Effect of an anti-lipoprotein lipase serum on plasma triglyceride removal.

Anti-lipoprotein lipase sera injected intravenously in roosters blocked quantitatively the catabolism of very low density lipoprotein (VLDL) triglyceride. Antibodies were produced in rabbits immunized with highly purified lipoprotein lipase (LPL, glycerol ester hydrolase, E C 3.1.1.3) prepared from chicken adipose tissue. Following anti-LPL serum injection there was a linear increase in plasma triglyceride concentration. The rate of entry of triglyceride in plasma was estimated from the rate of triglyceride accumulation in the plasma of animals injected with anti-LPL serum, or from the disappearance curve of biologically labelled VLDL. In instances where both measurements were conducted in the same animals there was very close agreement between the two procedures. Inhibition of VLDL triglyceride catabolism of anti-LPL serum provided a way to characterize newly secreted VLDL that exhibited a broad spectrum of particle sizes with a median of 625 A degrees. They contained 76.2 +/- 1.2% triglyceride and had a high ratio of free to ester cholesterol (2.46 +/- 0.45). In control VLDL samples there was 46.1% triglyceride, and the ratio of free to ester cholesterol was 1.19. The complete inhibition of triglyceride removal by an antiserum prepared against adipose tissue LPL demonstrates that the NaCl-inhibited, serum-activated lipase prepared by affinity chromatography on heparin-Sepharose and concanavalin A-Sepharose columns is the enzyme responsible in vivo for the catabolism of VLDL triglyceride. Further, the kinetics of triglyceride accumulation in the plasma provide evidence that the site of degradation of VLDL triglyceride is within the plasma compartment.     

Studies on the mechanism of hypertriglyceridemia in the genetically obese Zucker rat

The possibility that impaired removal of lipoprotein triglyceride from the circulation may be a participating factor in the hypertriglyceridemia of the obese Zucker rat was examined. We found no significant differences in the heparin-released lipoprotein lipase (LPL) activities of the adipose tissue, skeletal muscle, and heart (expressed per gram of tissue) from the lean and obese Zucker rats. Furthermore, the kinetic properties of adipose tissue and heart LPL from the lean and obese rats were similar, indicating that the catalytic efficiency of the enzyme was unaltered in the obese animals. The postheparin plasma LPL activities of lean and obese rats were also similar. However, the postheparin plasma hepatic triglyceride lipase (H-TGL) activity in the obese rats was elevated. The higher activity of H-TGL could not alleviate the hypertriglyceridemia in these animals. Since hypertriglyceridemia in the obese rats could also be due to the hepatic production of triglyceride-rich lipoproteins which are resistant to lipolysis, we therefore isolated very low density lipoproteins (VLDL) from lean and obese rat liver perfusates and examined their degradation by highly purified human milk LPL. Although certain differences were observed in hepatic VLDL triglyceride fatty acid composition, the kinetic patterns of LPL-catalyzed triglyceride disappearance from lean and obese rat liver perfusate VLDL were similar. The isolated liver perfusate VLDL contained sufficient apolipoprotein C-II for maximum lipolysis. These results indicate that impaired lipolysis is not a contributing factor in the genesis of hypertriglyceridemia in the genetically obese Zucker rat. The hyperlipemic state may be attributed to hypersecretion of hepatic VLDL and consequent saturation of the lipolytic removal of triglyceride-rich lipoproteins from the circulation.     

Tamoxifen inhibits lipoprotein activity: in vivo and in vitro studies

Tamoxifen, a nonsteroidal antiestrogenic antitumor agent, has weak estrogen-like effects on lipid metabolism, however, the mechanism remains unknown. We previously reported that tamoxifen decreases the activity of lipoprotein lipase (LPL), a key enzyme in triglyceride metabolism, in patients with breast cancer. This study evaluated the effect of tamoxifen on LPL activity in vitro and in vivo. In experiment 1, total cholesterol, triglyceride, adipose tissue weight, and LPL activity of post-heparin plasma were measured in ovariectomized female rats with and without tamoxifen treatment. In experiment 2, purified very-low-density lipoprotein (VLDL) and purified LPL were incubated with and without tamoxifen or estrogen, and the triglycerides in VLDL were measured using an enzymatic method. In experiment 1, total cholesterol and adipose tissue weight decreased significantly in tamoxifen-treated rats (p < 0.001 and p < 0.01, respectively). Triglyceride measurements were not significantly different between the two groups, however, the LPL activity was lower in tamoxifen-treated rats (p < 0.005). In experiment 2, triglycerides in VLDL were significantly higher after VLDL and LPL were incubated with tamoxifen and estrogen (p < 0.005). We concluded that tamoxifen inhibits the hydrolytic activity of LPL in vivo and in vitro. This mechanism may explain the elevated serum triglyceride levels in some patients treated with tamoxifen.     

