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At least 19 recordsLinked to original sources
PubMed2001

Acute hyperinsulinism modulates plasma apolipoprotein B-48 triglyceride-rich lipoproteins in healthy subjects during the postprandial period.

The role of postprandial insulin in the regulation of postprandial lipid metabolism is still poorly understood. The roles of hyperinsulinemia and insulin resistance in the alteration of postprandial lipid metabolism are not clear either. To improve knowledge in this area, we submitted healthy men to acute hyperinsulinemia in two different ways. In the first study, we compared in 10 men the effects of four isolipidic test meals that induce different degrees of hyperinsulinemia on postprandial lipid metabolism. Three different carbohydrate sources were compared according to their glycemic indexes (GIs; 35, 75, and 100 for white kidney bean, spaghetti, and white bread test meals, respectively); the fourth test meal did not contain any carbohydrates. Postprandial plasma insulin levels were proportional to the GIs (maximal plasma insulin concentrations: 113 +/- 16 to 266 +/- 36 pmol/l). We found a strong positive correlation during the 6-h postprandial period between apolipoprotein (apo) B-48 plasma concentration and insulin plasma concentration (r2 = 0.70; P = 0.0001). In a second study, 5 of the 10 subjects again ingested the carbohydrate-free meal, but during a 3-h hyperinsulinemic- (550 +/- 145 pmol/l plasma insulin) euglycemic (5.5 +/- 0.8 mmol/l plasma glucose) clamp. A biphasic response was observed with markedly reduced levels of plasma apoB-48 during insulin infusion, followed by a late accumulation of plasma apoB-48 and triglycerides. Overall, the data obtained showed that portal and peripheral hyperinsulinism delays and exacerbates postprandial accumulation of intestinally derived chylomicrons in plasma and thus is involved in the regulation of apoB-48-triglyceride-rich lipoprotein metabolism, in the absence of insulin-resistance syndrome.

Acute Disease↗
PubMed2005

The influence of the glycaemic index of breakfast and lunch on substrate utilisation during the postprandial periods and subsequent exercise.

The present study investigated the effects of mixed high-carbohydrate (CHO) meals (breakfast and lunch) with different glycaemic indices (GI) on substrate metabolism during rest throughout the postprandial periods and during subsequent exercise. Nine recreationally active males completed two trials, high glycaemic index (HGI) and low glycaemic index (LGI), separated by 7 d in a randomised crossover design. In each trial, participants consumed breakfast and lunch, both of which were followed by a 3 h resting postprandial period. Following this, participants completed a 60 min run at 70 % of V O2max. The plasma glucose and serum insulin concentrations following both meals were significantly higher in the HGI trial than in the LGI trial (P<0.05). Serum insulin concentrations remained higher throughout the postprandial period following lunch in the HGI trial compared with the LGI trial (P<0.05). The total amount of fat oxidised was higher during the 3 h rest following lunch in the LGI trial than in the HGI trial (P<0.01) and subsequently CHO oxidation was lower (P<0.005). No significant differences in substrate utilisation were observed throughout the subsequent run. At 45 and 60 min, plasma glucose concentrations were higher in the LGI trial v. the HGI trial (P<0.05). The results of the present study provide further support that the GI concept can be successfully applied to mixed meals. The results also suggest that meals composed of LGI CHO may be more beneficial for maintaining a favourable metabolic milieu during the postprandial periods. Furthermore, during subsequent exercise, plasma glucose concentrations were better maintained following the LGI CHO meals.

Adult↗
PubMed1992

[Barrett's esophagus, gastroesophageal acid reflux and duodenogastric reflux during the digestive and postprandial period].

