scholarly journals Meal timing, fasting and glucocorticoids interplay in serum leptin concentrations and diurnal profile

2002 ◽  
pp. 181-188 ◽  
Author(s):  
A Elimam ◽  
C Marcus
Keyword(s):  
Energy Intake ◽  
Serum Insulin ◽  
Fold Increase ◽  
The Other ◽  
Standard Meal ◽  
Blood Samples ◽  
Serum Leptin ◽  
Meal Timing ◽  
Diurnal Profile

BACKGROUND: In a previous study, we reported a 4-fold increase in serum leptin following total parenteral nutrition given after surgery. We hypothesised that the perioperative fasting and stress contributed to this, possibly mediated by increased serum insulin and cortisol. OBJECTIVE: To test the hypothesis that fasting, in combination with glucocorticoids, sensitises the leptin response to subsequent energy intake. DESIGN: Healthy volunteers were randomised into two groups, one group received dexamethasone (DEX), 0.1 mg twice daily for 3 days, while the other group served as a control. Each group was then subdivided into two feeding protocols. Protocol 1, where a standard meal was given at 0, 24, 36 and 48 h and protocol 2 where the same meal was given at 0 and 48 h. Blood samples were drawn before, as well as every other hour during the study period for determination of serum leptin, insulin, glucose and cortisol concentrations. RESULTS: In all groups serum leptin increased significantly following each meal (P<0.01). The rise in serum leptin in response to the standard meal was higher when the meal was taken in the evening (P<0.001) or following longer duration of fasting (P<0.02). In those fasting for 48 h, leptin decreased by 60% and showed no diurnal variation. DEX intake increased leptin concentrations in those fasting for short periods (P<0.02) but not for 48 h. CONCLUSIONS: Long durations of fasting sensitise the response of leptin to subsequent energy intake and abolish the DEX-induced upregulation of leptin. Meal timing is an important factor determining the leptin diurnal rhythm, but other factors must contribute since the leptin response to a standard meal taken in the evening was greater than to the same meal taken in the morning.

scholarly journals Intralipid/heparin infusion suppresses serum leptin in humans

2003 ◽  
pp. 669-676 ◽  
Author(s):  
P Garcia-Lorda ◽  
W Nash ◽  
A Roche ◽  
FX Pi-Sunyer ◽  
B Laferrere
Keyword(s):  
Serum Insulin ◽  
Suppressive Effect ◽  
Inhibitory Effect ◽  
Blood Levels ◽  
Heparin Infusion ◽  
Serum Leptin ◽  
Lipid Infusion ◽  
Lipid Ii ◽  
The Face

BACKGROUND/AIM: Our previous studies showed that administration of dexamethasone plus food increased serum leptin levels 100% more than dexamethasone alone. We hypothesized that this increase in leptin from the meal could result directly from the provision of fuel metabolites rather than from the meal-induced rise in insulin. In the current study, we tested the effect of an i.v. lipid fuel source (Intralipid 20%/heparin) that would incur only a modest increase in insulin. This study was undertaken because the role of lipid in the regulation of human leptin levels has been controversial, with differing effects reported: stimulatory, inhibitory, or no effect at all. METHODS: In order to evaluate how lipids affect serum leptin in humans, we administered the following to seven lean, healthy, fasting subjects: (i) Intralipid 20% at 0.83 ml/kg.h plus heparin (800 IE/h) infused i.v. for 7 h (LIPID), (ii) LIPID with one initial pulse of insulin (0.09 U/kg) given s.c. (LIPID+INS), (iii) LIPID with dexamethasone (2 mg i.v. push) given at the start of the infusion (LIPID+DEX), and (iv) LIPID with insulin plus dexamethasone (LIPID+INS+DEX). Control trials in another 14 subjects matched hormonal conditions but lacked the LIPID infusion. Blood levels were collected over 8 h for determination of free fatty acids (FFA), glucose, insulin, and leptin under each experimental condition. RESULTS: Over the 420 min of LIPID infusion, FFA levels rose four-fold from 0.28+/-0.05 mmol/l to 0.99+/-0.05 mmol/l. Serum leptin levels were suppressed by 10-20% in the LIPID condition as compared with control (no LIPID) between 90 min (P=0.008) and 360 min (P=0.045). LIPID+DEX did not increase leptin. A pulse of insulin (INS) increased serum insulin levels to 49.9+/-6.1 U/ml at 90 min and increased serum leptin by 21.3+/-6.6% at 480 min (P=0.054). LIPID decreased leptin in the face of this insulin-induced increase (LIPID+INS), between 360 min (P=0.017) and 420 min (P=0.003), with a 23% suppressive effect at 420 min. LIPID+DEX elevated leptin levels by 112.5+/-35.8% at 480 min (P=0.037), however, the Intralipid/heparin infusion did not blunt the rise of leptin under these conditions. CONCLUSIONS: These data showed that Intralipid/heparin: (i) are not sufficient to trigger the effect of dexamethasone on leptin, (ii) have an acute inhibitory effect on both fasting and insulin-stimulated leptin levels, and (iii) that this inhibitory effect cannot reverse the strong stimulatory effect of dexamethasone and insulin on serum leptin.