Overexpression of human apolipoprotein A-II in mice induces hypertriglyceridemia due to defective very low density lipoprotein hydrolysis

Two lines of transgenic mice, hAIItg-delta and hAIItg-lambda, expressing human apolipoprotein (apo)A-II at 2 and 4 times the normal concentration, respectively, displayed on standard chow postprandial chylomicronemia, large quantities of very low density lipoprotein (VLDL) and low density lipoprotein (LDL) but greatly reduced high density lipoprotein (HDL). Hypertriglyceridemia may result from increased VLDL production, decreased VLDL catabolism, or both. Post-Triton VLDL production was comparable in transgenic and control mice. Postheparin lipoprotein lipase (LPL) and hepatic lipase activities decreased at most by 30% in transgenic mice, whereas adipose tissue and muscle LPL activities were unaffected, indicating normal LPL synthesis. However, VLDL-triglyceride hydrolysis by exogenous LPL was considerably slower in transgenic compared with control mice, with the apparent Vmax of the reaction decreasing proportionately to human apoA-II expression. Human apoA-II was present in appreciable amounts in the VLDL of transgenic mice, which also carried apoC-II. The addition of purified apoA-II in postheparin plasma from control mice induced a dose-dependent decrease in LPL and hepatic lipase activities. In conclusion, overexpression of human apoA-II in transgenic mice induced the proatherogenic lipoprotein profile of low plasma HDL and postprandial hypertriglyceridemia because of decreased VLDL catabolism by LPL.     

The very low density lipoprotein (VLDL) receptor – a peripheral lipoprotein receptor for remnant lipoproteins into fatty acid active tissues

The VLDL (very low density lipoprotein) receptor is a member of the LDL (low density lipoprotein) receptor family. The VLDL receptor binds apolipoprotein (apo) E but not apo B, and is expressed in fatty acid active tissues (heart, muscle, adipose) and macrophages abundantly. Lipoprotein lipase (LPL) modulates the binding of triglyceride (TG)-rich lipoprotein particles to the VLDL receptor. By the unique ligand specificity, VLDL receptor practically appeared to function as IDL (intermediate density lipoprotein) and chylomicron remnant receptor in peripheral tissues in concert with LPL. In contrast to LDL receptor, the VLDL receptor expression is not down regulated by lipoproteins. Recently several possible functions of the VLDL receptor have been reported in lipoprotein metabolism, atherosclerosis, obesity/insulin resistance, cardiac fatty acid metabolism and neuronal migration. The gene therapy of VLDL receptor into the LDL receptor knockout mice liver showed a benefit effect for lipoprotein metabolism and atherosclerosis. Further researches about the VLDL receptor function will be needed in the future.     

Apolipoprotein AV accelerates plasma hydrolysis of triglyceride-rich lipoproteins by interaction with proteoglycan-bound lipoprotein lipase

Apolipoprotein A5 (APOA5) is associated with differences in triglyceride levels and familial combined hyperlipidemia. In genetically engineered mice, apoAV plasma levels are inversely correlated with plasma triglycerides. To elucidate the mechanism by which apoAV influences plasma triglycerides, metabolic studies and in vitro assays resembling physiological conditions were performed. In human APOA5 transgenic mice (hAPOA5tr), catabolism of chylomicrons and very low density lipoprotein (VLDL) was accelerated due to a faster plasma hydrolysis of triglycerides by lipoprotein lipase (LPL). Hepatic VLDL and intestinal chylomicron production were not affected. The functional interplay between apoAV and LPL was further investigated by cross-breeding a human LPL transgene with the apoa5 knock-out and the hAPOA5tr to an lpl-deficient background. Increased LPL activity completely normalized hypertriglyceridemia of apoa5-deficient mice; however, overexpression of human apoAV modulated triglyceride levels only slightly when LPL was reduced. To reflect the physiological situation in which LPL is bound to cell surface proteoglycans, we examined hydrolysis in the presence or absence of proteoglycans. Without proteoglycans, apoAV derived either from triglyceride-rich lipoproteins, hAPOA5tr high density lipoprotein, or a recombinant source did not alter the LPL hydrolysis rate. In the presence of proteoglycans, however, apoAV led to a significant and dose-dependent increase in LPL-mediated hydrolysis of VLDL triglycerides. These results were confirmed in cell culture using a proteoglycan-deficient cell line. A direct interaction between LPL and apoAV was found by ligand blotting. It is proposed, that apoAV reduces triglyceride levels by guiding VLDL and chylomicrons to proteoglycan-bound LPL for lipolysis.     