Pathologic gastroesophageal acid reflux appears to be involved in the pathogenicity of Barrett's esophagus. The possible pathogenic role of duodenogastric reflux, however, has been suggested by several studies. The aim of this prospective study was to assess the prevalence of acid or duodenogastric reflux in patients with Barrett's esophagus. Nine patients with histologically proven Barrett's esophagus (mean length: 7.7cm; range: 2-13 cm) were studied by esophageal manometry and 24 hour pHmetry. Duodenogastric reflux was measured in the interdigestive period by aspiration and during the postprandial period using an isotopic method. The results of these different investigations were compared with healthy volunteers (n = 20 to 27). Three patients had complicated Barrett's esophagus (Barrett's ulcer: n = 2, high-grade dysplasia: n = 1). The results of the different investigations showed that a) all patients had abnormal acid exposure and an esophageal motor dysfunction (decrease in lower esophageal sphincter pressure, amplitude and duration of contractions and increase in percentage of peristaltic dysfunction); b) none of the patients had any pathologic duodenogastric reflux neither in the interdigestive nor in the postprandial period. These results a) confirm the high prevalence of acid reflux in patients with Barrett's esophagus, b) show that bile or pancreatic secretions are not involved in the pathogenicity of Barrett's esophagus.

Adult↗
PubMed1996

Gastric antrectomy with selective gastric vagotomy does not influence gallbladder motility during interdigestive and postprandial periods.

Fasting gastrointestinal motility and gallbladder motility during the interdigestive state and in the postprandial period was studied in eight patients who were operated for ulcer disease with an antrectomy and selective gastric vagotomy. Nocturnal motility recording revealed all three phases of the migrating motor complex (MMC) in all but one patient, where no phase III activity was recorded. In the rest of the patients 3-10 events with phase III activity were recorded. At scintigraphy ([75Se]HCAT) a cyclic gallbladder filling and emptying in relation to the MMC cycle was found. Episodes with emptying were confined to phase II and a total of 13 episodes with a median duration of 25 min (range 10-70 min) were observed. A median of 10.7% (6.1-17.7%) of the gallbladder contents was emptied. In a control group of eight healthy young men the values were 13.5 min (9-36 min) and 6.9% (3.7-31.1%), respectively. These differences were not significant. During the postprandial period, a lag period in gallbladder emptying of median 15 min (5-20 min) was observed when food ingestion took place during phase I of the MMC. Thereafter a gradual emptying occurred with a rate of 0.95% min (0.71-1.15%/min). In a control group of healthy young males, the lag period was 13.5 min (9-22.5 min) and the emptying rate 0.61%/min (0.08-0.77%/min). When food ingestion occurred during phase II of the MMC, the lag period of gallbladder emptying in the patient group was median 0 min (0-5 min) and the emptying rate was 0.77%/min (0.33-0.86%/min). The values in the control group were 0 min (-9 to 13.5 min) and 0.76%/min (0.54-2.25%/min), respectively. These differences between the patients and controls were not significant. In conclusion, antrectomy and selective gastric vagotomy do not influence fasting gastrointestinal motility or gallbladder motility during the interdigestive state or in the postprandial period.

Aged↗
PubMed2002

Insulin resistance affects the regulation of lipoprotein lipase in the postprandial period and in an adipose tissue-specific manner.

AIMS: Insulin is a potent stimulator of adipose tissue lipoprotein lipase (LPL). Logically, the postprandial period is therefore a privileged time of the day for the regulation of LPL by insulin in this tissue. It is not clear to what extent a defect such as insulin resistance could affect this regulation and contribute to postprandial, as well as fasting, hypertriglyceridaemia. The aim of the present protocol was to study the relationship between insulin resistance and LPL in adipose tissue and in plasma, in the particular context of the postprandial period. METHODS: For this study, 26 adult nondiabetic individuals (12 women and 14 men) with a wide range of whole-body insulin-mediated glucose uptake (as assessed with an insulin suppression test) were studied. An abdominal subcutaneous fat biopsy on one occasion, and post-heparin plasma on another occasion, were obtained 4 h into a standardized meal profile administered in the fasting state. RESULTS: Postprandial triglyceride excursions (evaluated by the incremental area under the curve during the metabolic meal profile) were inversely correlated to adipose tissue LPL mRNA levels (rho = -0.43, P < 0.03) as well as to adipose tissue LPL heparin-releasable activity (rho = -0.58, P < 0.01). Steady-state plasma glucose (SSPG) concentrations during the insulin suppression test, a reflection of the degree of insulin resistance, were also negatively correlated to adipose tissue LPL mRNA (rho = -0.50, P < 0.02) and activity (rho = -0.56, P < 0.01). There was no correlation between plasma post-heparin LPL activity/mass and postprandial triglycerides nor with insulin resistance. CONCLUSION: Regulation of adipose tissue LPL is significantly affected in insulin-resistant individuals in the postprandial period. This presumed impaired effect of insulin on LPL postprandially could be an important contributor to the atherogenic dyslipidaemia described in insulin resistance syndrome.

