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.     

Age, insulin, SHBG and sex steroids exert secondary influence on plasma leptin level in women

AIM: As the link between body fat and leptin is well known, the aim of the study was to seek for secondary regulators of plasma leptin level. PATIENTS: 86 women (mean: age 47.0+/-14.3 years; estradiol 50.0+/-60.6 ng/l; FSH 52.4+/-42.9 IU/l; BMI 26.9+/-5.9) divided into three groups according to their BMI. Group A: 39 normal weight women (mean: age 44.4+/-16.0 years; estradiol 69.6+/-79.8 ng/l; FSH 50.4+/-47.7 IU/l; BMI 22.9+/-1.3). Group B: 27 overweighted women (mean: age 55.0+/-6.4 years; estradiol 25.1+/-17.2 ng/l; FSH 75.6+/-26.3 IU/l; BMI 27.7+/-1.6). Group C: 21 obese women with mean: age 48.7+/-12.2 years; estradiol 36.9+/-44.0 ng/l; FSH 42.3+/-36.6 IU/l and BMI 34.6+/-4.9. METHODS: Standard clinical evaluation and hormone evaluation (LH, FSH, prolactin, estradiol, leptin, insulin-like growth factor-I (IGF-I), human growth hormone (hGH), insulin-like growth factor binding protein-3 (IGFBP-3), insulin, dihydroepiandrosterone sulphate (DHEAS), sex hormone binding globin (SHBG) and testosterone were done in basic condition which levels of were measured by RIA kits. Statistical analysis. Shapiro-Wilk test, Mann-Whitney-Wilcoxon u test, Spearman rank correlation coefficient and stepwise multiple regression: p values of 0.05 or less were considered as significant. RESULTS: Taking all women into account (n=86) the plasma leptin level correlated directly with age (r=0.32; p<0.02), body mass (r=0.60; p<0.001), BMI (r=0.71; p<0.001) as well as inversely with estradiol (r=-0.21; p<0.05), IGF-I (r=-0.24; p<0.05), SHBG (r=-0.34; p<0.01) and DHEAS (r=-0.30; p<0.01). However only in the group B leptin/age relation remained (r=0.40; p<0.05) after the division according to BMI. In the group B the leptin /DHEAS (r=-0.40; p<0.05) and leptin/PRL (r=0.51; p<0.05) links were also present. In the group C the leptin/SHGB relation (r=-0.56; p<0.02) only remained and an association between insulin and leptin was found (r=0.48; p<0.05). The body mass and BMI relation to age were again present only in all 86 women (r=0.30; p<0.002: r=0.36; p<0.001 resp.). Having split the women into groups, these links either disappeared or became inverse (rC=-0.39; p<0.05). Taking into consideration age/leptin relation in all women, the division according to the menopausal status revealed the direct relation in premenopausal women (n=29; r=0.43; p<0.02) and a reverse one in postmenopausal women (n=38; r=-0.32; p<0.05). The plasma leptin level was the highest (p<0.001) in group C (23.2+/-10.4 microg/l) and the lowest was found in the group A (8.9+/-4.1 microg/l). That corresponded with the differences in mean body mass index and mean body mass. The stepwise multiple regression revealed that body mass index accounted for 31% (p<0.001) and plasma SHBG level accounted for 17.7% (p<0.02) of plasma leptin variance in all women. In the group A body mass and age together accounted for 61% (p<0.01) and estradiol alone accounted for 44% (p<0.02) of plasma leptin variance. In the group B insulin alone accounted for 39% (p<0.05) and together with testosterone accounted for 46% (p<0.05) of plasma leptin variance. Finally in obese women none of the evaluated parameters significantly accounted for leptin variance. CONCLUSION: The results presented in this paper confirmed the strong influence of body fat mass on serum leptin concentration. However insulin, SHBG, sex steroids as well as age may also exert secondary influence on plasma leptin level in certain groups of women.     