Metabolism of VLDL is increased in streptozotocin-induced diabetic rat hearts

In streptozotocin (STZ)-induced diabetic rats, we previously showed an increased heparin-releasable (luminal) lipoprotein lipase (LPL) activity from perfused hearts. To study the effect of this enlarged LPL pool on triglyceride (TG)-rich lipoproteins, we examined the metabolism of very-low-density lipoprotein (VLDL) perfused through control and diabetic hearts. Diabetic rats had elevated TG levels compared with control. However, fasting for 16 h abolished this difference. When the plasma lipoprotein fraction of density <1.006 g/ml from fasted control and diabetic rats was incubated in vitro with purified bovine or rat LPL, VLDL from diabetic animals was hydrolyzed as proficiently as VLDL from control animals. Post-heparin plasma lipolytic activity was comparable in control and diabetic animals. However, perfusion of control and diabetic rats with heparinase indicated that diabetic hearts had larger amounts of LPL bound to heparan sulfate proteoglycan-binding sites. [(3)H]VLDL obtained from control rats, when recirculated through the isolated heart, disappeared at a significantly faster rate from diabetic than from control rat hearts. This increased VLDL-TG hydrolysis was essentially abolished by prior perfusion of the diabetic heart with heparin, implicating LPL in this process. These findings suggest that the enlarged LPL pool in the diabetic heart is present at a functionally relevant location (at the capillary lumen) and is capable of hydrolyzing VLDL. This could increase the delivery of free fatty acid to the heart, and the resultant metabolic changes could induce the subsequent cardiomyopathy that is observed in the chronic diabetic rat.     

脂蛋白酯酶与动脉粥样硬化

脂蛋白酯酶(1ipopmtein lipase,LPL)是调节脂蛋白代谢的一种关键酶,如具有水解血浆脂蛋白中三酰甘油的作用等．体内LPL减少会导致血三酰甘油升高和高密度脂蛋白胆固醇降低,增加患动脉粥样硬化的危险．通过提高LPL的活性可以抑制动脉粥样硬化的发生发展．已有的研究说明NO-1886促进心肌和脂肪组织LPL mRNA表达,提高心肌、脂肪组织、骨骼肌和血液中LPL活性,因而改善脂蛋白代谢,抑制动脉粥样硬化．     

Role of lipoprotein lipase separated from VLDL during VLDL catabolism

Lipoprotein lipase (LPL) which is associated with very low density lipoprotein (VLDL) separated from the VLDL-LPL complex during hydrolysis of triglyceride in the presence of HDL in vitro. When further VLDL was added to the mixture, the separated LPL became associated with the freshly added VLDL and hydrolyzed its triglyceride. These results suggest that LPL separated from the substrate during catabolism of VLDL may act on other VLDL particles in vivo.     

Plasma lipoprotein metabolism in lean and in fat chickens produced by divergent selection for plasma very low density lipoprotein concentration

Plasma lipoprotein metabolism was studied in vivo in two lines of chickens produced by selection for high and low plasma very low density lipoprotein (VLDL) concentration. Rates of VLDL secretion were measured by determining the rate of accumulation of triglyceride in the plasma after intravenous injection of anti-lipoprotein lipase antibody. The clearance of VLDL-triglyceride and its uptake into liver and adipose tissue was examined using radioactively labeled VLDL synthesized in vivo. The rate of VLDL secretion was about threefold higher in the high-VLDL line as compared to the leaner, low VLDL-line (6.7 vs 2.1 mumol VLDL triglyceride/h per ml of plasma). The clearance of VLDL from the circulation of the low VLDL line was much faster than that of the high VLDL line (t1/2 of 3.7 and 13.6 min, respectively). The proportion of administered radiolabel taken up by the abdominal fat pad was substantially greater in the fat line than in the lean line (11.9 vs 4.8%, respectively). Lipoprotein lipase activities in leg muscle and heart were consistently greater in the low-VLDL line and beta-hydroxybutyrate concentrations in the plasma of the low-VLDL line were significantly greater than those in the high-VLDL line (0.86 vs 0.48 mumol/ml). The results show that the approximately tenfold difference in plasma VLDL concentration between lines is primarily due to markedly different rates of hepatic VLDL production and that selection has made a major effect on partitioning of VLDL triglyceride between adipose and other tissues.(ABSTRACT TRUNCATED AT 250 WORDS)     

