PLTP activity in premenopausal women. Relationship with lipoprotein lipase, HDL, LDL, body fat, and insulin resistance

Plasma phospholipid transfer protein (PLTP) is thought to play a major role in the facilitated transfer of phospholipids between lipoproteins and in the modulation of high density lipoprotein (HDL) particle size and composition. However, little has been reported concerning the relationships of PLTP with plasma lipoprotein parameters, lipolytic enzymes, body fat distribution, insulin, and glucose in normolipidemic individuals, particularly females. In the present study, 50 normolipidemic healthy premenopausal females were investigated. The relationships between the plasma PLTP activity and selected variables were assessed. PLTP activity was significantly and positively correlated with low density lipoprotein (LDL) cholesterol (r(s) = 0.53), apoB (r(s) = 0.44), glucose (r(s) = 0.40), HDL cholesterol (r(s) = 0.38), HDL(3) cholesterol (r(s) = 0.37), lipoprotein lipase activity (r(s) = 0.36), insulin (r(s) = 0.33), subcutaneous abdominal fat (r(s) = 0.36), intra-abdominal fat (r(s) = 0.29), and body mass index (r(s) = 0.29). HDL(2) cholesterol, triglyceride, and hepatic lipase were not significantly related to PLTP activity. As HDL(2) can be decreased by hepatic lipase and hepatic lipase is increased in obesity with increasing intra-abdominal fat, the participants were divided into sub-groups of non-obese (n = 35) and obese (n = 15) individuals and the correlation of PLTP with HDL(2) cholesterol was re-examined. In the non-obese subjects, HDL(2) cholesterol was found to be significantly and positively related to PLTP activity (r(s) = 0.44). Adjustment of the HDL(2) values for the effect of hepatic lipase activity resulted in a significant positive correlation between PLTP and HDL(2) (r(s) = 0.41), indicating that the strength of the relationship between PLTP activity and HDL(2) can be reduced by the opposing effect of hepatic lipase on HDL(2) concentrations. We conclude that PLTP-facilitated lipid transfer activity is related to HDL and LDL metabolism, as well as lipoprotein lipase activity, adiposity, and insulin resistance.     

Chromium picolinate and conjugated linoleic acid do not synergistically influence diet- and exercise-induced changes in body composition and health indexes in overweight women

This study assessed the effects of combined chromium picolinate (CP) and conjugated linoleic acid (CLA) supplementation on energy restriction and exercise-induced changes in body composition, glucose metabolism, lipid lipoprotein profile and blood pressure in overweight, premenopausal women. For 12 weeks, 35 women [age 36+/-1 years (mean+/-S.E.M.); BMI 28.0+/-0.5 kg/m2] were counseled to consume a 2092 kJ/day (500 kcal/day) energy deficit diet and performed 30 min of moderate-intensity walking or jogging 5 days/week. The women were randomly assigned to ingest either CP-CLA [400 mug chromium (Cr), 1.8 g CLA in 2.4 g tonalin oil, n=19] or placebo (<0.1 microg Cr, 2.4 g canola oil, n=16). Compared to baseline, urinary Cr excretion increased 22-fold, plasma CLA isomer 18:2 (c9,t11) content increased 79% and plasma CLA isomer 18:2 (t10,c12) became detectable in CP-CLA and were unchanged in Placebo. Over time, body weight decreased 3.5+/-0.5% (CP-CLA -2.6+/-0.5; placebo -2.5+/-0.5 kg) and fat mass decreased 8.9+/-1.3% (CP-CLA -2.7+/-0.5, placebo -2.4+/-0.5 kg), with no differences in responses between groups. Fasting blood hemoglobin A1c, plasma glucose and insulin, a homeostatic assessment of insulin resistance, serum total cholesterol (CHOL), high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol, triacylglycerol (TG), CHOL/HDL ratio, TG/HDL ratio and sitting systolic and diastolic blood pressures were not changed over time or influenced by CP-CLA. The use of a combined CP and CLA supplement for 3 months does not affect diet- and exercise-induced changes in weight and body composition or improve indexes of metabolic and cardiovascular health in young overweight women.     