Remnant-like particle cholesterol and triglyceride levels of hypertriglyceridemic patients in the fed and fasted state

Potentially atherogenic triglyceride-rich lipoprotein (TRL) remnants can be isolated and quantitated as remnant-like particles (RLP), using an immunoaffinity gel containing specific anti-human apolipoprotein A-I (apoA-I) and apoB-100 monoclonal antibodies. The aim of the present study was to determine the relationship between postprandial changes in RLP levels and changes in total serum triglyceride (TG) in patients with different forms of hypertriglyceridemia (HTG). Three groups of patients were selected, having similarly elevated serum TG levels: a) HTG with TRL remnant accumulation (i.e., type III patients, n = 15, TG: 3.8 +/- 0.2 mm), b) HTG with increased LDL (i.e., type IIb patients, n = 15, TG: 3.7 +/- 0.2 mm), and c) HTG without evidence of remnant or LDL accumulation (i.e., type IV patients, n = 15, TG: 3.9 +/- 0.3 mm). Ingestion of a 45-g fat meal caused a significant increase in serum TG (30;-50%) in all patients. Mean serum TG levels of the three groups were not significantly different at 4 or 6 h after the meal. RLP cholesterol (C) and TG levels increased after the meal in all patients, but these postprandial increases were also not significantly different among groups. Type III patients had significantly higher (P < 0.01) levels of RLP-C and RLP-apoE in the fasted and fed state, and also had significantly higher RLP-C-to-serum TG ratios (P < 0.001) compared with the other groups. These results indicate that 1) RLP-C and RLP-TG levels are significantly increased in the fed versus fasted state in patients with elevated fasting TG levels; 2) patients with different forms of HTG, but similar TG levels, have similar postprandial increases in RLP-C and RLP-TG; and 3) type III patients have significantly elevated levels of RLP-C and RLP-apoE in both the fed and fasted state.     

Sequential microultracentrifugation of lipoproteins in 100 microliters of serum

A method is described for sequential separation of high density, very low density, and low density lipoproteins (HDL, VLDL, and LDL, respectively) from 100 microliters of serum, using an air-driven ultracentrifuge (Airfuge, Beckman). Cesium chloride was used for density adjustment. Precision-within-series (coefficient or variation) depended on the cholesterol concentration in the lipoprotein fractions, greater than 1 mmol/l, less than 2.3%. Recovery within-series was nearly 100%. The results (mmol/l) correlate well with those from an electrophoretic-enzymatic procedure (alpha-HDL: 1.49 +/- 0.34 vs. 1.48 +/- 0.33, r = 0.949; pre-beta-VLDL: 0.58 +/- 0.42 vs. 0.59 +/- 0.45, r = 0.975; beta-LDL: 3.11 +/- 0.93 vs. 3.07 +/- 0.88, r = 0.990; n = 48). Recovery of lipoprotein cholesterol from this group was 99.2 +/- 4.2%. A combination of ultracentrifugation with high-performance thin-layer chromatography for determination of lipoprotein-lipid profiles was achieved with recoveries of 98-101%, as evaluated from a group of healthy men (n = 31) and women (n = 38). The entire procedure is, therefore, suitable for compositional studies on lipoproteins from small serum samples. In particular, capillary serum from children of all ages, even from premature neonates, is quite adequate.     

Increased plasma apoA-IV level is a marker of abnormal postprandial lipemia: a study in normoponderal and obese subjects.

Plasma apolipoprotein A-IV (apoA-IV) levels are found elevated in hypertriglyceridemic patients. However, the relationship between plasma apoA-IV level and postprandial lipemia is not well known and remains to be elucidated. Thus, our objective was to study the relationship between plasma apoA-IV and postprandial TG after an oral fat load test (OFLT). Plasma apoA-IV was measured at fast and during an OFLT in 16 normotriglyceridemic, normoglucose-tolerant android obese subjects (BMI = 34.6 +/- 2.9 kg/m(2)) and 30 normal weight controls (BMI = 22.2 +/- 2.3 kg/m(2)). In spite of not statistically different fasting plasma TG levels in controls and obese patients, the former group showed an altered TG response after OFLT, featuring increased nonchylomicron TG area under the curve (AUC) compared with controls (516 +/- 138 vs. 426 +/- 119 mmol/l x min, P < 0.05). As compared to controls, obese patients showed increased apoA-IV levels both at fast (138.5 +/- 22.4 vs. 124.0 +/- 22.8 mg/l, P < 0.05) and during the OFLT (apoA-IV AUC: 79,833 +/- 14,281 vs. 68,176 +/- 17,463 mg/l x min, P < 0.05). Among the whole population studied, as among the control and obese subgroups, fasting plasma apoA-IV correlated significantly with AUC of plasma TG (r = 0.60, P < 0.001), AUC of chymomicron TG (r = 0.45, P < 0.01), and AUC of nonchylomicron TG (r = 0.62, P < 0.001). In the multivariate analysis, fasting apoA-IV level constituted an independent and highly significant determinant of AUC of plasma TG, AUC of chymomicron TG, AUC of nonchylomicron TG, and incremental AUC of plasma TG. In conclusion, we show a strong link between fasting apoA-IV and postprandial TG metabolism. Plasma fasting apoA-IV is shown to be a good marker of TG response after an OFLT, providing additional information on post-load TG response in conjunction with other known factors such as fasting TGs.     

