The effect of a weight-reducing diet on the nitrogen metabolism of obese adolescents

1988 ◽  
Vol 66 (11) ◽  
pp. 1469-1474 ◽  
Author(s):  
P. B. Pencharz ◽  
R. Clarke ◽  
E. H. Archibald ◽  
N. Vaisman

Rates of whole body amino nitrogen flux were measured in 16 obese adolescents undergoing weight reduction with a high protein low energy diet. The subjects received approximately 2.5 g of animal protein per day per kilogram ideal body weight and maintained nitrogen balance throughout the 18 days on the diet. Flux rates were calculated separately from the cumulative excretion of 15N in urinary ammonia and urea following the administration of a single dose of [15N]glycine. The pattern of 15N label appearance in urinary ammonia and urea nitrogen was followed for 72 h after the administration of [15N]glycine. Significant amounts of label continued to be excreted in both urinary ammonia and nitrogen for 36–48 h after label administration. The weight-reducing diet accelerated 15N cumulative excretion in urinary urea, but not in ammonia nitrogen compared with the control diet. Whole body nitrogen flux rates increased rapidly and significantly on the diet. Using the urea end product, this increase was evident on the 4th diet day, but not by the 7th or subsequent days. On the other hand, using the ammonia end product, flux rate increased markedly (p < 0.0001) and remained elevated throughout the whole study. Our results demonstrate adaptive changes in whole body amino-nitrogen metabolism in response to the reducing diet. Different patterns of change are seen depending upon whether an ammonia or a urea end product is used. Our data thus add to the evidence for compartmentation of the body's amino-nitrogen pools.

1989 ◽  
Vol 256 (3) ◽  
pp. R583-R589 ◽  
Author(s):  
P. I. Mansell ◽  
I. A. Macdonald

Undernutrition leads to a reduction in sympathetic nervous system activity, but it is not established whether whole body responsiveness to catecholamines is also affected. The physiological responses to a 30-min infusion of epinephrine at 25 ng.kg-1.min-1 were studied in seven healthy, lean female subjects who had reduced their daily food intake to 60 kJ/kg ideal body weight for 7 days. Underfeeding led to greater epinephrine-induced increases in blood glycerol [peak increment 0.14 +/- 0.02 (SE) vs. 0.08 +/- 0.01 mmol/l, P less than 0.05] and beta-hydroxybutyrate concentrations (mean increment 0.30 +/- 0.05 vs. 0.13 +/- 0.04 mmol/l, P less than 0.05, analysis of variance). Compared with the normally fed state, in the underfed state epinephrine also caused greater increases in skin temperatures measured over the abdomen (0.94 +/- 0.08 vs. 0.67 +/- 0.06 degrees C, P less than 0.05) and over the thigh (1.00 +/- 0.07 vs. 0.61 +/- 0.12 degrees C, P less than 0.01). Underfeeding did not, however, affect the chronotropic, thermogenic, or other measured responses to epinephrine. Underfeeding therefore caused an enhancement of some but not all physiological responses to infused epinephrine.


1983 ◽  
Vol 61 (1) ◽  
pp. 72-80 ◽  
Author(s):  
H. G. Parsons ◽  
M. M. Wood ◽  
P. B. Pencharz

The pattern of urinary urea excretion and labelling with 15N was examined in eight meal-fed 6 to 9 year old children, over a 3-day period using a simulated constant infusion of the label. The children had cystic fibrosis but were healthy and in a good nutritional status at the time of the study. Reciprocal diurnal patterns of urea excretion and [15N]urea enrichment were noted and found to be suitable for mathematical description. Urea excretion was maximal in the evening at approximately 2000 and minimal at 0800, whereas the [15N]urea enrichment was maximal at about 0800 and minimal at 2000. In addition to the diurnal variation the [15N]urea enrichment increased exponentially to a plateau or isotopic steady state. The diurnal variation in [15N]urea enrichment resulted in large diurnal changes in the calculated rates of whole body amino nitrogen flux, synthesis, and breakdown. Flux rates were approximately 44% higher in the evening than in the morning. Synthesis rates were 19% higher in the evening, whereas breakdown rates were 27% greater in the morning. Mean amino nitrogen flux rates were 1.28 (SD 0.13) g N∙kg−1∙day−1. Isotope recycling was estimated from the slope of the [15N]urea enrichment curve between 30 and 54 h from the start of the study. There was a wide range in recycling, 2.9–19.4% (mean 11.4, SD 5.4). Some of the biological and pharmacological importance of the diurnal variation in the protein metabolism is discussed.


1983 ◽  
Vol 40 (10) ◽  
pp. 1622-1627 ◽  
Author(s):  
Alan W. Hopefl ◽  
Donald R. Miller ◽  
James D. Carlson ◽  
Beverly J. Lloyd ◽  
Brian Jack Day ◽  
...  

