Effect of insulin and sulfonylurea therapy, at the same level of blood glucose control, on low density lipoprotein subfractions in type 2 diabetic patients

The aim of this study was to evaluate the effect of sc insulin (INS) compar ed with sulfonylurea (SUL) therapy, at the same level of blood glucose cont rol, on the low density lipoprotein (LDL) subfraction profile in normolipid emic type 2 diabetic patients. Nine normolipidemic type 2 diabetic men (age , 56 +/- 3 yr; body mass index, 26.5 +/- 0.9 kg/m(2) mean +/- SEM), after a 3-week wash-out period, were assigned to INS or SUL for 2 months in a rand omized cross-over design. Doses were adjusted only during the first month a nd then were kept constant. At the end of the treatments, hemoglobin A(1c), plasma lipids, LDL, and very low density lipoprotein (VLDL) subfraction pr ofiles and plasma postheparin lipoprotein lipase and hepatic lipase (HL) ac tivities were evaluated. Despite glucose control was similar at the end of both periods (hemoglobin A(1c), 7.4 +/- 0.3% vs. 7.0 +/- 0.2%, INS vs. SUL) , INS compared with SUL significantly reduced plasma triglyceride (0.9 +/- 0.1 vs. 1.1 +/- 0.1 mmol/L; P < 0.05). Although INS did not affect the LDL concentration, it induced a decrease in both the amount (59.0 +/- 9.8 vs. 7 6.1 +/- 16.8 mg/dL; P = NS) and the proportion (31.2 +/- 3.0% vs. 38.3 +/- 3.8%; P < 0.03) of small LDL. Moreover, the decrease in small LDL was posit ively related to the reduction of large VLDL (r = 0.67; P < 0.04) and HL (r = 0.69, P < 0.05)induced by insulin therapy. In conclusion, sc insulin the rapy, independently even in the presence of quite low plasma triglyceride l evels, is able to reduce small LDL particles in type 2 diabetic patients. T his change is related to decreases in both HL activity and large VLDL parti cles.