Lipoproteins status in professional football players after period of vacation and one month after a new intensive training program

Plasmatic lipoproteins were evaluated in a group of 11 professional football-players after a 3-week rest, and one month later, after an intensive training (characterized by a succession of aerobic and anaerobic efforts), for engaging a new competition. At day 0, total cholesterol (TC = 4.4 +/- .04 mmol/l), triglycerides (TG = .6 +/- .04 mmol/l), and LDL-TC (2.54 +/- .18 mmol/l) were significantly decreased versus sex and age matched sedentary subjects (TC = 5.13 +/- .2 mmol/l, P less than .02; TG = .99 +/- . mmol/l, P less than .01; LDL-CT = 3.26 +/- .2 mmol/l, P less than .02). HDL-TC was increased (1.50 +/- .06 vs 1.30 +/- .05 mmol/l, P less than .05). The apoprotein A1 (apoA1) was higher in football-players (1.5 +/- .06 vs 1.16 g/l, P less than .001), while the apoprotein B (apoB) was lower (.6 +/- .03 vs .88 +/- .04 g/l, P less than .001). Even after 3 weeks of rest, the football-players lipoproteins were still identical to aerobic elite-athletes. At day +30, after a daily training involving 2 anaerobic sequences, the maximal aerobic capacity was increased by 21%, without any change in nutritional, plasmatic and hepatic status. Weight was diminished (-0.8 kg, P less than 0.05). TC (4.14 +/- .2 mmol/l), TG less than .64 +/- .08 mmol/l), LDL-TC (3.37 +/- .17 mmol/l), apo B (.64 +/- .05 g/l) were unchanged. HDL-CT fell to controls values while apoA1 increased (1.66 +/- .06 mmol/l, P less than .001). Thus, HDL-CT/apoA1 ratio (indicating the TC content of HDL) was decreased, whereas apoB/apoA1 ratio was unchanged. The decrease of TC content of HDL was not related to dietary change nor to weight decrease. As TG were stable, the lipoprotein lipase activity could not be modified.(ABSTRACT TRUNCATED AT 250 WORDS)     

Sex difference in the effect of obesity on 24-hour mean serum gonadotropin levels.

To determine the effect of obesity on serum gonadotropin levels and any possible sex difference in the effect, we measured the 24-hour mean serum follicle-stimulating hormone (FSH) and luteinizing hormone (LH) concentrations in 62 healthy men with Body Mass Index (BMI) ranging from 20 - 94 and 61 healthy, regularly cycling women with BMIs ranging from 19 - 76. We also measured free testosterone (T) and estradiol (E2) in these subjects. There was a significant negative correlation between serum FSH and BMI in men: FSH(IU/L) = 49.9 x BMI -0.567; r = - 0.376, p = 0.0026; but a significant positive correlation between serum FSH and BMI in women: FSH(IU/L) =7.66 +/- 0.071 x BMI; r = 0.302, p = 0.018. Serum LH was weight-invariant in both sexes. In men, free T was negatively correlated with BMI: Free T (nmol/L) = 0.74 - 0.0068 x BMI; r = 0.585, p = 0.0381; and free E2 was positively correlated with BMI: Free E2 (pmol/L) = - 1.03 +/- 0.057 x BMI; r = 0.50, p = 0.0014. In obese women as a group, free T was higher than in lean women (33 +/- 6.8 S.E.M. vs. 17.4 +/- 2.0 pmol/L; p < 0.0001), and free E2 was also higher than in lean women: (6.90 +/- 0.80 vs. 4.84 +/- 0.55 pmol/L; p = 0.046). Of the many cases of hypothalamic-pituitary hormonal dysregulation that have been reported in obesity, none has been studied for sex differences. Our results mandate that possible sex differences be investigated in all cases of dysregulation.     