The effects of 20 days bed rest on serum lipids and lipoprotein concentrations in healthy young subjects

The effects of 20 days bed rest (BR) on serum lipids and lipoprotein concentrations were investigated in 23 healthy young subjects (13 males and 10 females, aged 19 to 25 yr.). After 20 days BR, VO2max was reduced in both genders, but body composition did not change. The ratio of glucose area to insulin area during an oral glucose tolerance test decreased gradually throughout BR, which suggested a decrease in insulin sensitivity. Estimated changes in plasma volume from the beginning of BR were largest at day 3 of BR (-9.1% in females and -3.4% in males) and seemed to return the initial level at the end of BR in both genders. The increase in serum triglycerides and the decrease in high density lipoprotein (HDL) cholesterol, and apolipoprotein AI were observed in both genders during BR. In a smaller study of 4 males and 5 females, 20 days BR was associated with a decrease in HDL, cholesterol, a decrease in apolipoprotein AI and apolipoprotein AII, decrease in a plasma postheparin lipoprotein lipase activity and an increase in very low density lipoprotein triglyceride. Overall, the data suggested that the decrease in lipoprotein lipase activity and insulin sensitivity may contribute to the impairment in HDL metabolism.     

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.     

Effects of resistance versus aerobic training on coronary artery disease risk factors

Individuals exhibiting "the metabolic syndrome" have multiple coronary artery disease risk factors, including insulin resistance, hyperlipidemia, hypertension, and android obesity. We performed a randomized trial to compare the effects of aerobic and resistance training regimens on coronary risk factors. Twenty-six volunteers who exhibited android obesity and at least one other risk factor for coronary artery disease were randomized to aerobic or resistance training groups. Body mass index, waist-to-hip ratio, glucose, insulin, body composition, 24-hr urinary albumin, fibrinogen, blood pressure, and lipid profile were measured at baseline and after 10 weeks of exercise training. Both groups showed a significant reduction in waist-to-hip ratio and the resistance training group also showed a reduction in total body fat. There was no significant change in mean arterial blood pressure in either group. Fasting plasma glucose, insulin, total cholesterol, low-density lipoprotein (LDL) cholesterol, and triglycerides were unchanged in both groups. High-density lipoprotein (HDL) cholesterol increased (13%) with aerobic training only. Plasma fibrinogen was increased (28% and 34%, P < 0.02) in both groups and both groups showed a significant decrease (34% and 28%, P < 0.03) in microalbuminuria after their respective training regimen. In conclusion, resistance training was effective in improving body composition of middle-aged obese sedentary males. Only aerobic training was effective in raising HDL cholesterol. More studies are warranted to assess the effects of exercise on plasma fibrinogen and microalbuminuria.     

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.     

Skeletal muscle adiposity is associated with serum lipid and lipoprotein levels in Afro‐Caribbean men

Objective: When compared with other ethnic groups, African ancestry individuals have lower triglycerides and higher High‐density lipoprotein cholesterol (HDL‐C) levels, although the mechanisms for these differences remain unclear. A comprehensive array of factors potentially related to fasting serum lipid and lipoprotein levels in African ancestry men was evaluated. Design and Methods: Men (1,821) underwent dual‐energy X‐ray absorptiometry measures of total body fat and quantitative computed tomography assessments of calf skeletal muscle adiposity [subcutaneous and intermuscular adipose tissue (AT), and muscle density as a measure of intra‐muscular AT]. Results: Multivariable linear regression analysis identified age (?), total body fat (+), subcutaneous AT (?), fasting glucose (+), fasting insulin (+), diastolic blood pressure (+), and non‐African ancestry (+) as independent correlates of triglycerides (all P < 0.05). Total body fat (+), intra‐muscular AT (?), and diastolic blood pressure (+) were independent correlates of Low‐density lipoprotein cholesterol (LDL‐C) (all P < 0.001). Age (+), waist circumference (?), fasting insulin (?), physical activity (+), and alcohol intake (+) were independent correlates of HDL‐C (all P < 0.05). Conclusions: A novel relationship between skeletal muscle adiposity and serum lipid and lipoprotein levels in African ancestry men, independent of total and central adiposity was illuminated. In African ancestry populations, genetic factors are likely a significant determinant of triglycerides levels.     

