57 zyxwvuts Atherosclerosis, 32 (1979) 57- 67 0 ElsevierlNorth-Holland Scientific Publishers, Ltd. TRIGLYCERIDE REMOVAL FROM VERY LOW DENSITY LIPOPROTEINS IN VIVO AS A FUNCTION OF THEIR TRIGLYCERIDE CONTENT D.A. STREJA Department of M edicine and Physiology, University of M anitoba, W innipeg, M anitoba (Canada) (Received 25 May, 1978) (Revised, received 5 September, 1978) (Accepted 7 September, 1978) Summary Rabbit very low density lipoproteins (VLDL) were fractionated in 3 subfrac- tions differing in density and triglyceride (TG) content. The fraction of total weight represented by triglycerides was: VLDLl TG = 71%, VLDLz TG = 62%, VLDL3 TG = 55%. No other difference in composition was observed. After intravenous administration of radioglycerol all subfractions were labelled and the distribution of radioactivity in their glycerolipids was the same. In 5 rabbits, a biologically labelled triglyceride-rich VLDLl subfraction preparation was administered and the specific activity of triglyceride was determined in all 3 subfractions in serial samples. A precursor-product relationship between VLDL1 TG and VLDL TG in other subfractions was not observed. In another set of experiments the disappearance rates of VLDL TG from subfractions were determined in recipient rabbits. The half-lives were: VLDL, TG = 9.5 + 1.3 min, VLDL? TG: 16.0 + 1.3 min, VLDL3 TG: 26.9 + 1.3 min. It is concluded that triglyceride removal from a VLDL subfraction varies inversely with its triglyceride content. A role for partial VLDL lipolysis in this metabolic heter- ogeneity was not established. Key words: Lipoprotein metabolism - Triglycerides - Very low density lipoprotein zyxwvutsrqpon This work was supported by grants from the Manitoba Heart Foundation and Banting Research Fund. The Author is a Medical Research Council Scholar. Correspondce and reprint requests to: D r. D.A. Streha, Health Sciences Centre. 700 William Avenue. W innipeg, M anitoba R3E 023, Canada.