Atherogenic lipoprotein profile in families with and without history of early myocardial infarction

In this study we compared several parameters characterizing differences in the lipoprotein profile between members of families with a positive or negative family history of coronary artery disease (CAD). In addition to regular parameters such as the body mass index (BMI), total plasma cholesterol (TC), low density (LDL-C) and high density (HDL-C) cholesterol and triglycerides (TG) we estimated the fractional esterification rate of cholesterol in apoB lipoprotein-depleted plasma (FER(HDL)) which reflects HDL and LDL particle size distribution. A prevalence of smaller particles for the atherogenic profile of plasma lipoproteins is typical. Log (TG/HDL-C) as a newly established atherogenic index of plasma (AIP) was calculated and correlated with other parameters. The cohort in the study consisted of 29 young (< 54 years old) male survivors of myocardial infarction (MI), their spouses and at least one offspring (MI group; n=116). The control group consisted of 29 apparently healthy men with no family history of premature CAD in three generations, their spouses and at least one offspring (control group; n=124). MI families had significantly higher BMI than the controls, with the exception of spouses. Plasma TC did not significantly differ between MI and the controls. MI spouses had significantly higher TG. Higher LDL-C had MI survivors only, while lower HDL-C had both MI survivors and their spouses compared to the controls. FER(HDL) was significantly higher in all the MI subgroups (probands 25.85+/-1.22, spouses 21.55+/-2.05, their daughters 16.93+/-1.18 and sons 19.05+/-1.33 %/h) compared to their respective controls (men 20.80+/-1.52, spouses 14.70+/-0.98, daughters 13.23+/-0.74, sons 15.7+/-0.76 %/h, p<0.01 to p<0.05). Log(TG/HDL-C) ranged from negative values in control subjects to positive values in MI probands. High correlation between FER(HDL) and Log (TG/HDL-C) (r=0.80, p<0.0001) confirmed close interactions among TG, HDL-C and cholesterol esterification rate. The finding of significantly higher values of FER(HDL) and Log (TG/HDL-C) indicate higher incidence of atherogenic lipoprotein phenotype in members of MI families. The possibility that, in addition to genetic factors, a shared environment likely contributes to the familial aggregation of CAD risk factors is supported by a significant correlation of the FER(HDL) values within spousal pairs (control pairs: r=0.51 p<0.01, MI pairs: r=0.41 p<0.05).     

Measurement of fasting serum apoB-48 levels in normolipidemic and hyperlipidemic subjects by ELISA

The present study was designed to evaluate the metabolism of chylomicron and chylomicron remnants by measuring serum apolipoprotein B-48 (apoB-48) levels in 335 normolipidemic and 253 hyperlipidemic subjects using a novel ELISA system. The distribution of fasting serum apoB-48 levels in normolipidemic subjects varied widely, ranging from <1 to >24 microgram/ml (mean, 5.2 +/- 3.8 microgram/ml; median, 3.9 microgram/ml). Serum apoB-48 levels correlated with serum triglyceride (TG) concentrations (r = 0.45, P < 0.001), but not with total cholesterol levels. Serum apoB-48 levels were 7 to 18 times higher in patients with Type I, Type V, and Type III hyperlipidemia, and only slightly higher in patients with Type IIa, Type IIb, and Type IV hyperlipidemia, compared with normolipidemic subjects. The calculated apoB-48/TG ratio was elevated only in patients with dysbetalipoproteinemia (apoE2/2 phenotype). In normolipidemic subjects, oral fat loading resulted in about 2-fold increase in serum apoB-48 levels, with a peak level recorded at 3-4 h postloading, and then returned to the baseline level within 6 h. On the other hand, in patients with dysbetalipoproteinemia, serum apoB-48 levels did not change considerably. Our results indicate that serum apoB-48 is a very useful parameter for evaluating lipoprotein metabolism in exogenous pathways.     

Omega-3 fatty acid supplementation accelerates chylomicron triglyceride clearance

Omega-3 fatty acids (FAs) reduce postprandial triacylglycerol (TG) concentrations. This study was undertaken to determine whether this effect was due to reduced production or increased clearance of chylomicrons. Healthy subjects (n = 33) began with a 4-week, olive oil placebo (4 g/d) run-in period. After a 4-week wash-out period, subjects were randomized to supplementation with 4 g/d of ethyl esters of either safflower oil (SAF), eicosapentaenoic acid (EPA), or docosahexaenoic acid (DHA) for 4 weeks. Results for EPA and DHA were similar, and therefore the data were combined into one omega-3 FA group. Omega-3 FA supplementation reduced the postprandial TG and apolipoprotein B (apo B)-48 and apoB-100 concentrations by 16% (P = 0.08), 28% (P < 0.001), and 24% (P < 0.01), respectively. Chylomicron TG half-lives in the fed state were reduced after omega-3 FA treatment (6.0 +/- 0.5 vs. 5.1 +/- 0.4 min; P < 0.05), but not after SAF (6.9 +/- 0.7 vs. 7.1 +/- 0.7 min). Omega-3 FA supplementation decreased chylomicron particle sizes (mean diameter; 293 +/- 44 vs. 175 +/- 25 nm; P < 0.01) and increased preheparin lipoprotein lipase (LPL; 0.6 +/- 0.1 vs. 0.9 +/- 0.1 micromol/h/ml; P < 0.05) activity during the fed state, but had no effect on postheparin LPL or hepatic lipase activities. The results suggest that omega-3 FA supplementation accelerates chylomicron TG clearance by increasing LPL activity, and that EPA and DHA are equally effective.     