Experimental hyperthyroidism in man: effects on plasma lipoproteins, lipoprotein lipase and hepatic lipase

We have studied the effects of triiodothyronine administration (20-40 micrograms three times daily over one week) in six healthy young men, on the activities of lipoprotein lipase and hepatic lipase and on plasma lipoprotein concentrations. Hepatic lipase activity in post-heparin plasma rose by 46 +/- 25% (p less than 0.025), whereas the activity of lipoprotein lipase did not change significantly. Plasma cholesterol concentrations decreased by about 20% (p less than 0.025), whereas there was no change in plasma triglyceride levels. The fall in plasma cholesterol could be accounted for by a reduction of HDL cholesterol (-11%, p less than 0.025) as well as LDL cholesterol (-27%, p less than 0.025). The data emphasize the role of hepatic lipase in the lipoprotein alterations associated with thyroid dysfunction.     

Pre-heparin plasma lipoprotein lipase mass: correlation with intra-abdominal visceral fat accumulation.

OBJECTIVE: To determine how lipoprotein lipase mass in the pre-heparin plasma is affected by body fat distribution, which is known to be closely related to lipid disorder, either directly or through insulin resistance. SUBJECTS: A total of 57 subjects consisting of 50 hyperlipidemic and 7 normolipidemic subjects (age 54 +/- IIy; 31 men, 26 women; body mass index 24+/- 2.5 kg/m2; serum total cholesterol 6.4+/-1.5 mmol/l; triglycerides, 2.4 +/- 1.7 mmol/l; HDL-cholesterol 1.3 +/- 0.5 mmol/l) were enrolled. MEASUREMENTS: We investigated the correlation between pre-heparin plasma LPL mass and intra-abdominal visceral fat area (or subcutaneous fat area) evaluated by computed tomography, and serum lipids and lipoproteins. RESULTS: Pre-heparin plasma LPL mass correlated inversely against intra-abdominal visceral fat area (r = - 0.51, p < 0.0001) and body mass index (r = - 0.46, p = 0.0003), but did not show any significant correlation with subcutaneous fat area. Pre-heparin plasma LPL mass had a positive correlation with serum high density lipoprotein cholesterol (r = 0.45, p = 0.0004) and a negative correlation against serum triglycerides (r = - 0.48, p = 0.0002). CONCLUSIONS: Pre-heparin plasma LPL mass is closely associated with intra-abdominal fat distribution, and the measurement of its value gives useful information concerning metabolic disorder.     

Role of insulin in regulation of high density lipoprotein metabolism

The effect of alloxan-induced insulin deficiency on high density lipoprotein (HDL) metabolism was studied in rabbits. Rabbits with alloxan-induced diabetes had significantly higher (P less than 0.001, mean +/- SEM) plasma concentrations of glucose (541 +/- 13 vs. 130 +/- 2 mg/dl), triglyceride (2851 +/- 332 vs. 101 +/- 10 mg/dl), and total plasma cholesterol (228 +/- 55 vs. 42 +/- 4 mg/dl) than did normal control rabbits. However, diabetic rabbits had lower plasma HDL-cholesterol (7.2 +/- 1 vs. 51.3 +/- 1.3 mg/dl, P less than 0.001) and HDL apoA-I (38.3 +/- 6.0 vs. 87.2 +/- 4.3 mg/dl, P less than 0.001) concentrations. HDL kinetics were compared in diabetic and normal rabbits, using either 125I-labeled HDL or HDL labeled with 125I-labeled apoA-I, and it was demonstrated that HDL fractional catabolic rate (FCR) was slower and residence time was longer in the diabetic rabbits when either tracer was used. The slow FCR and the low apoA-I pool size led to reduced apoA-I/HDL synthetic rate in diabetic rabbits (0.97 +/- 0.11 vs. 0.34 +/- 0.07 mg per kg per hr). Thus, the reduced plasma HDL-cholesterol concentrations seen in rabbits with alloxan-induced insulin deficiency was associated with a lower total apoA-I/HDL synthetic rate. Since insulin treatment restored to normal all of the changes in plasma lipoprotein concentration and kinetics seen in diabetic rabbits, it is unlikely that the phenomena observed were secondary to a nonspecific toxic effect of alloxan. These data strongly support the view that insulin plays an important role in regulation of HDL metabolism.     

