The activities of lipoprotein lipase and of enzymes involved in triacylglycerol synthesis in rat adipose tissue. Effects of starvation, dietary modification and of corticotropin injection.

1. The effects of dietary modification, including starvation, and of corticotropin injection on the activities of acyl-CoA synthetase, glycerol phosphate acyltransferase, dihydroxyacetone phosphate acyltransferase, phosphatidate phosphohydrolase, diacylglycerol acyltransferase and lipoprotein lipase were measured in adipose tissue. 2. Lipoprotein lipase activities in heart were increased and those in adipose tissue were decreased when rats were fed on diets enriched with corn oil or beef tallow rather than with sucrose or starch. The lipoprotein lipase activity was lower in the adipose tissue of rats fed on the sucrose rather than on the starch diet. 3. Rats fed on the beef tallow diet had slightly higher activities of the total glycerol phosphate acyltransferase in adipose tissue than did rats fed on the sucrose or starch diet. The diacylglycerol acyltransferase and the mitochondrial glycerol phosphate acyltransferase activities were higher for the rats fed on the tallow diet than for those fed on the corn-oil diet. 4. Starvation significantly decreased the activities of lipoprotein lipase (after 24 and 48 h), acyl-CoA synthetase (after 24 h) and of the mitochondrial glycerol phosphate acyltransferase and the N-ethylmaleimide-insensitive dihydroxyacetone phosphate acyltransferase (after 48 h) in adipose tissue. The activities of the microsomal glycerol phosphate acyltransferase, diacylglycerol acyltransferase and the soluble phosphatidate phosphohydrolase were not significantly changed after 24 or 48 h of starvation. 5. The activities of lipoprotein lipase and phosphatidate phosphohydrolase in adipose tissue were decreased 15 min after corticotropin was injected into rats during November to December. No statistically significant differences were found when these experiments were performed during March to September. These differences may be related to the seasonal variation in acute lipolytic responses. 6. These results are discussed in relation to the control of triacylglycerol synthesis and lipoprotein metabolism.     

有氧运动同时补充玉米肽对肥胖大鼠脂肪分解关键酶的影响

目的：研究有氧运动同时补充玉米肽对高脂饮食诱导的肥胖大鼠减脂的作用及其与脂肪分解关键酶甘油三酯脂肪酶（ATGL）和脂蛋白酯酶（LPL）关系。方法：4周龄健康雄性SD大鼠150只,体重160~180 g,随机选取15只作为普通膳食不运动组,给予普通饲料喂养。剩余135只大鼠进行8周的高脂饲料喂养建立肥胖大鼠模型,以体重超过普通膳食不运动组大鼠平均体重的20%作为肥胖大鼠建模成功的标准。将建模成功的肥胖大鼠40只随机分为5组（n=8）：肥胖对照组、酪蛋白组、玉米肽组、运动组和运动+玉米肽组。除酪蛋白组、玉米肽组喂养自制饲料外,其余各组均用普通饲料喂养,运动组每天进行15 m/min,持续时间60 min的跑台运动,每周6天。4周运动和玉米肽干预后取血,检测大鼠血浆中TG、TC、HDL、LDL的含量;取大鼠肾周、附睾脂肪和肝,检测肾周和附睾脂肪的重量,Western blot检测大鼠肝ATGL、脂肪LPL的蛋白表达水平。结果：与肥胖对照组大鼠相比：①运动组、运动+玉米肽组大鼠的体重、附睾和肾周脂肪含量明显降低（P<0.05）,且运动+玉米肽组比运动组下降得更明显（P<0.05）,而其它组大鼠无显著差异。②运动组大鼠血浆TG显著降低,运动+玉米肽组的血浆TG、TC显著降低（P<0.05）,其它组大鼠的TG、TC无显著差异;血浆HDL和LDL各组间均无显著性差异。③运动组和运动+玉米肽组大鼠的肝ATGL、脂肪组织LPL的蛋白水平明显增加（P<0.01）,且运动+玉米肽组比运动组的更显著（P<0.05）;其他两组无显著差异。结论：有氧运动、有氧运动同时补充玉米肽都可以明显降低大鼠的体脂和血脂水平,且后者的作用更强,这可能与其更显著地增加肥胖大鼠肝ATGL和脂肪LPL的蛋白水平有关。而仅仅补充玉米肽不能降低大鼠的体脂和血脂水平。     