Adipose Tissue↗
PubMed1978

[Bile lipid composition of cholecystectomized patients during fasting and in postprandial periods].

Fasting state, 1 and 3 hours postprandial biliary lipid periods are studied in 19 cholecystectomized gallstone patients. Methodological items togeher with the characteristics of the kind of diet: normocaloric; lipids, 15% (50% of which are obtained from animals); proteins, 25%; and carbohydrates, 60% are established. It is concluded that biliary lipids are not quantitatively modified in the subjects on established diet respect fasting, 1 and 3 hours postprandial periods, particularly pointing out that the biliary cholesterol saturation rate remains unchanged--supersaturated--for fasting state, as well as for postprandial periods. We believe that the lack of observable changes may be in relation with the characteristics of the employed diet, which is usually suggested to people suffering from cholecystopathies in Argentina.

Bile↗
PubMed1998

Adipose tissue metabolism in the postprandial period: microdialysis and arteriovenous techniques compared.

We investigated whether two different methods of studying metabolism in adipose tissue, microdialysis and the arteriovenous technique, produced comparable results during the postprandial period. Interstitial glycerol concentrations measured by microdialysis are usually used as an index of intracellular lipolysis, and it is not known whether they also reflect the intravascular action of lipoprotein lipase in the postprandial period. The two techniques were compared in 10 healthy subjects fed mixed meals. Interstitial glycerol concentrations reflected those measured in adipose tissue venous plasma. However, the calculation of the rate of glycerol release from adipose tissue using the microdialysis data differed systematically from that using arteriovenous difference measurement. The former method gave, on average, 40% lower values than the latter one. The difference is probably due to the assumptions that had to be made for the calculation of glycerol release. The two techniques have complementary places in the study of postprandial adipose tissue metabolism, with microdialysis reflecting intracellular hormone-sensitive lipase action rather than intravascular lipoprotein lipase.

Adipose Tissue↗
PubMed1992

Leucine excess under conditions of low or compensated aminoacidemia does not change skeletal muscle and whole-body protein synthesis in suckling lambs during postprandial period.

We determined the effect of a 4-h leucine infusion, leading to 15-fold elevated plasma leucine concentrations, on skeletal muscle and whole-body protein synthesis in suckling lambs during the postprandial period. The [3H]phenylalanine large dose method was validated and used to quantify the fractional rates of protein synthesis (Ks in %/d) at the end of the leucine infusion. In the first experiment leucine infusion lowered plasma amino acid concentrations but did not change the Ks, the capacity for protein synthesis (Cs, mg RNA/g protein) or the efficiency of translation [g protein synthesized/(d-g RNA)] in any muscles studied or the whole body. In the second experiment the leucine-induced decreases in plasma amino acid concentrations were compensated by the simultaneous infusion of substantial amounts of amino acids. Again leucine excess did not significantly change Ks, Cs and efficiency of protein synthesis. These results indicated that leucine excess in suckling lambs during the postprandial period lowered aminoacidemia without any change of the protein synthesis rates in skeletal muscles or the whole body.

Amino Acids↗
PubMed1998

Coordinated release of acylation stimulating protein (ASP) and triacylglycerol clearance by human adipose tissue in vivo in the postprandial period.