Sex differences in abdominal, gluteal, and thigh LPL activity

Lipoprotein lipase (LPL) activity is necessary for adipocytes to take up triglycerides from the circulation, and regional differences in LPL activity could help determine regional fat storage. LPL activity has been reported to increase as a function of fat cell size, but this issue has not been extensively evaluated in different depots comparing sexes. Our objective was to determine whether sex alters the relationship between LPL activity and fat cell size. Subcutaneous adipose tissue biopsies were taken from the abdomen and thigh after an overnight fast and 1 h after a meal in 65 females (BMI 25.4 +/- 0.8, means +/- SE) and 41 males (BMI 23.7 +/- 0.3); gluteal adipose samples were obtained in 47 of the females and 27 of the males. Fat cell size was greater in females than males in thigh (P < 0.005) and gluteal (P < 0.05) regions but not in the abdomen. There was a relationship between fasting LPL activity/fat cell and fat cell size in females (abdomen r2 = 0.52, P < 0.0001; gluteal r2 = 0.23, P < 0.005; thigh r2 = 0.19, P < 0.005). In males, this relationship was seen only in the abdomen (r2 = 0.51, P < 0.0001) and thigh (r2 = 0.17, P < 0.05). Males and females had a significantly different relationship in the thigh only in the fasted state. Similar results were found in the fed state, although the strength of the relationship decreased in the abdominal regions for females only. This suggests fundamental differences in the regulation of triglyceride uptake between males and females and adipose regions.     

Salivary cortisol in low dose (1 microg) ACTH test in healthy women: comparison with serum cortisol

To date, a single report has appeared on the use of salivary cortisol for adrenal function testing with a low dose ACTH, although 1 microg has become preferred as a more physiological stimulus than the commonly used 250 microg ACTH test. Our present study was aimed to obtain physiological data on changes of free salivary cortisol after 1 microg ACTH stimulation. This approach was compared with the common method based on the changes of total serum cortisol. Intravenous, low-dose ACTH test was performed in 15 healthy women (aged 22-40 years) with normal body weight, not using hormonal contraceptives, in the follicular phase of the menstrual cycle. Blood and saliva for determination of cortisol were collected before ACTH administration and 30 and 60 min after ACTH administration. Basal concentration of salivary cortisol (mean +/- S.E.M., 15.9+/-1.96 nmol/l) increased after 1 microg ACTH to 29.1+/-2.01 nmol/l after 30 min, and to 27.4+/-2.15 nmol/l after 60 min. The differences between basal and stimulated values were highly significant (p<0.0001). The values of salivary cortisol displayed very little interindividual variability (p<0.04) in contrast to total serum cortisol values (p<0.0001) A comparison of areas under the curve (AUC) related to initial values indicated significantly higher AUC values for salivary cortisol than for total serum cortisol (1.89+/-0.88 vs. 1.22+/-0.19, p<0.01). Correlation analysis of serum and salivary cortisol levels showed a borderline relationship between basal levels (r=0.5183, p=0.0525); correlations after stimulation were not significant. Low-dose ACTH administration appeared as a sufficient stimulus for increasing salivary cortisol to a range considered as a normal adrenal functional reserve.     

Serum ghrelin levels in obese patients: the relationship to serum leptin levels and soluble leptin receptors levels

Ghrelin is a new endogenous ligand for the growth hormone secretagogue receptor. It activates the release of growth hormone from the pituitary and it also participates in the regulation of energy homeostasis. The aim of the study was to characterize changes in serum ghrelin levels in obese subjects and their relationship to the serum levels of leptin and soluble leptin receptor. Eight obese patients (6 women and 2 men) with body mass index (BMI) 40.3+/-13.4 kg.m(-2) and eight healthy controls (5 women and 3 men) with BMI 22.7+/-1.3 kg.m(-2) were examined. The ghrelin serum levels (165.0+/-58.1 vs. 343.37+/-81.96; p<0.001) and soluble leptin receptor serum levels (7.25+/-3.44 vs. 21.80+/-4.99; p<0.0001) were significantly lower in obese patients. The leptin serum levels (23.45+/-12.90 vs. 6.41+/-2.96; p<0.005) were significantly higher compared to the lean subject group. In both measured groups the levels of serum leptin significantly positively correlated with BMI. We proved a significantly lower serum ghrelin levels in the group of obese patients in comparison with the control group.     