Castelli risk indexes 1 and 2 are higher in major depression but other characteristics of the metabolic syndrome are not specific to mood disorders

Aims

This study examined whether Castelli risk indexes 1 (total/high-density lipoprotein (HDL) cholesterol) and 2 (low density lipoprotein (LDL)/HDL cholesterol) and other shared metabolic disorders might underpin the pathophysiology of the metabolic syndrome, major depression or bipolar disorder.

Main methods

This cross-sectional study examined 92 major depressed, 49 bipolar depressed and 201 normal controls in whom the Castelli risk indexes 1 and 2 and key characteristics of the metabolic syndrome, i.e. waist/hip circumference, body mass index (BMI), systolic/diastolic blood pressure, total cholesterol, low-density lipoprotein (LDL) and HDL cholesterol, triglycerides, insulin, glucose, hemoglobin A1c (HbA1c) and homocysteine were assessed.

Key findings

Castelli risk indexes 1 and 2 were significantly higher in major depressed patients than in bipolar disorder patients and controls. There were no significant differences in waist or hip circumference, total and LDL cholesterol, triglycerides, plasma glucose, insulin, homocysteine and HbA1c between depression and bipolar patients and controls. Bipolar patients had a significantly higher BMI than major depressed patients and normal controls.

Significance

Major depression is accompanied by increased Castelli risk indexes 1 and 2, which may be risk factors for cardiovascular disease. Other key characteristics of the metabolic syndrome, either metabolic biomarkers or central obesity, are not necessarily specific to major depression or bipolar disorder.     

Overexpression of lipoprotein lipase in transgenic Watanabe heritable hyperlipidemic rabbits improves hyperlipidemia and obesity

Lipoprotein lipase (LPL) is the rate-limiting enzyme for the hydrolysis of the triglyceride-rich lipoproteins and plays a critical role in lipoprotein and free fatty acid metabolism. Genetic manipulation of LPL may be beneficial in the treatment of hypertriglyceridemias, but it is unknown whether increased LPL activity may be effective in lowering plasma cholesterol and improving insulin resistance in familial hypercholesterolemic patients. To test the hypothesis that stimulation of LPL expression may be used as an adjunctive therapy for treatment of homozygous familial hypercholesterolemia, we have generated transgenic (Tg) Watanabe heritable hyperlipidemic (WHHL) rabbits that overexpress the human LPL transgene and compared their plasma lipid levels, glucose metabolism, and body fat accumulation with those of non-Tg WHHL rabbits. Overexpression of LPL dramatically ameliorated hypertriglyceridemia in Tg WHHL rabbits. Furthermore, increased LPL activity in male Tg WHHL rabbits also corrected hypercholesterolemia (544 +/- 52 in non-Tg versus 227 +/- 29 mg/dl in Tg, p < 0.01) and reduced body fat accumulation by 61% (323 +/- 27 in non-Tg versus 125 +/- 21ginTg, p < 0.01), suggesting that LPL plays an important role in mediating plasma cholesterol homeostasis and adipose accumulation. In addition, overexpression of LPL significantly suppressed high fat diet-induced obesity and insulin resistance in Tg WHHL rabbits. These results imply that systemic elevation of LPL expression may be potentially useful for the treatment of hyperlipidemias, obesity, and insulin resistance.     