Zinc deficiency and the activities of lipoprotein lipase in plasma and tissues of rats force-fed diets with coconut oil or fish oil

The present study was performed to investigate the effect of zinc deficiency on the activities of lipoprotein lipase in postheparin serum and tissues of rats fed diets containing either coconut oil or fish oil as dietary fat, using a bifactorial experimental design. To ensure an adequate food intake, all the rats were force-fed by gastric tube. Experimental diets contained either 0.8 mg zinc/kg (zinc-deficient diets) or 40 mg zinc/kg (zinc-adequate diets). The effects of zinc deficiency on the activities of lipoprotein lipase in postheparin serum and postprandial triglyceride concentrations and distribution of apolipoproteins in serum lipoproteins depended on the type of dietary fat. Zinc-deficient rats fed the coconut oil diet exhibited a reduced activity of lipoprotein lipase in postheparin serum and adipose tissue, markedly increased concentrations of triglycerides in serum, and a markedly reduced content of apolipoprotein C in triglyceride-rich lipoproteins and high density lipoproteins compared with zinc-adequate rats fed coconut oil. By contrast, zinc-deficient rats fed the fish oil diet did not exhibit reduced activities of lipoprotein lipase in postheparin serum and adipose tissue and increased concentrations of serum lipids compared with zinc-adequate rats fed the fish oil diet. This study suggests that a reduced activity of lipoprotein lipase might contribute to increased postprandial concentrations of serum triglycerides observed in zinc-deficient animals. However, it also demonstrates that the effects of zinc deficiency on lipoprotein metabolism are influenced by dietary fatty acids.     

Effect of dietary carbohydrate type on lipoprotein lipase, hepatic lipase, and lecithin:cholesterol acyltransferase activities in cynomolgus monkeys

The effects of dietary sucrose and starch with and without exogenous cholesterol on postheparin plasma lipoprotein lipase (PHLA) and hepatic lipase (HLA) were studied in cynomolgus monkeys. Serum triglyceride levels were higher in sucrose-fed animals than starch and exogenous cholesterol lowered serum triglyceride levels when added to sucrose diet but not starch diets. Sucrose markedly increased insulin levels, more so than starch; however, dietary cholesterol lowered insulin levels in sucrose diet but increased the levels in starch diet. PHLA activity was increased two- to threefold greater in sucrose than in starch diets. Exogenous cholesterol lowered PHLA activity in sucrose diet but increased PHLA activity in starch diet. HLA activity was increased with sucrose more than starch. Lecithin:cholesterol acyltransferase (LCAT) activity was significantly higher in sucrose diets than in the starch diet. Addition of cholesterol to either of these diets lowered the LCAT activity. These results indicate that PHLA, HLA, and LCAT activities not only are affected by the nature of carbohydrates, but also are related to triglyceride metabolism. The interaction of carbohydrates and cholesterol in the diet by influencing these selected enzymes plays an integrated role in lipoprotein particle interconversion processes.     

Effect of dietary palm oil on lipoprotein lipases: lipoprotein levels and tissue lipids in rat

The aims of our study were to investigate the effect of dietary palm oil on the levels of lipoprotein lipase, hepatic lipase, fat distribution (in the aorta and liver), and total cholesterol, HDL, LDL, and triacylglycerol levels in young rats (70 g body wt) over a period of 10 weeks. Palm oil-fed rats showed higher growth rate and lower triacylglycerol levels than the control group. Hepatic lipase activity was correlated to the liver fat distribution (correlation coefficient, r = +0.682) as seen by histopathological sections and was similar for both the palm oil and the control diets. Palm oil-fed rats exhibited a significantly higher HDL cholesterol to total plasma cholesterol ratio when compared to animals fed the control diet. The triacylglycerol levels correlated inversely to the HDL cholesterol levels (r = -0.536) while the lipoprotein lipase (LPL) activity correlated directly to the LDL level (r = +0.617) for both groups of animals. The fatty acid profiles of adipose and liver tissues and plasma revealed that saturated fatty acids--palmitic and stearic--were preferentially incorporated in liver and adipose tissues and less in the plasma. This accounts for lack of deposition in the arterial wall and for the antithrombotic tendency of palm oil. Thus, our present findings suggest that dietary palm oil may not contribute to the risk for coronary heart disease.     