Modifications of plasma lipoproteins after lipase activation in patients with chylomicronemia

Lipoprotein lipase (LPL) and hepatic lipase (HL) are enzymatic activities involved in lipoprotein metabolism. The purpose of this study was to analyze the physicochemical modifications of plasma lipoproteins produced by LPL activation in two patients with apoC-II deficiency syndrome and by HL activation in two patients with LPL deficiency. LPL activation was achieved by the infusion of normal plasma containing apoC-II and HL was released by the injection of heparin. Lipoproteins were analyzed by ultracentrifugation in a zonal rotor under rate flotation conditions before and after lipase activation. The LPL activation resulted in: a reduction of plasma triglycerides; a reduction of fast-floating very low density lipoprotein (VLDL) concentration; an increase of intermediate density lipoprotein (IDL), which maintained unaltered flotation properties; an increase of low density lipoproteins (LDL) accompanied by modifications of their flotation rates and composition; no significant variations of high density lipoprotein (HDL) levels; and an increase of the HDL flotation rate. The HL activation resulted in: a slight reduction of plasma triglycerides; a reduction of the relative triglyceride content of slow-floating VLDL, IDL, LDL2, and HDL3 accompanied by an increase of phospholipid in VLDL and by an increase of cholesteryl ester in IDL; and a reduction of the HDL flotation rate. These experiments in chylomicronemic patients provide in vivo evidence that LPL and HL are responsible for plasma triglyceride hydrolysis of different lipoproteins, and that LPL is particularly involved in determining the levels and physicochemical properties of LDL. Moreover, in these patients, the LPL activation does not directly change the HDL levels, and LPL or HL does not produce a step-wise conversion of HDL3 to HDL2 (or vice versa) but rather modifies the flotation rates of all the HDL molecules present in plasma.     

The acute phase response stimulates the expression of angiopoietin like protein 4

The acute phase response is characterized by elevations in serum triglyceride levels due to both an increase in hepatic VLDL production and a delay in the clearance of triglyceride rich lipoproteins secondary to a decrease in lipoprotein lipase (LPL) activity. Recently there has been a marked increase in our understanding of factors that regulate LPL activity. GPIHBP1 facilitates the interaction of LPL and lipoproteins thereby allowing lipolysis to occur. Angiopoietin like proteins (ANGPTL) 3 and 4 inhibit LPL activity. In the present study, treatment of mice with LPS, an activator of TLR4 and a model of Gram-negative infections, did not alter the expression of GPIHBP1 in heart or adipose tissue. However, LPS decreased the expression of ANGPTL3 in liver and increased the expression of ANGPTL4 in heart, muscle, and adipose tissue. Serum ANGPTL4 protein levels were markedly increased at 8 and 16 h following LPS treatment. Administration of zymosan, an activator of TLR2 and a model of fungal infections, also increased serum ANGPTL4 protein and mRNA levels in liver, heart, muscle, and adipose tissue. Finally, treatment of 3T3-L1 adipocytes with LPS or cytokines (TNF alpha, IL-1 beta, and interferon gamma) stimulated ANGPTL4 expression. These studies demonstrate that ANGPTL4 is a positive acute phase protein and the increase in ANGPTL4 could contribute to the hypertriglyceridemia that characteristically occurs during the acute phase response by inhibiting LPL activity.     