Familial aggregation of metabolic syndrome and its components in a large Chinese population

Objective: To investigate the familial aggregation of metabolic syndrome (MetS) and its components in the Chinese. Methods and Procedures: A total of 17,954 subjects from 5,224 families with multiple siblings aged 25–64 years old (mean age 45.8 years, 51.6% male) were enrolled from a rural area of Anhui Province of China during 2004–2005. Anthropometric measurement, body composition, blood pressure, plasma lipids, and fasting glucose and insulin, as well as a questionnaire interview, were obtained from each participant. Results: Significant correlations among siblings were observed in all the traits examined, including BMI, waist circumference, total body and abdominal fat percentage, fasting plasma glucose (FPG) and insulin, insulin resistance index of homeostatic model assessment (HOMA‐IR), total cholesterol, triglyceride, high‐density lipoprotein cholesterol (HDL‐C), low‐density lipoprotein cholesterol, and blood pressure, after adjustment for age, gender and some other covariates. The correlation coefficients varied from 0.18 for FPG to 0.42 for HDL‐C. In stratified analyses, we found siblings with a smaller age gap among them had higher intraclass correlation coefficients (ICCs) for most of the above phenotypes than those with a greater age difference, and the correlation of systolic blood pressure (SBP) was stronger in male siblings than that in female. If the eldest sibling is affected by MetS or any of its components, younger siblings bear a twofold to threefold higher risk for developing MetS or any of its components than those with a healthy eldest sibling. Discussion: Our study demonstrated a significant familial resemblance as regards MetS and its components among the Chinese. Further studies are warranted to investigate specific genetic and environmental factors related to MetS in this population.     

Influence of insulin sensitivity and the TaqIB cholesteryl ester transfer protein gene polymorphism on plasma lecithin:cholesterol acyltransferase and lipid transfer protein activities and their response to hyperinsulinemia in non-diabetic men.

Lecithin:cholesteryl acyl transferase (LCAT), cholesteryl ester transfer protein (CETP), phospholipid transfer protein (PLTP), and lipoprotein lipases are involved in high density lipoprotein (HDL) metabolism. We evaluated the influence of insulin sensitivity and of the TaqIB CETP gene polymorphism (B1B2) on plasma LCAT, CETP, and PLTP activities (measured with exogenous substrates) and their responses to hyperinsulinemia. Thirty-two non-diabetic men without hyperlipidemia were divided in quartiles of high (Q(1)) to low (Q(4)) insulin sensitivity. Plasma total cholesterol, very low + low density lipoprotein cholesterol, triglycerides, and apolipoprotein (apo) B were higher in Q(4) compared to Q(1) (P < 0.05 for all), whereas HDL cholesterol and apoA-I were lowest in Q(4) (P < 0.05 for both). Plasma LCAT activity was higher in Q(4) than in Q(1) (P < 0. 05) and PLTP activity was higher in Q(4) than in Q(2) (P < 0.05). Insulin sensitivity did not influence plasma CETP activity. Postheparin plasma lipoprotein lipase activity was highest and hepatic lipase activity was lowest in Q(1). Insulin infusion decreased PLTP activity (P < 0.05), irrespective of the degree of insulin sensitivity. The CETP genotype exerted no consistent effects on baseline plasma lipoproteins and LCAT, CETP, and PLTP activities. The decrease in plasma PLTP activity after insulin was larger in B1B1 than in B2B2 homozygotes (P < 0.05). These data suggest that insulin sensitivity influences plasma LCAT, PLTP, lipoprotein lipase, and hepatic lipase activities in men. As PLTP, LCAT, and hepatic lipase may enhance reverse cholesterol transport, it is tempting to speculate that high levels of these factors in association with insulin resistance could be involved in an antiatherogenic mechanism. A possible relationship between the CETP genotype and PLTP lowering by insulin warrants further study.     

Long-term effects of large-volume liposuction on metabolic risk factors for coronary heart disease

Abdominal obesity is associated with metabolic risk factors for coronary heart disease (CHD). Although we previously found that using liposuction surgery to remove abdominal subcutaneous adipose tissue (SAT) did not result in metabolic benefits, it is possible that postoperative inflammation masked the beneficial effects. Therefore, this study provides a long-term evaluation of a cohort of subjects from our original study. Body composition and metabolic risk factors for CHD, including oral glucose tolerance, insulin resistance, plasma lipid profile, and blood pressure were evaluated in seven obese (39 +/- 2 kg/m(2)) women before and at 10, 27, and 84-208 weeks after large-volume liposuction. Liposuction surgery removed 9.4 +/- 1.8 kg of body fat (16 +/- 2% of total fat mass; 6.1 +/- 1.4 kg decrease in body weight), primarily from abdominal SAT; body composition and weight remained the same from 10 through 84-208 weeks. Metabolic endpoints (oral glucose tolerance, homeostasis model assessment of insulin resistance, blood pressure and plasma triglyceride (TG), high-density lipoprotein (HDL)-cholesterol, and low-density lipoprotein (LDL)-cholesterol concentrations) obtained at 10 through 208 weeks were not different from baseline and did not change over time. These data demonstrate that removal of a large amount of abdominal SAT by using liposuction does not improve CHD metabolic risk factors associated with abdominal obesity, despite a long-term reduction in body fat.     