The objective of this study was to determine whether Acylation Stimulating Protein (ASP) is generated in vivo by human adipose tissue during the postprandial period. After a fat meal, samples from 12 subjects were obtained (up to 6 h) from an arterialized hand vein and an anterior abdominal wall vein that drains adipose tissue. Veno-arterial (V-A) gradients across the subcutaneous adipose tissue bed were calculated. The data demonstrate that ASP is produced in vivo (positive V-A gradient) With maximal production at 3-5 h postprandially. The plasma triacylglycerol (TAG) clearance was evidenced by a negative V-A gradient. It increased substantially after 3 h and remained prominent until the final time point. There was, therefore, a close temporal coordination between ASP generation and TAG clearance. In contrast, plasma insulin and non-esterified fatty acid (NEFA) had an early (1-2 h) postprandial change. Fatty acid incorporation into adipose tissue (FIAT) was calculated from V-A glycerol and non-esterified fatty acid (NEFA) differences postprandially. FIAT was negative during the first hour, implying net fat mobilization. FIAT then became increasingly positive, implying net fat deposition, and overall followed the same time course as ASP and TAG clearance. There was a direct positive correlation between total ASP production and total FIAT (r = 0.566, P < 0.05). These data demonstrate that ASP is generated in vivo by human adipocytes and that this process is accentuated postprandially, supporting the concept that ASP plays an important role in clearance of TAG from plasma and fatty acid storage in adipose tissue.

Adipose Tissue↗
PubMed2005

The impact of the timing of Humalog Mix25 injections on blood glucose fluctuations in the postprandial period in elderly patients with type 2 diabetes.

BACKGROUND: Postprandial hyperglycemia contributes to glycation of hemoglobin A1c and has been associated with cardiovascular risk in people with diabetes. We investigated the impact of injection timing of Humalog Mix25 (Mix25, known as Humalog Mix75/25 in the U.S.: 25% insulin lispro and 75% neutral protamine lispro) on glycemia and postprandial blood glucose (BG) excursions in elderly individuals MATERIAL/METHODS: Seventy-three patients aged 60 to 80 years were randomized to Mix25 (Mix25 group, 37 participants) or a continuation with maximum dose glibenclamide (control group, 36 participants). The Mix25 group was subdivided into a group of 18 patients who were injecting insulin after meals and 19 who were injecting before. RESULTS: At baseline, the absolute postprandial BG concentrations and postprandial BG excursions after breakfast were high (Mix25 group: 15.3+/-4.8 mmol/l and 3.5+/-2.7 mmol/l, respectively; controls: 15.4+/-3.9 mmol/l and 4.7+/-2.7 mmol/l, respectively). In both groups improvement was observed at the endpoint, but it was greater with Mix25 (Mix25 group: 10.3+/-3.6 mmol/l, p<0.0001 vs. baseline, p<0.003 vs. controls, and 2.0+/-2.5 mmol/l, p<0.008 vs. baseline, p=ns vs. controls; control group: 13.3+/-2.9 mmol/l, p<0.006 vs. baseline, and 4.7+/-2.7 mmol/l, p<0.006 vs. baseline). The two Mix25 subgroups had similar postprandial BG levels and BG excursions after breakfast. CONCLUSIONS: Mix25 improves postprandial BG and yields a greater effect on BG excursions compared with monotherapy with glibenclamide. The timing of Mix25 did not impact the level of BG or BG fluctuations after meals, which may be important for individuals with changing dietary pattern.

Aged↗
PubMed2005

Plasma cytokine response during the postprandial period: a potential causal process in vascular disease?

Chronic inflammation of the vascular endothelium produces endothelial dysfunction and ultimately atherogenesis. Postprandial hyperlipidaemia is an independent risk factor for cardiovascular disease. Recent studies show that the magnitude of postprandial lipaemia following a single fatty meal is negatively related to vascular function. This is associated with a transient increase in the concentrations of pro-inflammatory cytokines and soluble adhesion molecules and in pro-oxidant activity. One possible interpretation is that repeated exposure of the blood vessel wall to the activities of pro-inflammatory cytokines and pro-oxidants may damage the vascular endothelium and promote atherogenesis. Based on these results, we propose a model of a causal mechanism to explain how consumption of a fatty meal may impair vascular dysfunction.

Cardiovascular Diseases↗
PubMed2001

alpha-Dicarbonyls increase in the postprandial period and reflect the degree of hyperglycemia.