Effects of a combination of recombinant human growth hormone with metformin on glucose metabolism and body composition in patients with metabolic syndrome.

Abdominal obesity and insulin resistance are central findings in metabolic syndrome. Since treatment with recombinant human growth hormone (rhGH) can reduce body fat mass in patients with organic GH deficiency, rhGH therapy may also have favourable effects on patients with metabolic syndrome. However, due to the highly increased risk for type 2 diabetes in these patients, strategies are needed to reduce the antagonistic effect of rhGH against insulin. We conducted a 18-month randomised, double-blind, placebo-controlled study to assess the effect of rhGH in combination with metformin (Met) in patients with metabolic syndrome. 25 obese men (55 +/- 6 years, BMI 33.4 +/- 2.9 kg/m (2)) with mildly elevated fasting plasma glucose (FPG) levels at screening (6.1-8.0 mmol/l) were included. All patients received metformin (850 mg twice daily) either alone or in combination with rhGH (daily dose 9.5 microg/kg body weight). An oGTT was performed at baseline, after 6 weeks, and after 3, 6, 12, and 18 months of therapy. Glucose disposal rate (GDR) was measured by euglycemic hyperinsulinemic clamp at 0 and 18 months and body composition was measured by DEXA every 6 months. In the Met + GH group, IGF-I increased from 146 +/- 56 microg/l to 373 +/- 111 microg/l (mean +/- SD) after 3 months and remained stable after that. BMI did not change significantly in either group during the study. Total body fat decreased by -4.3 +/- 5.4 kg in the Met + GH group and by -2.7 +/- 2.9 kg in the Met + Placebo group (differences between the two groups: p = n. s.). Waist circumference decreased in both groups (Met + GH: 118 +/- 8 cm at baseline, 112 +/- 10 cm after 18 months; Met + Placebo: 114 +/- 7 cm vs. 109 +/- 8 cm; differences between the two groups: p = 0.096). In the Met + GH group, FPG increased significantly after 6 months (5.9 +/- 0.7 vs. 6.7 +/- 0.4 mmol/l; p = 0.005), but subsequently decreased to baseline levels (18 months: 5.8 +/- 0.2 mmol/l). FPG remained stable in the Met + Placebo group until 12 months had elapsed, and then slightly decreased (baseline: 6.2 +/- 0.3, 18 months: 5.5 +/- 0.6 mmol/l, p = 0.02). No significant changes were seen in either group regarding glucose and insulin AUC during oGTT or HbA (1c) levels. GDR at 18 months increased by 20 +/- 39% in Met + GH-group and decreased by -11 +/- 25% in the Met + Placebo group (differences between the two groups: p = 0.07). In conclusion, treatment of patients with metabolic syndrome and elevated FPG levels did not cause sustained negative effects on glucose metabolism or insulin sensitivity if given in combination with metformin. However, since our data did not show significant differences between the two treatment groups with respect to body composition or lipid metabolism, future studies including larger numbers of patients will have to clarify whether the positive effects of rhGH on cardiovascular risk factors that have been shown in patients with GH deficiency are also present in patients with metabolic syndrome, and are additive to the effects of metformin.     

Reference ranges of copper and zinc and the prevalence of their deficiencies in an Arab population aged 15-80 years

Serum concentrations of copper and zinc were measured by flame atomic absorption spectrophotometry in 560 Kuwaitis aged from 15 to 80 yr who were in apparent good health to establish reference ranges and determine the prevalence of the deficiency of the trace metals. Zinc/copper ratios were derived by calculation. Because the mean +/- SD (microM) for copper in females (24.9 +/- 7) was significantly higher (p<0.0001) than in males (21.0 +/- 5.8) and vice versa for zinc (17.0 +/- 3.5 [males] vs 15.5 +/- 3.4 [females]) and zinc/copper ratios (0.87 +/- 0.28 [males] vs 0.67 +/- 0.27 [females]), gender-specific reference ranges were established in addition to reference ranges for the total population. The reference range for zinc was closer to those reported for other populations than was copper. Body mass index (BMI) and copper values were lower and the zinc/copper ratio was higher in the young (15-24 yr) compared to the older subjects. Copper concentrations were positively associated with BMI values (r=0.302, p<0.0001). Smokers had significantly lower (p=0.011) BMI than nonsmokers. The prevalence of copper and zinc deficiency, 0.36% and 0.53%, respectively, was low. Generally, the values for serum copper and zinc obtained for the Kuwaiti population studied suggest adequate dietary intake of the trace metals.     