Reductive effect of body weight in C57BL/6J mice fed a high-fat diet by Saesaengmyung Diet

The Saesaengmyung Diet (SD) is a newly developed dietary product to help control weight. The aim of this study was to evaluate whether SD combined with a high-fat (HF) diet could influence body weight, fat accumulation, and glucose levels in blood. C57BL/6J mice were fed for 8 weeks with a standard diet, an HF diet, and an HF + 10% or HF + 20% SD diet. Body weight was recorded weekly, and plasma levels of total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and glucose were analyzed at the end of the study. Weight increases in the 10% or 20% SD group were significantly less than in the HF diet group (p < 0.05). Plasma total cholesterol level significantly decreased by 33.5% in the 10% SD group and 38.8% in the 20% SD group, but the LDL cholesterol, HDL cholesterol, and glucose levels in the SD groups were not significantly changed. Our findings indicate that SD may be beneficial to overweight individuals in the reduction of weight gain induced by an HF diet.     

Circulating lipids and lipoproteins in glycogen storage disease type I with nocturnal intragastric feeding

With the advent of nocturnal intragastric feeding which protects against acute metabolic complications and promotes growth, patients with glycogen storage disease type I are attracting less attention. However, several biochemical alterations persist and suggest that the long-term risk of atherosclerotic heart disease remains high. Persisting hypertriglyceridemia and hypercholesterolemia were found in seven glycogen storage disease type I subjects, six of them following 5-6 yr of nocturnal intragastric feeding. When compared to ten age-matched controls, the patients showed significantly (P less than 0.001) higher low density lipoprotein cholesterol (LDL-C) (247.7 +/- 46.8 vs. 115.3 +/- 5.0 mg/dl) and lower high density lipoprotein cholesterol (HDL-C) (26.4 +/- 3.4 vs. 55.8 +/- 2.9 mg/dl). Triglyceride (TG) enrichment with cholesteryl ester depletion characterized the lipoprotein classes. The diameters of very low density lipoproteins (VLDL) and LDL were larger, while that of HDL was smaller and consistent with the predominance of the HDL3 subclass and a lower apoA-I/apoA-II ratio. The raised levels of TG appeared attributable not only to the well-described lipogenesis, but also to impaired catabolism of fat, as evidenced by the significantly (P less than 0.001) decreased activity of both peripheral lipoprotein lipase (3.17 +/- 0.43 vs. 14.15 +/- 0.50 mumol FFA.ml-1.hr-1) and hepatic lipase (1.88 +/- 0.30 vs. 4.83 +/- 0.90). This may well explain the high concentration of intermediate density lipoprotein (IDL) and the impaired conversion of HDL3 to HDL2. Low apoC-II/apoC-III1 could be related to defective lipoprotein lipase activity. These data suggest that glycogen storage disease type I patients on nocturnal intragastric feeding remain at risk for atherosclerosis and its complications.     

Beta-endorphin and insulin/glucose responses to different meals in obesity.

The responses of plasma beta-endorphin, insulin and glucose to two different isocaloric mixed meals--high carbohydrate (CHO meal) and high fat (fat meal)--were assessed in women with android obesity before (n = 11) as well as after (n = 5) weight reduction, and in normal-weight controls (n = 8). Basal plasma beta-endorphin concentrations in the obese subjects (7.7 +/- 1.2 pmol/l) were significantly (p less than 0.005) higher than in the controls (3.8 +/- 0.5 pmol/l) and were not influenced by weight loss. Fasting plasma levels and the integrated releases of insulin and glucose, both after the CHO meal and after the fat meal were significantly higher in the obese subjects than in the controls. The fat meal induced no changes in beta-endorphin levels in either group. After the CHO meal a significant decrease in plasma beta-endorphin concentration was observed only in the obese group before weight reduction. An influence on beta-endorphin release by macronutrients is hypothesized.     