Lipid metabolism in endotoxic rats: decrease in hepatic triglyceride lipase activity

Studies were conducted to investigate the effect of E. coli endotoxin administration on hepatic triglyceride lipase (H-TGL) activity in rats, since H-TGL activity is known to behave differently from lipoprotein lipase (LPL) activity in various situations. Plasma triglyceride and free fatty acid concentrations were markedly elevated in animals after injection of endotoxin. Cholesterol and phospholipids were also increased significantly. Lipoprotein analysis by ultracentrifugation showed that the most pronounced increase of lipoproteins was in the VLDL and IDL fractions. Triglyceride lipase activities in post-heparin plasma were markedly decreased. A selective assay for H-TGL activity using a specific antibody revealed that this enzyme as well as LPL is significantly decreased (26% of control) in endotoxic animals. Thus, the increase of VLDL and IDL appears to result from the decrease of both of LPL and H-TGL.     

Comparative studies of vertebrate lipoprotein lipase: a key enzyme of very low density lipoprotein metabolism

Lipoprotein lipase (LIPL or LPL; E.C.3.1.1.34) serves a dual function as a triglyceride lipase of circulating chylomicrons and very-low-density lipoproteins (VLDL) and facilitates receptor-mediated lipoprotein uptake into heart, muscle and adipose tissue. Comparative LPL amino acid sequences and protein structures and LPL gene locations were examined using data from several vertebrate genome projects. Mammalian LPL genes usually contained 9 coding exons on the positive strand. Vertebrate LPL sequences shared 58-99% identity as compared with 33-49% sequence identities with other vascular triglyceride lipases, hepatic lipase (HL) and endothelial lipase (EL). Two human LPL N-glycosylation sites were conserved among seven predicted sites for the vertebrate LPL sequences examined. Sequence alignments, key amino acid residues and conserved predicted secondary and tertiary structures were also studied. A CpG island was identified within the 5'-untranslated region of the human LPL gene which may contribute to the higher than average (×4.5 times) level of expression reported. Phylogenetic analyses examined the relationships and potential evolutionary origins of vertebrate lipase genes, LPL, LIPG (encoding EL) and LIPC (encoding HL) which suggested that these have been derived from gene duplication events of an ancestral neutral lipase gene, prior to the appearance of fish during vertebrate evolution. Comparative divergence rates for these vertebrate sequences indicated that LPL is evolving more slowly (2-3 times) than for LIPC and LIPG genes and proteins.     

Lipoprotein lipase deficiency and CETP in streptozotocin-treated apoB-expressing mice

Both hyperglycemia and hyperlipidemia have been postulated to increase atherosclerosis in patients with diabetes mellitus. To study the effects of diabetes on lipoprotein profiles and atherosclerosis in a rodent model, we crossed mice that express human apolipoprotein B (HuB), mice that have a heterozygous deletion of lipoprotein lipase (LPL1), and transgenic mice expressing human cholesteryl ester transfer protein (CETP). Lipoprotein profiles due to each genetic modification were assessed while mice were consuming a Western type diet. Fast-protein liquid chromatography analysis of plasma samples showed that HuB/LPL1 mice had increased VLDL triglyceride, and HuB/LPL1/CETP mice had decreased HDL and increased VLDL and IDL/LDL. All strains of mice were made diabetic using streptozotocin (STZ); diabetes did not alter lipid profiles or atherosclerosis in HuB or HuB/LPL1/CETP mice. In contrast, STZ-treated HuB/LPL1 mice were more diabetic, severely hyperlipidemic due to increased cholesterol and triglyceride in VLDL and IDL/LDL, and had more atherosclerosis.     

Hormone-sensitive lipase deficiency in mice changes the plasma lipid profile by affecting the tissue-specific expression pattern of lipoprotein lipase in adipose tissue and muscle.