2021 ◽  
pp. 0310057X2096857
Author(s):  
Brian L Erstad ◽  
Jeffrey F Barletta

There is no consensus on which weight clinicians should use for weight-based dosing of neuromuscular blocking agents (NMBAs), as exemplified by differing or absent recommendations in clinical practice guidelines. The purpose of this paper is to review studies that evaluated various size descriptors for weight-based dosing of succinylcholine and non-depolarising NMBAs, and to provide recommendations for the descriptors of choice for the weight-based dosing of these agents in patients with obesity. All of the studies conducted to date involving depolarising and non-depolarising NMBAs in patients with obesity have assessed single doses or short-term infusions conducted in perioperative settings. Recognising that any final dosing regimen must take into account patient-specific considerations, the available evidence suggests that actual body weight is the size descriptor of choice for weight-based dosing of succinylcholine and that ideal body weight, or an adjusted (or lean) body weight, is the size descriptor of choice for weight-based dosing of non-depolarising NMBAs.


1991 ◽  
Vol 81 (5) ◽  
pp. 635-644 ◽  
Author(s):  
Alan A. Connacher ◽  
William M. Bennet ◽  
Roland T. Jung ◽  
Dennis M. Bier ◽  
Christopher C. T. Smith ◽  
...  

1. Energy expenditure, plasma glucose and palmitate kinetics and leg glycerol release were determined simultaneously both before and during adrenaline infusion in lean and obese human subjects. Seven lean subjects (mean 96.5% of ideal body weight) were studied in the post-absorptive state and also during mixed nutrient liquid feeding, eight obese subjects (mean 165% of ideal body weight) were studied in the post-absorptive state and six obese subjects (mean 174% of ideal body weight) were studied during feeding. 2. Resting energy expenditure was higher in the obese subjects, but the thermic response to adrenaline, both in absolute and percentage terms, was similar in lean and obese subjects. Plasma adrenaline concentrations attained (3 nmol/l) were comparable in all groups and the infusion had no differential effects on the plasma insulin concentration. Before adrenaline infusion the plasma glucose flux was higher in the obese than in the lean subjects in the fed state only (45.8 ± 3.8 versus 36.6 ± 1.0 mmol/h, P <0.05); it increased to the same extent in both groups with the adrenaline infusion. 3. Before the adrenaline infusion plasma palmitate flux was higher in the obese than in the lean subjects (by 51%, P <0.01, in the post-absorptive state and by 78%, P <0.05, in the fed state). However, there was no significant change during adrenaline infusion in the obese subjects (from 13.5 ± 1.00 to 15.0 ± 1.84 mmol/h, not significant, in the post-absorptive state and from 14.4 ± 2.13 to 15.7 ± 1.74 mmol/h, not significant, in the fed state), whereas there were increases in the lean subjects (from 8.93 ± 1.10 to 11.2 ± 1.19 mmol/h, P <0.05, in the post-absorptive state, and from 8.06 ± 1.19 to 9.86 ± 0.93 mmol/h, P <0.05, in the fed state). 4. Before adrenaline infusion the palmitate oxidation rate was also higher in the obese than in the lean subjects (1.86 ± 0.14 versus 1.22 ± .09 mmol/h, P <0.01, in the post-absorptive state and 1,73 ± 0.25 versus 1.12 ± 0.12 mmol/h, P <0.05, in the fed state). However, in response to adrenaline the fractional oxidation rate (% of flux) increased less in the obese than in the lean subjects, especially in the post-absorptive state (from 13.8 ± 1.02 to 14.9 ± 1.39%, not significant, versus from 13.7 ± 0.98 to 19.3 ± 1.92%, P <0.05). These effects were independent of feeding. Leg glycerol release increased more in the lean subjects with adrenaline infusion, although increases in the plasma glycerol concentration did not differ between the groups. 5. These results suggest that in obese subjects plasma inter-organ transport of fatty acids and the subsequent fractional oxidation responses favour storage of triacylglycerol. These factors may be important determinants for the development and maintenance of the obese state.


2001 ◽  
Vol 85 (2) ◽  
pp. 213-218 ◽  
Author(s):  
Shi-Yen Shiau ◽  
Jia-Fen Hsieh

An 8 week feeding trial was conducted to determine the dietary K requirement for juvenile hybrid tilapia (Oreochromis niloticus × O. aureus). Purified diets with eight levels (0, 1, 2, 3, 4, 5, 7, 10 g/kg diet) of supplemental K were fed to tilapia. Each diet was fed to three replicate groups of fish initially weighing a mean value of 0.77 (SE 0.01) g/fish in a closed, recirculating rearing system. Weight gain was higher (P<0.05) in fish fed the diets supplemented with 2, 3 and 4 g K/kg diet than in fish fed diet with 10 g K/kg diet and the unsupplemented control diet. Gill Na+-K+ ATPase activity was highest in fish fed the diets supplemented with 1–3 g K/kg diet, followed by fish fed the diet with 5 g K/kg diet and lowest in fish fed the diet with 10 g K/kg diet. Whole-body K content in fish were generally increased as the dietary K supplementation level increased. Analysis by polynomial regression of weight gain and gill Na+-K+ ATPase activity and by linear regression of whole-body K retention of the fish indicated that the adequate dietary K concentration for tilapia is about 2–3 g/kg diet.