Acute and chronic effects of a 24-hour intravenous triglyceride emulsion challenge on plasma lecithin: cholesterol acyltransferase, phospholipid transfer protein, and cholesteryl ester transfer protein activities.

Lecithin:cholesterol acyltransferase (LCAT), phospholipid transfer protein (PLTP), and cholesteryl ester transfer protein (CETP) are key factors in remodeling of high density lipoproteins (HDL) and triglyceride-rich lipoproteins. We examined the effect of a large, 24 h intravenous fat load on plasma lipids and free fatty acids (FFA) as well as on plasma LCAT, PLTP, and CETP activity levels in 8 healthy men. The effect of concomitant insulin infusion was also studied, with 1 week between the study days. During Lipofundin(R) infusion, plasma triglycerides and FFA strongly increased after 8 and 24 h (P < 0.001), whereas HDL cholesterol decreased (P < 0.01). The increase in triglycerides was mitigated with concomitant insulin infusion (P < 0.05 from without insulin). Plasma LCAT activity increased by 17.7 +/- 7.7% after 8 h (P < 0.001) and by 26.1 +/- 11. 1% after 24 h (P < 0.001), PLTP activity increased by 19.7 +/- 15.6% after 24 h (P < 0.001), but CETP activity remained unchanged. Concomitant insulin infusion blunted the increase in plasma LCAT activity (P < 0.05 from without insulin), but not that in PLTP activity. One week after the first fat load, plasma non-HDL cholesterol (P < 0.02), and triglycerides (P = 0.05) were increased, whereas HDL cholesterol was decreased (P < 0.02). Plasma CETP and PLTP activity levels were increased by 34.8 +/- 30.4% (P < 0.02) and by 15.9 +/- 6.4% (P < 0.02), respectively, but LCAT activity was then unaltered. In summary, plasma LCAT, PLTP, and CETP activity levels are stimulated by a large intravenous fat load, but the time course of their responses and the effects of insulin coadministration are different. Changes in plasma LCAT and PLTP activities may be implicated in HDL and triglyceride-rich lipoprotein remodeling under the present experimental conditions.     

The Effect of Boron on Some Biochemical Parameters in Experimental Diabetic Rats

In this study, we evaluated the effect of boron (B) as boric acid (BA) on body weight (b.w.); blood glucose; plasma insulin; lipase and paraoxonase (PON1) activities; and serum triglyceride, total cholesterol, high-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol, lipid peroxidation (MDA), and total antioxidant capacity (TAC) in streptozotocin (STZ)-induced experimental diabetes in rats. Sixty Wistar albino rats (200–250 g) were divided into six groups of ten. The groups received the following treatment: group 1, control group; group 2, 50 mg/kg (b.w.) i.p. STZ-induced diabetes; group 3, 5 mg/kg (b.w.) B; group 4, 10 mg/kg (b.w.) B; group 5, diabetes + 5 mg/kg (b.w.) B; and group 6, diabetes + 10 mg/kg (b.w.) B. The experiment lasted 4 weeks. Increased serum MDA levels with diabetes were significantly reduced and although it is not statistically significant, serum TAC levels approached to values of control group; also, insignificant increases were observed in HDL cholesterol levels in experimental diabetic rats with treatment 5 and 10 mg/kg B. Furthermore, body weight, plasma insulin, and lipase activities increased insignificantly, blood glucose and serum LDL cholesterol decreased significantly, and total cholesterol levels decreased insignificantly in the diabetes + 10 mg/kg B group. There was no difference between the groups in terms of plasma PON1 activities and serum triglyceride levels. In conclusion, B may have beneficial effects on some biochemical parameters changes in experimental diabetes, and in order to determine the full effect of this element on the metabolism, further studies are required which use various dosages and compounds of B.