Studies of the skeleton of the sheep VIII. Studies of the effects of protein and energy intake on productivity and skeletal mineralization in the pregnant and lactating ewe

1962 ◽  
Vol 59 (1) ◽  
pp. 45-49 ◽  
Author(s):  
J. Duckworth ◽  
D. Benzie ◽  
E. Cresswell ◽  
R. Hill ◽  
A. W. Boyne
Keyword(s):  
Vitamin D ◽  
Energy Intake ◽  
The Other ◽  
Blood Samples ◽  
Bone Ash ◽  
Calcium Phosphorus ◽  
Pregnancy And Lactation ◽  
Lamb Growth ◽  
Skeletal Mineralization

1. Effects on productivity and skeletal mineralization of high as opposed to moderate levels of protein and, or, energy intake by the ewe during pregnancy and lactation in the presence of adequate calcium, phosphorus and vitamin D have been studied.2. Two experiments were undertaken. One experiment used 4½-year-old Cheviot ewes and the other used 3½- and 4½-year-old Scottish Blackface ewes. Weight records, blood samples and in vivo and flesh-free radiographs were obtained, and bone ash determinations were carried out.3. The results showed that contrary to indications from earlier experiments in this series superiority in ewe weight, lamb growth, and mineralization of the ewe skeleton did not necessarily result from raising the protein and, or, energy values of the feed above the ‘moderate’ level.4. Discrepancies between the in vivo and flesh - free radiological assessments were noted for consideration.

scholarly journals Relationship between body weight and leptin concentrations in mink dams and the birth parameters of kits

2016 ◽  
Vol 72 (12) ◽  
pp. 755-759 ◽  
Author(s):  
Monika Bryl ◽  
Hanna Bis-Wencel ◽  
Brygida Ślaska ◽  
Bożena Nowakowicz-Dębek ◽  
Zbigniew Bełkot ◽  
...  
Keyword(s):  
Body Weight ◽  
Body Condition ◽  
Scoring System ◽  
The Body ◽  
The Other ◽  
Blood Samples ◽  
Serum Leptin ◽  
Significant Difference ◽  
Analysis Of Results ◽  
The Impact

The aim of this study was to assess the impact of the leptin concentration and body weight of mink females on the birth parameters of their kits. Blood samples were collected 3 times during preparation for reproduction, 7±2 days before mating. Total leptin concentration in serum was measured using commercial RIA kits (Millipore, St. Charles, Missouri USA). Research was conducted on 20 clinically healthy scanbrown female minks (Neovison Vison) aged 2-3 years. To evaluate their body condition, the females were divided into two groups based on the BCS scoring system. In the first group, referred to as BCS 2, lean females were included, and the second group (BCS 4) consisted of obese females. In mink dams belonging to BCS 2, the average leptin values were one-fourth of those in the BCS 4 group. The results obtained indicate the influence of the body mass of minks during preparation for reproduction on serum leptin concentration. The results of the Mann-Whitney U test showed a statistically significant difference between weights and leptin concentrations in groups BCS 2 and BCS 4. Among the other traits, such differences were not found. The analysis of results obtained in the two mink groups did not reveal a clear relationship between leptin in the serum of mothers before mating and the birth parameters of their kits.