Relationship of lipoprotein lipase activity to triglyceride uptake in adipose tissue

Fasted rats injected with actinomycin or fed glucose show increased lipoprotein lipase activity of epididymal adipose tissue. Data from the actinomycin-treated animals showed a direct correlation between the lipoprotein lipase activity and the uptake of lipoprotein triglyceride by the epididymal fat pad in vitro and in vivo. Data from the animals fed glucose confirmed these findings in vitro. These data strongly suggest that lipoprotein lipase plays a major role in triglyceride deposition in adipose tissue.     

Effect of ingestion of unsaturated fat on lipolytic activity of rat tissues

Homogenates of some rat tissues, incubated in Tris-maleate buffer containing bovine serum albumin, olive oil emulsion, heparin, and serum, liberated free fatty acids. The total lipolytic activity in tissues of rats fed a low fat, 20% lard, or 20% corn oil diet for 6 wk was measured. Similar activities were found in all the livers, but there was a significant increase in the total lipolytic activity of the mucosa, epididymal fat, and mesenteric tissues after ingestion of an unsaturated fat diet as compared with that containing a more saturated fat. From measurements of the lipolytic activity in the presence of 1 M NaCl or 0.2 M NaF and in the absence and presence of heparin and serum, the conclusion is drawn that more lipoprotein lipase was present in adipose tissue of rats on unsaturated fat diets. An increase in available lipoprotein lipase after unsaturated fat diets may aid in clearing lipids from the blood of these rats and thus in producing the lower blood lipid levels obtained.     

Effects of diet and age on lipoprotein lipase and hepatic triglyceride lipase activities in the rat

Plasma clearance of triglyceride-rich lipoproteins appears decreased in aged humans and rats and may be due to lowered activities of the lipases responsible for lipid degradation. This study was designed to examine differential effects of age and diet on lipoprotein lipase (LPL) activity of adipose and heart tissue and hepatic triglyceride lipase (HTGL) activity. LPL and HTGL activities were examined in 3- and 13-month-old Sprague-Dawley rats after they had consumed either a high-carbohydrate or a high-fat diet for 14 days. The data were analyzed for age and diet differences by two-way analysis of variance. Although animals in the two age groups consumed diets of equal caloric content, the older rats gained less weight. Rats on the high-carbohydrate diet consumed less calories and gained less weight than the fat fed rats in both age groups. Neither heart nor adipose tissue LPL activity differed when examined for age or diet. HTGL activity levels, while not affected by age, were higher in the carbohydrate fed rats (P = 0.014). Regardless of age group, fasting plasma cholesterol levels were significantly higher in the carbohydrate-fed rats than fat-fed rats (P = 0.002). Thus, the diet effect was much stronger than the age effect for HTGL and plasma cholesterol levels.     

Plasma lipoproteins,postheparin plasma lipoprotein lipase activity intralipid half-life,triglyceride secretion rate and liver lipids in the mouse fed different cholesterol diets

Mice (SC), fed a semipurified diet containing cholesterol, cholic acid and sucrose, exhibited, in comparison to control animals (S), an increase in cholesterol, phospholipid and protein of VLDL, LDL₁ and LDL₂, but triglyceride of the same lipoproteins decreased, as did total plasma triglycerides. Postheparin plasma lipoprotein lipase activity of SC animals was 1.72 times that of S mice. At the same time Intralipid half-life in SC mice was decreased by 52%. Triglyceride secretion rate, after Triton WR 1339 treatment, and liver triglyceride content were reduced in SC animals. HDL mass was decreased in SC mice. Mice (AC) fed a standard diet containing cholesterol showed, in comparison to normal fed animals (A), an increase in cholesterol of VLDL, LDL₁ and LDL₂ but triglyceride of the same lipoproteins decreased as did total plasma triglycerides. Postheparin plasma lipoprotein lipase activity of AC animals was unmodified as was Intralipid half-life. In AC animals triglyceride secretion rate, after Triton WR 1339 treatment, was reduced but in a less extent than in SC mice. Liver triglyceride was unmodified. HDL mass was decreased in AC mice.     