OBJECTIVE: Chronic hyperglycemia is known to increase tissue glycation and diabetic complications, but controversy exists regarding the independent role of increased postprandial glucose excursions. To address this question, we have studied the effect of postprandial glycemic excursions (PPGEs) on levels of methylglyoxal (MG) and 3-deoxyglucosone (3-DG), two highly reactive precursors of advanced glycation end products (AGEs). RESEARCH DESIGN AND METHODS: We performed 4-month crossover studies on 21 subjects with type 1 diabetes and compared the effect of premeal insulin lispro or regular insulin on PPGEs and MG/3-DG excursions. PPGE was determined after standard test meal (STMs) and by frequent postprandial glucose monitoring. HbA1c and postprandial MG and D-lactate were measured by HPLC, whereas 3-DG was determined by gas chromatography/mass spectroscopy. RESULTS: Treatment with insulin lispro resulted in a highly significant reduction in PPGEs relative to the regular insulin-treated group (P = 0.0005). However, HbA1c levels were similar in the two groups, and no relationship was observed between HbA1c and PPGE (P = 0.93). Significant postprandial increases in MG, 3-DG, and D-lactate occurred after the STM. Excursions of MG and 3-DG were highly correlated with levels of PPGE (R = 0.55, P = 0.0002 and R = 0.61, P = 0.0004; respectively), whereas a significant inverse relationship was seen between PPGE and D-lactate excursions (R = 0.40, P = 0.01). Conversely, no correlation was observed between HbAlc and postprandial MG, 3-DG, or D-lactate levels. CONCLUSIONS: Increased production of MG and 3-DG occur with greater PPGE, whereas HbA1c does not reflect these differences. Reduced PPGE also leads to increased production of D-lactate, indicating a role for increased detoxification in reducing MG levels. The higher postprandial levels of MG and 3-DG observed with greater PPGE may provide a partial explanation for the adverse effects of glycemic lability and support the value of agents that reduce glucose excursions.

Adolescent↗
PubMed2003

Selective partitioning of dietary fatty acids into the VLDL TG pool in the early postprandial period.

Circulating triacylglycerol (TG) arises mainly from dietary fat. However, little is known about the entry of dietary fat into the major TG pool, very low-density lipoprotein (VLDL) TG. We used a novel method to study the specific incorporation of dietary fatty acids into postprandial VLDL TG in humans. Eight healthy volunteers (age 25.4 +/- 2.2 years, body mass index 22.1 +/- 2.3 kg/m2) were fed a mixed meal containing 30 g fish oil and 600 mg [1-13C]palmitic acid. Chylomicrons and VLDL were separated using immunoaffinity against apolipoprotein B-100. The fatty acid composition of lipoproteins was analyzed by gas chromatography/mass spectrometry. [1-13C]palmitic acid started to appear in VLDL TG 3 h after meal intake, and a similar delay was observed for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Approximately 20% of dietary fatty acids entered the VLDL TG pool 6 h after meal intake. DHA was clearly overincorporated into this pool compared with [1-13C]palmitic acid and EPA. This seemed to depend on a marked elevation of this fatty acid in the nonesterified fatty acid pool. In summary, the contribution of dietary fatty acids to early postprandial VLDL TG is substantial. The role of DHA in VLDL TG production will require further investigation.

Adult↗
PubMed2007

Preferential uptake of dietary Fatty acids in adipose tissue and muscle in the postprandial period.

Despite consistent evidence that abnormalities of fatty acid delivery and storage underlie the metabolic defects of insulin resistance, physiological pathways by which fat is stored in adipose tissue and skeletal muscle are not clear. We used a combination of stable isotope labeling and arteriovenous difference measurements to elucidate pathways of postprandial fat deposition in adipose tissue and skeletal muscle in healthy humans. A test meal containing [U-(13)C]palmitate was combined with intravenous infusion of [(2)H(2)]palmitate to label plasma fatty acids and VLDL-triglyceride. Both dietary (chylomicron) and VLDL-triglyceride were cleared across adipose tissue and muscle, though with greater fractional extraction of the chylomicron-triglyceride. In adipose tissue there was significant uptake of plasma nonesterified fatty acids (NEFAs) in the postprandial but not the fasting state. However, this was minor in comparison with chylomicron-triglyceride fatty acids. We modeled the fate of fatty acids released by lipoprotein lipase (LPL). There was clear preferential uptake of these fatty acids compared with plasma NEFAs. In muscle, there was unexpected evidence for release of LPL-derived fatty acids into the plasma. With this integrative physiological approach, we have revealed hidden complexities in pathways of fatty acid uptake in adipose tissue and skeletal muscle.