Methods compared for determining glutathione peroxidase activity in blood.

1987 ◽  
Vol 33 (4) ◽  
pp. 539-543 ◽  
Author(s):  
B Faraji ◽  
H K Kang ◽  
J L Valentine
Keyword(s):  
Glutathione Peroxidase ◽  
Peroxidase Activity ◽  
Reference Intervals ◽  
The Other ◽  
Specific Time ◽  
Glutathione Peroxidase Activity ◽  
Time Intervals ◽  
Indirect Methods ◽  
Blood Samples

Abstract We compared four methods for determination of glutathione peroxidase (EC 1.11.1.9) activity, using blood samples from 52 healthy volunteers. Two methods depended on direct assay of the amount of glutathione remaining at specific time intervals; the two indirect methods involved measuring the rate of disappearance of NADPH. We assessed the precision and reproducibility of each method. One of the indirect assays proved to be far superior to the other methods. Results of each of the methods were correlated with one another. We present the normal reference intervals for glutathione peroxidase activity for all four methods.

scholarly journals Milk removal in familiar and unfamiliar surroundings: concentrations of oxytocin, prolactin, cortisol and β–endorphin

1993 ◽  
Vol 60 (4) ◽  
pp. 449-456 ◽  
Author(s):  
Rupert M. Bruckmaier ◽  
Dieter Schams ◽  
Jürg W. Blum
Keyword(s):  
The Other ◽  
Operating Theatre ◽  
Flow Curves ◽  
Blood Samples ◽  
Milk Flow ◽  
Total Milk ◽  
Oxytocin Release ◽  
Central Inhibition ◽  
Vaginal Stimulation

SummaryEight cows were machine milked either in an operating theatre or in their familiar barn. During the experiments, milk flow curves were recorded and blood samples were taken for determination of concentrations of oxytocin, prolactin, cortisol and β–endorphin. The milking cluster was attached without udder preparation. After cessation of milk flow, air was blown into the vagina for 2 min. When milk flow had stopped again, 1 i.u. oxytocin and finally 10 i.u. oxytocin were injected to remove the remaining milk. After the start of milking, oxytocin remained basal in unfamiliar, but increased in familiar surroundings. Therefore, during normal milking only 9% of total milk was removed in unfamiliar, whereas 79% was available in familiar surroundings. In response to subsequent vaginal stimulation in the operating theatre, oxytocin increased transiently in five cows and 15–71% of the milk was removed in these animals. In the other three cows in the operating theatre, oxytocin remained basal during vaginal stimulation, and no more milk was available. After injection of 1 i.u. oxytocin, 56 and 11%, and after injection of 10 i.u. oxytocin, 13 and 8% of milk was removed in unfamiliar and familiar surroundings respectively. Concentrations of prolactin increased during the course of milking in both treatments. Premilking concentrations of cortisol and β–endorphin were elevated in unfamiliar as compared with familiar surroundings. During the course of milking, cortisol increased slightly and β–endorphin decreased in unfamiliar, whereas both hormones increased markedly during milking in familiar surroundings. We conclude that disturbed milk removal in unfamiliar surroundings is due to central inhibition of oxytocin release during normal milking and partly also to a response to vaginal stimulation. This blockade is possibly associated with elevated concentrations of β–endorphin.

scholarly journals “Breakfast like a king, lunch like a prince, and dinner like a pauper”: how do European children and adolescents eat?