Hormone-sensitive lipase (HSL) is believed to play an important role in the mobilization of fatty acids from triglycerides (TG), diglycerides, and cholesteryl esters in various tissues. Because HSL-mediated lipolysis of TG in adipose tissue (AT) directly feeds non-esterified fatty acids (NEFA) into the vascular system, the enzyme is expected to affect many metabolic processes including the metabolism of plasma lipids and lipoproteins. In the present study we examined these metabolic changes in induced mutant mouse lines that lack HSL expression (HSL-ko mice). During fasting, when HSL is normally strongly induced in AT, HSL-ko animals exhibited markedly decreased plasma concentrations of NEFA (-40%) and TG (-63%), whereas total cholesterol and HDL cholesterol levels were increased (+34%). Except for the increased HDL cholesterol concentrations, these differences were not observed in fed animals, in which HSL activity is generally low. Decreased plasma TG levels in fasted HSL-ko mice were mainly caused by decreased hepatic very low density lipid lipoprotein (VLDL) synthesis as a result of decreased NEFA transport from the periphery to the liver. Reduced NEFA transport was also indicated by a depletion of hepatic TG stores (-90%) and strongly decreased ketone body concentrations in plasma (-80%). Decreased plasma NEFA and TG levels in fasted HSL-ko mice were associated with increased fractional catabolic rates of VLDL-TG and an induction of the tissue-specific lipoprotein lipase (LPL) activity in cardiac muscle, skeletal muscle, and white AT. In brown AT, LPL activity was decreased. Both increased VLDL fractional catabolic rates and increased LPL activity in muscle were unable to provide the heart with sufficient NEFA, which led to decreased tissue TG levels in cardiac muscle. Our results demonstrate that HSL deficiency markedly affects the metabolism of TG-rich lipoproteins by the coordinate down-regulation of VLDL synthesis and up-regulation of LPL in muscle and white adipose tissue. These changes result in an "anti-atherogenic" lipoprotein profile.     

Lipoprotein lipase of ovarian follicles in the domestic chicken (Gallus domesticus) (38537).

A lipase, bearing the characteristics of adipose tissue lipoprotein lipase (LPL) has been characterized in avian ovarian granulosa cells. The activity is low in cells from follicles weighing less than 0.5 g; in heavier follicles which have entered the rapid growth phase, significant activity (1 mumole fatty acid/mg protein/hr) could be identified. Granulosa LPL provides follicular tissues with the requisite enzyme system to hydrolyze very low density lipoprotein triglyceride en route to the oocyte.     

Oral nicotine induces an atherogenic lipoprotein profile

Male squirrel monkeys were used to evaluate the effect of chronic oral nicotine intake on lipoprotein composition and metabolism. Eighteen yearling monkeys were divided into two groups: 1) Controls fed isocaloric liquid diet; and 2) Nicotine primates given liquid diet supplemented with nicotine at 6 mg/kg body wt/day. Animals were weighed biweekly, plasma lipid, glucose, and lipoprotein parameters were measured monthly, and detailed lipoprotein composition, along with postheparin plasma lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) activity, was assessed after 24 months of treatment. Although nicotine had no effect on plasma triglyceride or high density lipoproteins (HDL), the alkaloid caused a significant increase in plasma glucose, cholesterol, and low density lipoprotein (LDL) cholesterol plus protein while simultaneously reducing the HDL cholesterol/plasma cholesterol ratio and animal body weight. Levels of LDL precursors, very low density (VLDL) and intermediate density (IDL) lipoproteins, were also lower in nicotine-treated primates while total postheparin lipase (LPL + HTGL) activity was significantly elevated. Our data indicate that long-term consumption of oral nicotine induces an atherogenic lipoprotein profile (increases LDL, decreases HDL/total cholesterol ratio) by enhancing lipolytic conversion of VLDL to LDL. These results have important health implications for humans who use smokeless tobacco products or chew nicotine gum for prolonged periods.     

Postabsorptive VLDL‐TG Fatty Acid Storage in Adipose Tissue in Lean and Obese Women

Adipose tissue lipoprotein lipase (LPL) is a necessary enzyme for storage of very‐low‐density lipoprotein–triglyceride (VLDL‐TG), but whether it is a rate‐determining step is unknown. To test this hypothesis we included 10 upper‐body obese (UBO), 11 lower‐body obese (LBO), and 8 lean women. We infused ex vivo‐labeled VLDL‐¹⁴C‐TG and then performed adipose tissue biopsies to understand the relationship between VLDL‐TG storage and LPL activity in femoral and upper‐body subcutaneous fat. Both fractional tracer storage and rate of storage of the VLDL‐TG tracer were evaluated. VLDL‐TG storage was also examined as a function of regional adipose tissue blood flow (ATBF), insulin, VLDL‐TG turnover, regional fat mass, fat‐free mass (FFM), and fat cell size. LPL activity per adipocyte was significantly greater in obese than lean women but not significantly different per gram lipid. Both VLDL‐TG fractional tracer storage per kg lipid and VLDL‐TG storage rate per kg lipid were similar in abdominal and femoral fat in all three groups and were not significantly different between groups. Multiple regression analysis identified FFM and femoral fat mass as significant independent predictors of VLDL‐TG fractional tracer storage and insulin as a significant predictor of VLDL‐TG 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 are 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.