Adipose tissue lipoprotein lipase (LPL) is a necessary enzyme for storage of VLDL-TG, but whether it is a rate determining step is unknown. fatty acid storage rate. LPL-activity, ATBF, and VLDL-TG turnover did not predict VLDL-TG storage. We conclude that lower FFM and greater plasma insulin is associated with greater VLDL-TG deposition in abdominal subcutaneous and femoral fat. Greater femoral fat mass signals greater femoral VLDL-TG storage. We suggest that the differences in VLDL-TG storage in abdominal and femoral fat that occur with progressive obesity are regulated through mechanisms other than LPL-activity. labeling of VLDL-TG followed by autolog re-infusion and adipose tissue biopsies to concurrently measure plasma VLDL-TG specific activity (SA) and regional fat storage(17). The primary objective was to assess the relationship between quantitative storage of VLDL-TG and LPL-activity in upper-body subcutaneous and femoral adipose tissue in UBO, LBO, and lean women. As a secondary objective we assessed the impact of fat cell size, body composition, VLDL-turnover, and adipose tissue blood flow on VLDL-TG storage and its relationship with LPL-activity. Methods and Procedures The study was approved by the local ethics committee and informed, written content was from all individuals. Twenty-nine healthful, premenopausal ladies (10 UBO, 11 LBO, and 8 low fat) who participated within an ongoing research of VLDL-TG rate of metabolism entered the analysis. The kinetic data has been published previously(18). The present manuscript describes aspects of adipocyte function. All participants had been recruited through newspaper advertisements. Upper and lower body obesity was defined as a BMI 28 kg/m2 in combination with a waist-to-hip ratio (WHR) 0.85 (UBO) or a WHR 0.8 (LBO). Lean subjects were defined as a BMI 25 kg/m2. All participants were normotensive, non-smokers, used no medication except oral contraceptives, and had a normal blood count and chemistry panel documented before participation. Subjects with a fasting plasma TG 2.3 mmol/l were not included. All were studied in the luteal phase. If there was uncertainty regarding their status as premenopausal (age 45 years), a blood sample was taken for determination of FSH and estradiol and subjects were excluded if FSH 10 IE/L and estradiol 0.5 mol/L. Two lean women had to be excluded because of incomplete data collection. Experimental protocol One week before the examination day a fasting 80 ml blood sample was obtained for VLDL-TG labeling as described beneath. Body composition and fat distribution were measured using dual-energy x-ray absorptiometry (DEXA) and abdominal computed tomography scanning. Weight maintaining meals (30% fat, 55% carbohydrate, 15% protein) were designed by a clinical dietician and provided from the hospital kitchen for 3 days before the study to assure consistent nutrient and energy intake. All volunteers maintained their usual level of physical activity and were asked not to participate in heavy exercise the last 3 days before the study. Throughout the examination day, the participants remained in bed wearing light hospital clothing in a room of ambient temperature of 22C24C. Participants were admitted to the research laboratory at 22. 00 h the day before the study. After an overnight fast two intravenous catheters were inserted – one in a dorsal hand vein and one in an P7C3-A20 cost antecubital vein. The hand was placed in a heated box for collection P7C3-A20 cost of arterialized blood. The obese volunteers got a solution of just one 1 MBq 133Xe (0.1 ml) injected subcutaneously in periumbilical and anterior femoral sites and a NaI P7C3-A20 cost detector was placed to measure activity washout during the day. Sadly, after having finished research in the obese ladies with only low fat subjects remaining, 131Xe was zero available through the provider longer. Thus, we had been forced to stop measurements of 131Xe washout in every the remaining low fat ladies. At 0800 h (period 0) baseline bloodstream samples were acquired and accompanied by an intravenous bolus infusion P7C3-A20 cost of 14C-labelled VLDL-TG over 5 min utilizing a calibrated pump. Bloodstream samples were attracted sometimes 0, 30, 60, 120, 180, 240, and 300 min, and analyzed for 14C-VLDL-TG focus and SA, FFA, and insulin. REE was assessed between 60C90 min by indirect calorimetry P7C3-A20 cost (Deltatrac monitor; Datex Instrumentarium, Helsinki, Finland). From 300C420 min a hyperinsulinemic euglycaemic clamp was performed. Insulin was infused for a price of 0.6 mU kg?1 min?1. Plasma blood sugar was assessed every 10 min IGF2R utilizing a Beckman analyzer (Beckmann Musical instruments, Palo Alto, California, USA) and clamped at ~5 mmol/L by infusion of blood sugar 20%. Blood sugar infusion price (M-value) was utilized as a way of measuring insulin sensitivity and also have been released previously(18). Four.