2020 ◽  
Vol 79 (OCE2) ◽  
Author(s):  
Leonie Helen Bogl ◽  
Timm Intemann ◽  
Monica Hunsberger ◽  
Alfonso Siani ◽  
Stefaan De Henauw ◽  
...  
Keyword(s):  
Children And Adolescents ◽  
Energy Intake ◽  
Sleep Duration ◽  
Metabolic Health ◽  
The Other ◽  
Frequent Pattern ◽  
Z Score ◽  
Daily Energy Intake ◽  
Meal Timing ◽  
Daily Energy

AbstractChrono-nutrition is an emerging field of research that focuses on the interplay between nutrition, circadian rhythms and metabolism. Most nutritional guidelines recommend regular and frequent meals for children and adolescents throughout the day. However, preliminary research, mostly in animals suggests that eating at the “wrong” time of the day and longer eating windows (and concomitant shorter fasting periods) may relate to metabolic health. This study aimed to identify meal-timing patterns of European children and adolescents in eight European countries.We examined 1225 children and adolescents (mean age: 11.8 years, 50% boys, and 26% overweight/obese) from Belgium, Cyprus, Estonia, Germany, Hungary, Italy, Spain and Sweden enrolled in the European I.Family study (2013/2014). Information on energy intake and meal-timing patterns was derived from multiple web-based 24-hour dietary recalls (proxy-assisted for children < 12 years). We used the National Cancer Institute (NCI) method to estimate individual usual intakes. Subsequently, we applied the k-means algorithm to identify clusters for meal-timing patterns. Five variables were selected for the cluster analysis: 1) Duration between first and last meal of the day (eating window in hours), 2) Proportion of daily energy intake before 11am, 3) Proportion of daily energy intake after 5pm, 4) Number of meals per day, and 5) Pre-sleep fasting time.Three clusters, labelled “late and time-restricted”, “late and long” and “early and frequent” meal-timing patterns were identified. Similar clusters were derived when excluding energy misreporters according to Goldberg cut-offs. Children in the “early and frequent” pattern were younger, had a lower body mass index (BMI) z-score, and a longer sleep duration than children in the other two meal-timing patterns. A higher proportion of plausible energy reporters were classified into the “early and frequent” pattern than into the other two patterns. The proportion of children from Italy, Cyprus and Spain was highest in the “late and long” pattern, while the proportion of children from Belgium, Sweden, Germany and Hungary was highest in the “early and frequent” patterns, and the proportion of children from Estonia was highest in the “late and time-restricted” pattern.In conclusion, this study identified three different meal-timing patterns in children that varied by age, BMI z-score, country, misreporting status, and sleep duration. Investigations on the associations between meal timing patterns and metabolic health in this study sample are currently ongoing.

scholarly journals Serum leptin and insulin levels in lactating protein-restricted rats: implications for energy balance

2007 ◽  
Vol 97 (1) ◽  
pp. 27-34 ◽  
Author(s):  
C. L. P. Ferreira ◽  
G. M. Macêdo ◽  
M. Q. Latorraca ◽  
V. C. Arantes ◽  
R. V. Veloso ◽  
...  
Keyword(s):  
Energy Balance ◽  
Energy Expenditure ◽  
G Protein ◽  
Energy Intake ◽  
Serum Insulin ◽  
Control Diet ◽  
Protein Restriction ◽  
Metabolic Adaptation ◽  
Serum Leptin ◽  
Low Protein

The present study analysed the effect of protein restriction on serum insulin and leptin levels and their relationship with energy balance during lactation. Four groups of rats received isocaloric diets containing 170 g protein/kg or 60 g protein/kg from pregnancy until the 14th day of lactation: control non-lactating, control lactating (both fed a control diet), low-protein non-lactating and low-protein lactating. Energy intake, body composition, energy balance, serum insulin and leptin concentrations and the relationship between these hormones and several factors related to obesity were analysed. Low-protein-intake lactating rats exhibited hypoinsulinaemia, hyperleptinaemia, hypophagia and decreased energy expenditure compared with control lactating rats. The protein level in the carcasses was lower in the low-protein lactating group than in the control lactating group, resulting in a higher fat content in the first group compared with the latter. Body fat correlated inversely with serum insulin and positively with serum leptin level. There was a significant negative correlation between serum leptin and energy intake, and a positive relationship between energy intake and serum insulin level in lactating rats and in the combined data from both groups. Energy expenditure was correlated positively with serum insulin and negatively with serum leptin in lactating rats and when data from control non-lactating and lactating rats were pooled. Lactating rats submitted to protein restriction, compared with lactating control rats, showed that maternal reserves were preserved owing to less severe negative energy balance. This metabolic adaptation was obtained, at least in part, by the hypoinsulinaemia that resulted in increased insulin sensitivity favouring enhanced fat deposition, hyperleptinaemia and hypophagia.