Serum lipoprotein composition, lecithin cholesterol acyltransferase and tissue lipase activities in pregnant diabetic rats and their offspring receiving enriched n-3 PUFA diet

The effects of dietary n-3 polyunsaturated fatty acids on lipoprotein concentrations and on lipoprotein lipase (LPL), hepatic triglyceride lipase (HTGL) and lecithin cholesterol acyltransferase (LCAT) activities were studied in streptozotocin-induced diabetic rats during pregnancy and in their macrosomic offspring from birth to adulthood. Pregnant diabetic and control rats were fed Isio-4 diet (vegetable oil) or EPAX diet (concentrated marine omega-3 EPA/DHA oil), the same diets were consumed by pups at weaning. Compared with control rats, diabetic rats showed, during pregnancy, a significant elevation in very low density lipoprotein (VLDL) and low and high density lipoprotein (LDL-HDL(1))-triglyceride, cholesterol and apoprotein B100 concentrations and a reduction in apoprotein A-I levels. HTGL activity was high while LPL and LCAT activities were low in these rats. The macrosomic pups of Isio-4-fed diabetic rats showed a significant enhancement in triglyceride and cholesterol levels at birth and during adulthood with a concomitant increase in lipase and LCAT activities. EPAX diet induces a significant diminution of VLDL and LDL-HDL(1) in mothers and in their macrosomic pups, accompanied by an increase in cholesterol and apoprotein A-I levels in HDL(2-3) fraction. It also restores LPL, HTGL and LCAT activities to normal range. EPAX diet ameliorates considerably lipoprotein disorders in diabetic mothers and in their macrosomic offspring.     

Effects of dietary cholesterol on adipose tissue lipoprotein lipase in the baboon

The effects of infant diet (breast milk or formula containing 2, 30 or 60 mg/dl cholesterol) and subsequent dietary cholesterol (0.02, 1.0 or 1.7 mg/kcal) and fat (saturated or unsaturated) on heparin-releasable lipolytic activity from omental adipose tissue was estimated from 99 baboons of 5-8 years of age. This lipase activity was characterized as lipoprotein lipase based on salt inhibition and apolipoprotein C-II activation. Lipoprotein lipase activity released from adipose tissue by heparin was significantly (P less than 0.002) lower in high cholesterol-fed baboons than in those fed low cholesterol. Most of this difference was due to impaired long-term heparin release of lipoprotein lipase. Adipose tissue lipoprotein lipase increased with increasing fat cell size regardless of diet, but there was no effect of diet on adipocyte size. There were no significant effects of infant cholesterol intake nor adult saturated or unsaturated fat on lipoprotein lipase activity. Adult baboons breast fed as infants had lower adipose tissue lipoprotein lipase activity (P less than 0.07) than adults fed formula as infants.     

Lipoprotein lipase and lipogenic enzyme activities in adipose tissue from rats fed different lipid sources

This work was designed to study the effect of different lipid sources on the activities of lipoprotein lipase and lipogenic enzymes in adipose tissue from rats fedad libitum or energy-controlled diets. Male Wistar rats were fed diets containing 40% of energy as fat (olive oil, sunflower oil, palm oil or beef tallow), for 4 wk. Underad libitum feeding no differences were found among dietary fat groups in final body weight, adipose tissue weights and total body fat. Under energy-controlled feeding, despite isoenergetic intake, rats fed the beef tallow diet gained significantly less weight than rats fed the other three diets. Beef tallow fed rats showed the lowest values for adipose tissue weights and total body fat. When rats had free access to food no effect of dietary lipid source on lipogenic enzyme activities was found. In contrast, under energy-controlled feeding rats fed the beef tallow diet showed significantly higher activities of glucose-6-phosphate dehydrogenase and fatty acid synthase than rats fed the other three diets. Heparin-releasable lipoprotein lipase activity in perirenal and subcutaneous adipose tissues was not different among rats fed olive oil, safflower oil, palm oil or beef tallow. When comparing both adipose tissue anatomical locations, significantly higher activities were found in subcutaneous than in perirenal fat pad independently of dietary fat. In conclusion, under our experimental protocol, lipogenesis in rat adipose tissue does not seem to be affected by dietary fat type.     

Effect of nutrition on subcellular localization of rat fat-cell lipoprotein lipase.