2004 ◽  
Vol 91 (4) ◽  
pp. 585-590 ◽  
Author(s):  
Shi-Yen Shiau ◽  
Li-Shan Lu

Two 8-week feeding trials were conducted to determine the dietary Na requirement for juvenile hybrid tilapia (Oreochromis niloticus × O. aureus) reared in fresh water and seawater. In each experiment, NaCl was added to the basal diet at 0, 0·5, 1, 2, 3, 5, or 7g Na/kg diet (fresh water) and at 0, 0·2, 0·5, 0·8, 1·2, 1·5, 2, or 3g Na/kg diet (seawater). Each diet was fed to three replicate groups of fish, individual fish initially weighing 0·69 (se 0·01) g, in a closed, recirculating rearing system. In fresh water, the tilapia fed the diet supplemented with 2g Na/kg diet had significantly (P<0·05) greater weight gain than the fish fed the diets supplemented with ≥3 and ≤0·5g Na/kg diet. Feed efficiency (FE) in fish generally followed the weight-gain pattern. Gill Na+–K+ ATPase activity was highest in the fish fed the diets supplemented with 1–3g Na/kg diet, followed by the fish fed the diet with 7g Na/kg diet and lowest in the fish fed the unsupplemented control diet. In seawater, the weight gain, FE and gill Na+–K+ ATPase activity in fish were not affected by the dietary treatment. Analysis by polynomial regression of weight gain, by broken-line regression of gill Na+–K+ ATPase activity and by linear regression of whole-body Na retention of the fish reared in fresh water, indicated that the adequate dietary Na concentration for tilapia is about 1·5g/kg diet. The present study also suggests that no dietary Na is required for tilapia reared in seawater.


1984 ◽  
Vol 52 (3) ◽  
pp. 545-560 ◽  
Author(s):  
R. Giugliano ◽  
D. J. Millward

1. Male weanling rats were fed on diets either adequate (55 mg/kg), or severely deficient (0.4 mg/kg) in zinc, either ad lib. or in restricted amounts in four experiments. Measurements were made of growth rates and Zn contents of muscle and several individual tissues.2. Zn-deficient rats exhibited the expected symptoms of deficiency including growth retardation, cyclic changes in food intake and body-weight.3. Zn deficiency specifically reduced whole body and muscle growth rates as indicated by the fact that (a) growth rates were lower in ad lib.-fed Zn-deficient rats compared with rats pair-fed on the control diet in two experiments, (b) Zn supplementation increased body-weights of Zn-deficient rats given a restricted amount of diet at a level at which they maintained weight if unsupplemented, (c) Zn supplementation maintained body-weights of Zn-deficient rats fed a restricted amount of diet at a level at which they lost weight if unsupplemented (d) since the ratio, muscle mass:body-weight was lower in the Zn-deficient rats than in the pair-fed control groups, the reduction in muscle mass was greater than the reduction in body-weight.4. Zn concentrations were maintained in muscle, spleen and thymus, reduced in comparison to some but not all control groups in liver, kidney, testis and intestine, and markedly reduced in plasma and bone. In plasma, Zn concentrations varied inversely with the rate of change of body-weight during the cyclic changes in body-weight.5. Calculation of the total Zn in the tissues examined showed a marked increase in muscle Zn with a similar loss from bone, indicating that Zn can be redistributed from bone to allow the growth of other tissues.6. The magnitude of the increase in muscle Zn in the severely Zn-deficient rat, together with the magnitude of the total losses of muscle tissue during the catabolic phases of the cycling, indicate that in the Zn-deficient rat Zn may be highly conserved in catabolic states.


PEDIATRICS ◽  
1992 ◽  
Vol 89 (3) ◽  
pp. 522-522
Author(s):  
ALBERT C. HERGENROEDER

To the Editor.— This letter is in response to the article entitled "Weight and Menstrual Function in Patients with Eating Disorders and Cystic Fibrosis."1 Under "Methods," the authors describe a method for calculating percent ideal body weight by plotting the patient's height on standard growth curves derived from the data of Hamill et al,2 and the ideal body weight being the weight at the same percentile for age. Using the tables of Hamill to calculate percentages of height and weight for females older than 10 years and males older than 11½ years should be done cautiously.


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