To the Editor: In their article on the use of an implantable pump (July 29 issue),1 Rupp et al. demonstrated that normal triglyceride values could be further reduced by means of intravenous insulin infusion in nonobese patients with Type II diabetes. Several groups of workers2 3 4 have already reported that subcutaneous insulin infusion restores triglyceride concentrations to normal in Type I diabetics. The presumed mechanism for this reduction is the stimulation of lipoprotein lipase activity, which is deficient during insulin deprivation, resulting in the enhanced clearance of triglyceride-rich particles.5 The hypertriglyceridemia commonly observed in obese Type II diabetics is related to. . .