Determination of the lattice translation across {110} APBs in GaAs

1988 ◽  
Vol 46 ◽  
pp. 600-601
Author(s):  
D.R. Rasmussen ◽  
N.-H. Cho ◽  
C.B. Carter
Keyword(s):  
Grain Boundaries ◽  
Lower Energy ◽  
Antiphase Boundary ◽  
The Other ◽  
Boundary Structure ◽  
Interface Plane ◽  
Inversion Symmetry ◽  
High Angle ◽  
Equilibrium Distance

Domains in GaAs can exist which are related to one another by the inversion symmetry, i.e., the sites of gallium and arsenic in one domain are interchanged in the other domain. The boundary between these two different domains is known as an antiphase boundary [1], In the terminology used to describe grain boundaries, the grains on either side of this boundary can be regarded as being Σ=1-related. For the {110} interface plane, in particular, there are equal numbers of GaGa and As-As anti-site bonds across the interface. The equilibrium distance between two atoms of the same kind crossing the boundary is expected to be different from the length of normal GaAs bonds in the bulk. Therefore, the relative position of each grain on either side of an APB may be translated such that the boundary can have a lower energy situation. This translation does not affect the perfect Σ=1 coincidence site relationship. Such a lattice translation is expected for all high-angle grain boundaries as a way of relaxation of the boundary structure.

Determination of the Burgers vector of a dislocation in a Fe-Mn alloy by weak-beam image in HVEM

1978 ◽  
Vol 36 (1) ◽  
pp. 330-331
Author(s):  
Y. Ishida ◽  
H. Ishida ◽  
K. Kohra ◽  
H. Ichinose
Keyword(s):  
High Order ◽  
Simulation Technique ◽  
The Other ◽  
Image Simulation ◽  
Diffraction Vector ◽  
Burgers Vector ◽  
Weak Beam ◽  
Beam Image ◽  
Edge Component

IntroductionA simple and accurate technique to determine the Burgers vector of a dislocation has become feasible with the advent of HVEM. The conventional image vanishing technique(1) using Bragg conditions with the diffraction vector perpendicular to the Burgers vector suffers from various drawbacks; The dislocation image appears even when the g.b = 0 criterion is satisfied, if the edge component of the dislocation is large. On the other hand, the image disappears for certain high order diffractions even when g.b ≠ 0. Furthermore, the determination of the magnitude of the Burgers vector is not easy with the criterion. Recent image simulation technique is free from the ambiguities but require too many parameters for the computation. The weak-beam “fringe counting” technique investigated in the present study is immune from the problems. Even the magnitude of the Burgers vector is determined from the number of the terminating thickness fringes at the exit of the dislocation in wedge shaped foil surfaces.

Procedures for the Quantitative Determination of Autoprothrombin C

1962 ◽  
Vol 08 (03) ◽  
pp. 434-441 ◽  
Author(s):  
Edmond R Cole ◽  
Ewa Marciniak ◽  
Walter H Seegers
Keyword(s):  
Quantitative Determination ◽  
Plasma Sample ◽  
Quantitative Measure ◽  
The Other ◽  
Clotting Time ◽  
Bovine Plasma ◽  
Autoprothrombin C

SummaryTwo quantitative procedures for autoprothrombin C are described. In one of these purified prothrombin is used as a substrate, and the activity of autoprothrombin C can be measured even if thrombin is in the preparation. In this procedure a reaction mixture is used wherein the thrombin titer which develops in 20 minutes is proportional to the autoprothrombin C in the reaction mixture. A unit is defined as the amount which will generate 70 units of thrombin in the standardized reaction mixture. In the other method thrombin interferes with the result, because a standard bovine plasma sample is recalcified and the clotting time is noted. Autoprothrombin C shortens the clotting time, and the extent of this is a quantitative measure of autoprothrombin C activity.

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