapy with insulin and sulphonylureas in patients with Type 2 diabetes mellitus.

AIMS: To study whether changes in endogenous insulin secretion at the same glycaemic control affect the plasma concentrations of lipoproteins in patients with Type 2 diabetes mellitus. METHODS: Fifteen patients, age 59+/-2 years (mean +/- SEM), body weight 86.3+/-3.0kg, body mass index 29.6+/-0.9 kg/m2 were treated with sulphonylurea and insulin in combination or with insulin alone in a randomized, double-blind, crossover study. All patients were treated with a multiple daily injection regimen with the addition of glibenclamide 10.5 mg daily or placebo tablets. RESULTS: During combination therapy, the dose of insulin was 25% less (P < 0.002) and there was a 29% increase in plasma C-peptide concentration (P = 0.01). Plasma levels of free insulin were not changed. Plasma levels of sex hormone-binding globulin (SHBG) and insulin-like growth factor-binding protein (IGFBP)-1 were lowered. There were no differences in the 24-h blood glucose profiles or HbA1c (6.0+/-0.2 vs. 6.3+/-0.2%; P = 0.16). Body weight was similar. There was a significant decrease in plasma LDL cholesterol (3.04+/-0.24 vs. 3.41+/-0.21 mmol/l; P = 0.04), apolipoprotein A1 and of lipoprotein(a) but an increase in VLDL-triglycerides (1.36+/-0.31 vs. 0.96+/-0.16 mmol/l; P = 0.02) during combination therapy. The ratio between LDL cholesterol and apolipoprotein B concentrations was significantly lower during combination therapy (P < 0.01). CONCLUSIONS: Combination therapy with insulin and sulphonylureas increases portal insulin supply and thereby alters liver lipoprotein metabolism when compared with insulin therapy alone.

Inhibition of nisoldipine on bovine mesenteric arteries and veins and on human peripheral veins.

The inhibiting effect of the calcium channel blocker nisoldipine (CAS 63675-72-9, Baymycard, Syscor) on potassium-induced contraction on bovine mesenteric veins and arteries and human peripheral veins was investigated. Nisoldipine inhibited the contraction on bovine mesenteric veins at a significantly lower concentration (1 x 10(-10) mol/l) than nifedipine and glyceryl trinitrate (GTN) (1 x 10(-7) mol/l). When the preparations were preincubated with the drugs, nisoldipine reduced the contraction, measured as area under the curve (AUC), with 47 +/- 8% (mean +/- SEM) and nifedipine with 29 +/- 13% in veins. It was necessary to use an inconsiderably higher concentration of nisoldipine to relax bovine mesenteric arteries contracted by potassium. Preincubation of these arteries with nisoldipine (1 x 10(-7) mol/l) reduced contraction measured as AUC by 46 +/- 10% and preincubation with nifedipine (1 x 10(-7) mol/l) by 77 +/- 3%. Nisoldipine also caused a marked relaxation in human saphenous veins. The introduction of nisoldipine (1 x 10(-8) mol/l) after potassium-induced contraction caused 54 +/- 8% relaxation.

Nisoldipine--effects on the renin-angiotensin-aldosterone system and catecholamines. Studies in normotensive and hypertensive subjects.

We have studied the effects of nisoldipine, a new calcium channel antagonist, on the renin-angiotensin-aldosterone system and on plasma catecholamines in 10 healthy volunteers and in 29 patients with primary essential hypertension. Of these 29 patients, thirteen had normal renin hypertension (NRH), and sixteen had low renin hypertension (LRH). Eight healthy volunteers received placebo. Short-term (24 h) effects were measured in all subjects and long-term (up to 6 months) effects of 10-40 mg nisoldipine daily were monitored in the 29 hypertensive patients. Plasma renin activity (PRA) increased slightly, although this rise was not statistically significant, 1 h after the first dose of nisoldipine in both normotensive subjects and hypertensive patients. After 2 h PRA had returned to the pre-treatment level. No change in PRA was observed after administration of placebo. Plasma angiotensin II (AII) levels showed considerable variation after nisoldipine administration. Plasma aldosterone levels decreased despite the increase in PRA and AII concentrations. However, no concomitant reduction in urinary aldosterone excretion was observed. Plasma noradrenaline levels increased slightly 2-4 h after administration of nisoldipine, and decreased again thereafter, but no changes in plasma adrenaline levels were seen. Nisoldipine had no long-term effects on the renin-angiotensin-aldosterone system or on serum catecholamine levels.

Overnight metabolic control with bedtime injection of intermediate-acting insulin or continuous subcutaneous insulin infusion.

Ten insulin-dependent diabetic patients were investigated from 2100 to 0700 h during treatment with either a bedtime injection (BI) of intermediate-acting insulin or continuous subcutaneous insulin infusion (CSII) at a constant basal rate. In the evening, blood glucose was slightly higher during treatment with BI than with CSII, whereas the metabolic control in the morning was equal on both regimens with a fasting blood glucose of 5.7 mM (4.2-7.1) (median and interquartile ranges) on BI and 5.4 mM (4.6-5.8) on CSII (NS). No rise in morning blood glucose was seen, but serum beta-hydroxybutyrate tended to rise (NS). There was a significant hyperinsulinemia at midnight during BI compared with CSII with a serum free insulin of 14.5 (11.7-16.0) vs. 9.6 (7.2-11.2) mU/L (P less than .05), respectively, and the area under the curve during the middle of the night (midnight to 0400 h) was greater with BI than CSII (P less than .02). A greater fall in blood glucose was seen with BI than with CSII during this period (P less than .02). Differences in blood glucose and serum free-insulin profiles between those using NPH or lente insulin at bedtime were registered. We conclude that, although the same metabolic control in the morning was achievable with CSII at a constant basal rate and BI, CSII is superior for overnight metabolic control due to less-pronounced hyperinsulinemia during the night and a steady-state level of free insulin in the morning.