Quantification of apolipoprotein D in human urine by zone immunoelectrophoresis assay: a methodological and clinical study.

A zone immunoelectrophoresis assay (ZIA) has been developed for the quantification of apolipoprotein D (apo D) in unconcentrated native human urine. A standard curve, linear between 1 and 8 mg apo D/l was obtained with ZIA. The relative coefficients of variation for this method were 5-9% (n = 15 x 6) with a mean +/- SD of 7 +/- 1.4% and below 11% (n = 6 x 15) for within-run and between-run reproducibility, respectively. Equal amounts of apo D in unconcentrated and diluted urines, in serum and of the purified protein produced the same zone migration distances indicating parallelism between the immunologic reactions of apo D in different sample matrixes. Storage experiments with normal urines demonstrated good stability of apo D in both acidic and alkalinized urine over at least 2 days at +5 degrees C and during several days at -20 degrees C to -40 degrees C. Using ZIA, urine samples from 50 normal healthy men aged 23-65 years were analyzed for apo D. Mean and SD were: 2.8 +/- 2.1 mg/l, 2.6 +/- 1.8 micrograms/min and 0.24 +/- 0.13 mg/mmol for concentration, rate of excretion and mass/creatinine concentration, respectively.     

Direct assessment of muscle glycogen storage after mixed meals in normal and type 2 diabetic subjects

To understand the day-to-day pathophysiology of impaired muscle glycogen storage in type 2 diabetes, glycogen concentrations were measured before and after the consumption of sequential mixed meals (breakfast: 190.5 g carbohydrate, 41.0 g fat, 28.8 g protein, 1253 kcal; lunch: 203.3 g carbohydrate, 48.1 g fat, 44.0 g protein, 1497.5 kcal) by use of natural abundance (13)C magnetic resonance spectroscopy. Subjects with diet-controlled type 2 diabetes (n = 9) and age- and body mass index-matched nondiabetic controls (n = 9) were studied. Mean fasting gastrocnemius glycogen concentration was significantly lower in the diabetic group (57.1 +/- 3.6 vs. 68.9 +/- 4.1 mmol/l; P < 0.05). After the first meal, mean glycogen concentration in the control group rose significantly from basal (97.1 +/- 7.0 mmol/l at 240 min; P = 0.005). After the second meal, the high level of muscle glycogen concentration in the control group was maintained, with a further rise to 108.0 +/- 11.6 mmol/l by 480 min. In the diabetic group, the postprandial rise was markedly lower than that of the control group (65.9 +/- 5.2 mmol/l at 240 min, P < 0.005, and 70.8 +/- 6.7 mmol/l at 480 min, P = 0.01) despite considerably greater serum insulin levels (752.0 +/- 109.0 vs. 372.3 +/- 78.2 pmol/l at 300 min, P = 0.013). This was associated with a significantly greater postprandial hyperglycemia (10.8 +/- 1.3 vs. 5.3 +/- 0.2 mmol/l at 240 min, P < 0.005). Basal muscle glycogen concentration correlated inversely with fasting blood glucose (r = -0.55, P < 0.02) and fasting serum insulin (r = -0.57, P < 0.02). The increment in muscle glycogen correlated with initial increment in serum insulin only in the control group (r = 0.87, P < 0.002). This study quantitates for the first time the subnormal basal muscle glycogen concentration and the inadequate glycogen storage after meals in type 2 diabetes.     

Relations between particle size of HDL and LDL lipoproteins and cholesterol esterification rate