Abdomen↗
PubMed2001

The metabolic availability of dietary triacylglycerols from two high oleic oils during the postprandial period does not depend on the amount of oleic acid ingested by healthy men.

Monounsaturated oils, virgin olive oil (VOO) and high oleic sunflower oil (HOSO) are suggested to have selective physiologic effects on humans in the fasting state. The aim of the study was to evaluate whether two oils with equal amounts of oleic acid but with different compositions of minor fatty acids and triacylglycerol molecular species (TAG) could produce different triacylglycerol-rich lipoprotein (TRL)-TAG responses in the postprandial state. Eight normolipidemic men consumed the following three meals in random order on separate occasions with 2 wk between meals: control meal, control meal plus VOO and control meal plus HOSO. Plasma total TAG and TRL-TAG were measured hourly for 7 h after ingestion. TAG and sn-2 positional fatty acids within TAG were analyzed in the TRL fraction. Plasma total TAG concentrations in response to the dietary oils did not differ. However, TRL triglyceridemia was significantly lower after VOO intake (P < 0.05). The molecular species in the TRL fraction returned toward basal levels more quickly (P < 0.05) after VOO than HOSO intake. 2-Positional fatty acid analysis demonstrated higher proportions of stearic and palmitic acids and a lower proportion of oleic acid (P < 0.05) in TRL-TAG derived from HOSO. This study shows that VOO intake results in attenuated postprandial TAG concentration and faster TRL-TAG disappearance from blood compared with HOSO, suggesting that the oleic acid content may not be the main factor affecting TAG metabolism. Minor fatty acids such as linoleic acid and the 2-positional distribution of saturated stearic and palmitic acids into the TAG molecule may be important determinants of postprandial lipemia in normolipidemic men.

Adult↗
PubMed1993

Neural modulation of canine duodenal bile acid delivery in the interdigestive and postprandial periods.

The neural modulation of gallbladder filling-emptying and duodenal delivery of canine hepatic biliary output was studied in conscious dogs using transient cold blockade or transection of the cervical vagosympathetic nerves previously isolated in skin loops on either side of the neck. Gallbladder filling-emptying was defined as the algebraic difference between a steady-state rate of hepatic secretion [established by a continuous intravenous infusion of [14C]taurocholic acid (TCA)] and the duodenal rate of delivery of [14C]TCA (measured by duodenal marker perfusion). Duodenal motility was recorded manometrically. Experiments in the fasted and fed state were performed under control conditions, during cold blockade, and after transection of the cervical vagosympathetic nerves. Under control conditions: 1) during fasting, the majority of hepatic [14C]TCA output was stored in the gallbladder during the first half of the migrating myoelectric complex (MMC). An increased rate of duodenal delivery and partial gallbladder emptying occurred before phase III of the MMC. 2) Feeding induced an immediate increase in duodenal bile acid delivery and gallbladder emptying. After cold blockade or transection: 1) partial gallbladder emptying before phase III of the MMC was abolished. 2) The immediate postprandial increase in duodenal bile acid delivery and gallbladder emptying was abolished even when the animal received a continuous duodenal infusion of the duodenal aspirate of another fed animal (to control for the effect of impaired gastric emptying after cold blockade). In addition, cold blockade significantly reduced the effect of an exogenous infusion of cholecystokinin octapeptide on gallbladder emptying. These results suggest that neurons in the canine cervical vagosympathetic nerves play a major role in the regulation of rhythmic partial emptying of the gallbladder in the interdigestive period, coordinate a cephalic phase of postprandial gallbladder emptying, and are important in mediating the effects of cholecystokinin on the gallbladder during the gastric and enteric phases of postprandial gallbladder emptying.

Animals↗