To assess the effect of glycemic control on triglyceride (TG) and apoprotein E (apo E) metabolism, plasma levels of TG and apo E were studied in nine nonobese subjects with insulin-dependent diabetes mellitus (IDDM) following acute ingestion of polyunsaturated fat. Each subject was studied twice: before and after ten days of continuous subcutaneous insulin infusion (CSII). Each subject ingested identical meals on both study days. Plasma glucose was determined in all patients before and two hours after each meal and at 3 am, and a mean value was calculated for each patient. CSII reduced mean plasma glucose from 205 to 113 mg/dL (P < .005, paired t test); there was no change in the total daily insulin dose. Plasma TG and apo E levels were measured before and 3.5, 5, and 7 hours after a breakfast which contained 50 g of fish oil (five subjects) or vegetable oil (four subjects). A repeated-measures ANOVA was performed to assess the effects of the following three factors on plasma TG and apoE levels: type of oil ingested (Oil, factor A), glycemic control (Glycemic control, factor B), and the response to fat ingestion over time (Times, factor C). Plasma levels of both apo E and TG increased significantly after fat ingestion (F test, ANOVA, P < .005 and P < .001, respectively). Glycemic control significantly reduced the rise in both apo E and TG levels (P < .005 and P < .05, respectively). The effect of the type of oil and the interactions tested (AB, AC, BC, ABC) were not statistically significant. A strong, statistically significant correlation was observed between plasma TG and apo E levels in both the fasting (r = .877, P < .005) and postprandial states (r = .675, P < .05) before CSII. Following glycemic control, this correlation persisted in the fasting but not in the postprandial state; moreover, the plasma postprandial TG/apo E ratio increased with CSII (P < .05), probably because the amount of apo E in the population of TG-rich lipoprotein particles (measured in three subjects) was reduced.
Bibliographical noteFunding Information:
From the Divisions of Endocrinology and Gerontology, Department of Medicine, The Johns Hopkins University, School of Medicine, Baltimore. Partially supported by US Public Health Service Grant RR-0003524 to the Clinical Research Center of the Johns Hopkins University School of Medicine. Address reprint requests to Angeliki Georgopoulos, MD, Division of Endocrinology, Department of Medicine, The Johns Hopkins University, School of Medicine, Traylor Research Building, Room 730. 720 Rutland Ave, Baltimore, IUD 21205. o 1988 by Grune & Stratton, Inc. 0026-0495/&q/3709-0007$03.00/0