Particle size of low density (LDL) and high density (HDL) lipoproteins and cholesterol esterification rate in HDL plasma (FER(HDL)) are important independent predictors of coronary artery diseases (CAD). In this study we assessed the interrelations between these indicators and routinely examined plasma lipid parameters and plasma glucose concentrations. In 141 men, healthy volunteers, we examined plasma total cholesterol (TC), triglycerides (TG), HDL and LDL cholesterol (HDL-C, LDL-C) and HDL unesterified cholesterol (HDL-UC). Particle size distribution in HDL and LDL was assessed by gradient gel electrophoresis and FER(HDL) was estimated by radioassay. An effect of particle size and FER(HDL) on atherogenic indexes as the Log(TG/HDL-C) and TC/HDL-C was evaluated. Subjects in the study had plasma concentrations (mean +/- S.D.) of TC 5.2+/-0.9 mmol/l, HDL-C 1.2+/-0.3 mmol/l, TG 2.1+/-1.7 mmol/l, glucose 5+/-0.8 mmol/l. Relative concentration of HDL(2b) was 17.6+/-11.5 % and 14.6+/-11.8 % of HDL(3b,c). The mean diameter of LDL particles was 25.8+/-1.5 nm. The increase in FER(HDL) significantly correlated with the decrease in HDL(2b) and LDL particle size (r = -0.537 and -0.583, respectively, P<0.01) and the increase in HDL(3b,c) (0.473, P<0.01). Strong interrelations among TG and HDL-C or HDL-UC and FER(HDL) and particle size were found, but TC or LDL-C did not have such an effect. Atherogenic indexes Log(TG/HDL-C) and TC/HDL-C correlated with FER(HDL) (0.827 and 0.750, respectively, P<0.0001) and with HDL and LDL particle size.     

Delayed clearance of postprandial large TG-rich particles in normolipidemic carriers of LPL Asn291Ser gene variant.

The carrier frequency of Asn291Ser polymorphism of the lipoprotein lipase (LPL) gene is 4;-6% in the Western population. Heterozygotes are prone to fasting hypertriglyceridemia and low high density lipoprotein (HDL) cholesterol concentrations especially when secondary factors are superimposed on the genetic defect. We studied the LPL Asn291Ser gene variant as a modulator of postprandial lipemia in heterozygote carriers. Ten normolipidemic carriers were compared to ten control subjects, who were selected to have similar age, sex, BMI, and apolipoprotein (apo)E-phenotype. The subjects were given a lipid-rich mixed meal and their insulin sensitivity was determined by euglycemic hyperinsulinemic clamp technique. The two groups had comparable fasting triglycerides and glucose utilization rate during insulin infusion, but fasting HDL cholesterol was lower in carriers (1.25 +/- 0.05 mmol/L) than in the control subjects (1. 53 +/- 0.06 mmol/L, P = 0.005). In the postprandial state the most pronounced differences were found in the very low density lipoprotein 1 (VLDL1) fraction, where the carriers displayed higher responses of apoB-48 area under the curve (AUC), apoB-100 AUC, triglyceride AUC, and retinyl ester AUC than the control subjects. The most marked differences in apoB-48 and apoB-100 concentrations were observed late in the postprandial period (9 and 12 h), demonstrating delayed clearance of triglyceride-rich particles of both hepatic and intestinal origin. Postprandially, the carriers exhibited enrichment of triglycerides in HDL fraction. Thus, in normolipidemic carriers the LPL Asn291Ser gene variant delays postprandial triglyceride, apoB-48, apoB-100, and retinyl ester metabolism in VLDL1 fraction and alters postprandial HDL composition compared to matched non-carriers.     

Influence of lipoprotein-lipase activity on plasma triacylglycerol concentration and lipid storage in three genotypes of ducks.

The lipoprotein-lipase (LPL) hydrolyses the triacylglycerols (TG) secreted by the liver and, thus, allows the storage of lipids onto the extrahepatic tissues. The LPL activity has been studied by injection of LPL antibodies in three genotypes of ducks (Muscovy (Cairina moschat), Pekin (Anas plathyrhynchos) and Mule (hybrids of male Muscovy ducks and female Pekin ducks)) under overfeeding condition. The results show a similar weight gain between injected and control animals. A higher liver steatosis is observed in Mule ducks (616+/-18 g; 8.79% of body mass (BW)) and Muscovy ducks (514+/-13 g; 7.05% BW) compared to Pekin ducks (353+/-21 g; 5.89% BW, p<0.05). Pekin ducks showed a much marked extrahepatic fattening of abdominal and subcutaneous adipose tissues. The LPL activity was evaluated by comparing the evolution of the plasma TG concentrations after injections of saline (control animals) or injections of specific LPL-antibodies. Inhibition of LPL activity performed by intravenous injections of LPL-antibodies showed a spectacular increase in the plasma TG concentrations in the three genotypes. That increase was considerably higher in Pekin ducks (98+/-10 g/L) compared to Muscovy ducks (35+/-2 g/L, p<0.01) and Mule ducks (30+/-4 g/L, p<0.01). Those data suggest that a high export of lipids synthesized in liver and a high LPL activity occur in overfed Pekin ducks, which can favour the extrahepatic fattening to the detriment of the liver steatosis, and conversely in overfed Muscovy and Mule ducks.