This study supports the possibility for multiple subcellular forms of lipoprotein lipase. 1. The total activity of lipoprotein lipase per g of intact epididymal adipose tissue from fed rats is much higher than that from starved rats. 2. The isolated fat-cells of fed and of starved rats have lipoprotein lipase of almost the same activity per g of fat-pads. The isolated fat-cells of starved rats have a much higher proportion of total activity per g of the intact tissue than do those of fed rats. 3. Under the conditions of homogenization used, only a small proportion of the total activity per g of intact tissue from fed rats was associated with the fat layer which floated to the top of the homogenate during low-speed centrifugation. The different proportions of the specific enzyme activity found in each subcellular fraction are described. 4. Lipoprotein lipase from plasma membranes and microsomal fractions from starved and fed rats was purified by affinity chromatography. 5. The total activity of microsomal lipoprotein lipase per g of intact adipose tissue is enhanced by a normal diet. 6. In intact epididymal adipose tissue from fed rats, the activity per g of tissue of lipoprotein lipase of plasma membranes is much higher than that in the same fraction from starved rats. By contrast, the activities per g of tissue in plasma membranes obtained from starved or from fed rats by collagenase treatment were similar.     

A comparative study on hypolipidemic activities of high and low molecular weight chitosan in rats

The hypolipidemic activities of high (712.6kDa) and low (39.8kDa) molecular weight chitosan (HMWC and LMWC) were evaluated in rats fed high-fat diets. Thirty-two male Sprague-Dawley rats in four groups were fed on three high-fat diets with each of them containing HMWC, LMWC or cellulose (high-fat control), and a control normal-fat diet for eight weeks. Compared with HMWC group, LMWC group showed decreased body weight gain, serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C), as well as decreased liver triglyceride (TG). Fecal fat and cholesterol of LMWC group was lower than those of HMWC group. However, the activities of liver and serum lipoprotein lipase (LPL) of LMWC group were increased compared with HMWC group. The obtained results suggested that hypolipidemic activity of LMWC was better than HMWC, which might be partially attributed to the increase of serum and liver LPL activities.     

Angptl3-null mice show low plasma lipid concentrations by enhanced lipoprotein lipase activity.

Angiopoietin-like 3 (ANGPTL3) is a secreted protein with both angiogenesis and lipid metabolism functions. We generated knockout mice that failed to express the Angptl3 gene, and analyzed the lipid metabolism. Angptl3-null mice, fed a normal diet or a high-fat, high-calorie (HFC) diet, revealed markedly low plasma lipid concentrations, especially plasma triglyceride concentration, although the body weight and liver weight were not different between Angptl3-null mice and wild-type mice. Angptl3-null mice fed an HFC diet also revealed a significantly reduced epididymal adipose tissue weight despite there being no difference in adipocyte size between them and wild-type mice. A triglyceride clearance study indicated that the lower plasma triglyceride concentration in Angptl3-null mice was caused by an accelerated clearance of triglyceride. In fact, lipoprotein lipase and hepatic lipase activities in the post-heparin plasma of Angptl3-null mice were 1.57 times and 1.42 times higher than those of wild-type mice, respectively. These results suggest that ANGPTL3 may have an effect not only on lipid metabolism but also on adipose formation.     

Effect of egg cholesterol and dietary fats on plasma lipids, lipoproteins, and apoproteins of normal women consuming natural diets

Nine normal women, 22 to 37 years old, consumed controlled quantities of natural foods to test their responses to dietary cholesterol and saturated fat. All diets contained, as percentage of calories, 14% protein, 31% fat, and 55% carbohydrate. The main sources of polyunsaturated and saturated fats were corn oil and lard, respectively, and egg yolk was used for cholesterol supplementation. All subjects participated in four diet protocols of 15 days duration, and each diet period was separated by 3 weeks without diet control. The first diet (corn) was based on corn oil, had a polyunsaturated to saturated fat ratio (P/S) of 2.14, and contained 130 mg of cholesterol. The second diet (corn+) was identical to the first but contained a total of 875 mg of cholesterol. The third diet (lard) was based on lard, had a P/S ratio of 0.64, and contained 130 mg of cholesterol. The fourth diet (lard+) was identical to the third, but contained 875 mg of cholesterol per day. Changes of the plasma lipid, lipoprotein and apoprotein parameters relative to the corn diet were as follows: the corn+ diet significantly increased total plasma cholesterol, HDL-cholesterol, LDL-cholesterol, and apoB levels; the lard diet significantly increased total cholesterol, HDL-cholesterol, and apoB; and the lard+ diet significantly increased the total cholesterol, HDL-cholesterol, LDL-cholesterol, and apoA-I and apoB levels. There were no significant variations in VLDL-cholesterol, triglyceride, or apoE levels with these diets. The diets affected both the number of lipoprotein particles as well as the composition of LDL and HDL. Compared to the corn diet, cholesterol and saturated fat each increased the number of LDL particles by 17% and 9%, respectively, and the cholesterol per particle by 9%. The combination of saturated fat and cholesterol increased particle number by 18% and particle size by 24%. Switching from lard+ to lard, corn+, or corn diets reduced LDL-cholesterol of the group by 18%, 11%, and 28%, respectively, while a large inter-individual variability was noted. In summary, dietary fat and cholesterol affect lipid and lipoprotein levels as well as the particle number and chemical composition of both LDL and HDL. There is, however, considerable inter-individual heterogeneity in response to diet.     

