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A novel method for measurement of omental fat contribution to VLDL‐triglyceride synthesis in human subjects
Author(s) -
Børsheim Elisabet,
Katsanos Christos,
Chinkes David L.,
Wolfe Robert R.,
Aarsland Asle
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a456
Subject(s) - very low density lipoprotein , triglyceride , medicine , endocrinology , chemistry , adipose tissue , lipoprotein , cholesterol
Central obesity with omental fat accumulation is linked to insulin resistance and the metabolic syndrome. The omental fat tissue may be a substantial source of fatty acids (FA) for hepatic uptake and further release as VLDL‐triglycerides (TG), but this has not been quantified in humans because of lack of methodology. The aim of this study was to quantify the contribution of omental fat to VLDL‐TG synthesis in healthy subjects. Six men (26±6(SD) yr; 179±6 cm; 74±10 kg) each participated in a 24 h study with infusion of 13 C‐acetate and U‐ 13 C‐palmitate, combined with blood samples. Total fractional secretion rate (FSR) of VLDL‐TG and FSR of FA originally taken up from the systemic circulation in VLDL‐TG (FA‐S) were calculated from the palmitate tracer. FSR of de novo synthesized FA in VLDL‐TG (FA‐dn) was calculated from the acetate tracer. FSR of FA originating from omental fat in VLDL‐TG (FA‐O) was calculated as FSR of total VLDL‐TG minus FSR (FA‐dn + FA‐S). The FSRs (%/h) were as follows: total VLDL: 21.9±1.9(SE); FA‐S: 15.4±1.2; FA‐dn: 0.6±0.1; and FA‐O: 5.9±1.9. Percentage contribution from FA‐O to total VLDL‐TG was 25±9 %. Thus, the omental fat tissue contributed significantly to the VLDL‐TG [t‐test, FSR of total VLDL‐TG vs FSR (FA‐dn + FA‐S): p = 0.03]. In conclusion, the lipolytic activity of the omental tissue in human subjects can be measured by this novel method using stable isotopes.