Dietary fish oil reverse epididymal tissue adiposity, cell hypertrophy and insulin resistance in dyslipemic sucrose fed rat model small star, filled

The present work was designed to assess the possible benefits of (7% w/w) dietary fish oil in reversing the morphological and metabolic changes present in the adipose tissue of rats fed an SRD for a long time. With this purpose, in the epididymal fat tissue, we investigated the effect of dietary fish oil upon: i) the number, size and distribution of cells, ii) the basal and stimulated lipolysis, iii) the lipoprotein lipase (LPL) and the glucose 6-phosphate dehydrogenase activities, and iv) the antilipolytic action of insulin. The study was conducted on rats fed an SRD during 120 days with fish oil being isocaloric substituted for corn oil for 90-120 days in half the animals. Permanent hypertriglyceridemia, insulin resistance and abnormal glucose homeostasis were present in the rats before the source of fat in the diet was replaced. The major new findings of this study are the following: i) Dietary fish oil markedly reduced the fat pads mass, the hypertrophy of fat cells and improved the altered cell size distribution. ii) The presence of fish oil in the diet corrected the inhibitory effect of high sucrose diet upon the antilipolytic action of insulin, reduced the "in vitro" enhanced basal lipolysis and normalized isoproterenol-stimulated lipolysis. Fat pads lipoprotein lipase activity decreased reaching values similar to those observed in age-matched controls fed a control diet (CD). These effects were not accompanied by any change in rat body weight. All these data suggest that the dyslipemic rats fed a moderate amount of dietary fish oil constitute a useful animal model to study diet-regulated insulin action.     

Influence of partial replacement of starch by sucrose in high fat-cholesterol diet on serum lipoprotein responses of cynomolgus monkeys

The influence of partial replacement of starch by sucrose on dietary cholesterol-induced serum lipoprotein responses was examined in 10 male cynomolgus monkeys (Macaca fascicularis). In a crossover design two semipurified diets provided either starch or starch and sucrose (1:1) as carbohydrate (49% by calories) with 0.4 mg cholesterol/kcal. Six weeks of starch + sucrose diet resulted in significantly reduced levels (mean +/- SE, mg/dl) of serum total cholesterol (264 +/- 9 vs 244 +/- 8) and apo B (110 +/- 6 vs 96 +/- 6) when compared with starch diet, whereas serum triglyceride levels remained similar between diets. With respect to changes in lipids and apolipoproteins (A-I or B) of very low (VLDL), low (LDL), intermediate (IDL), and high (HDL) density lipoproteins, starch + sucrose diet significantly increased VLDL-apo B (+34%), and decreased LDL-cholesterol (-18%) and LDL-apo B (-15%) as compared with starch alone; no differences were found in IDL and HDL between diets. The relative proportion of starch to sucrose in a diet appears to influence the magnitude of response of lipoproteins to dietary cholesterol.     

Tissue-specific alterations in lipoprotein lipase activity in copper-deficient rats

Copper deficiency results in alterations in lipid metabolism that include elevations in serum cholesterol and triglycerides and a decrease in whole-body respiratory quotient. Copper-deficient animals are also leaner even though electron micrographs of the myocardium present increased lipid droplet accumulation. To address whether a compromised copper status impacts triglyceride deposition in a tissue-specific manner, the activity of lipoprotein lipase was measured in adipose tissue and cardiac and skeletal muscle. Weanling rats fed a copper-restricted diet (<1 ppm) for 6 wk demonstrated a greater than twofold increase in cardiac lipoprotein lipase activity concomitant with a significant reduction in adipose tissue lipoprotein lipase activity. Skeletal muscle lipoprotein lipase activity was not altered by the copper-deficient state. The results of this study suggest that copper deficiency may induce a tissue-specific alteration in lipoprotein lipase activity in rats, which may contribute to the notable deposition of lipid substance in myocardium and the concomitant general body leanness.