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Results for “BASAL METABOLISM”

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At least 325 records · Page 18Linked to original sources
PubMed1990

Basal metabolic rate, nonshivering thermogenesis and cold tolerance in rat during undernutrition and subsequent nutritional rehabilitation.

Nutritional deprivation induced by increasing the litter size and subsequent dietary restriction results in rats having lower body weights and body lengths. Such undernourished rats have lower body temperatures as well as lower basal metabolic rate and nonshivering thermogenesis on a metabolic body weight basis; they also succumb on cold exposure to 5 degrees C. Nutritional rehabilitation by access to unlimited food reverses these changes to levels comparable to their control values.

Acclimatization↗
PubMed2005

Changes in basal metabolic rate during pregnancy in relation to changes in body weight and composition, cardiac output, insulin-like growth factor I, and thyroid hormones and in relation to fetal growth.

BACKGROUND: The total energy cost of pregnancy is largely due to an elevated basal metabolic rate (BMR). Large variations in the BMR response to pregnancy have been reported, but the factors associated with this variability are incompletely known. OBJECTIVE: The objective was to identify factors associated with variability in the BMR response to pregnancy. DESIGN: In 22 healthy women, BMR, body weight (BW), total body fat (TBF), fat-free mass (FFM), circulatory variables, serum concentrations of insulin-like growth factor I (IGF-I), and thyroid hormones were measured before pregnancy and in gestational weeks 14 and 32. BMR and BW were also measured in gestational weeks 8, 20, and 35. Fetal weight was estimated in gestational week 31. RESULTS: In gestational week 14, the increase in BMR correlated significantly with the corresponding increase in BW and with the prepregnancy percentage of TBF. Together these variables explained approximately 40% of the variability in the BMR response. In gestational week 32, the increase in BMR correlated significantly with the corresponding changes in BW, TBF, FFM, IGF-I, cardiac output, and free triiodothyronine. The increase in BW in combination with fetal weight or with the elevated concentration of IGF-I in serum explained approximately 60% of the variability in the increase in BMR. CONCLUSIONS: Weight gain and the prepregnancy percentage of TBF-ie, factors related to the maternal nutritional situation-are important factors with regard to the variability in the BMR response to pregnancy. Thus, it is important to consider the nutritional situation before and during gestation when assessing pregnancy energy requirements.

Adipose Tissue↗
PubMed1984

Role of thyroid and testicular hormones in the regulation of basal metabolic rate, gonad development, and body weight of spotted munia, Lonchura punctulata.

Normal saline, L-thyroxine (L-T4, 0.5 micrograms/bird/day), and testosterone (100 micrograms/bird/day) were administered separately to intact, thyroidectomized, and castrated spotted munia over a 30-day period and the effects on basal metabolic rate (BMR), gonads, and body weight were recorded. Thyroidectomy and castration decreased the BMR. L-Thyroxine increased the BMR of intact and thyroidectomized but not of the castrated birds. Testosterone had no effect on BMR of either the intact or of the operated birds. L-Thyroxine and testosterone both had no effect on regressing gonads but inhibited thyroidectomy-induced testicular development. Body weight increased in intact, testosterone-treated birds, and in thyroidectomized and castrated spotted munia. L-Thyroxine inhibited body weight gain only in thyroidectomized birds. It is suggested that the physiological actions of L-T4 and testosterone depend on the gonadal status, thyroid activity, and nature of the thyroid-gonad relationship.

Animals↗
PubMed2004

A comparison of self-reported energy intake with total energy expenditure estimated by accelerometer and basal metabolic rate in African-American women with type 2 diabetes.

OBJECTIVE: This study assesses the validity of dietary data from African-American women with type 2 diabetes by comparing reported energy intake (EI) with total energy expenditure (TEE) estimated by an accelerometer and basal metabolic rate (BMR). RESEARCH DESIGN AND METHODS: EI of 200 African-American women was assessed by three telephone-administered 24-h diet recalls using a multiple-pass approach. Physical activity was measured over a 7-day period by accelerometer, which also provided an estimate of TEE. Underreporting of EI was determined by using cutoffs for EI-to-TEE and EI-to-BMR ratios. RESULTS: Participants, on average, were 59 years of age, with a BMI of 35.7, 10.5 years of diagnosed diabetes, and 10.7 years of education. Mean EI was 1,299 kcal/day; mean EI-to-TEE and EI-to-BMR ratios were 0.65 and 0.88, respectively. Among the 185 subjects with complete dietary data, 81% (n=150) were classified as energy underreporters using the EI-to-TEE ratio cutoff; 58% (n=107) were classified as energy underreporters using the EI-to-BMR ratio. Energy underreporters had significantly lower reported fat, higher protein, but similar carbohydrate intakes compared with non-underreporters. The EI-to-TEE ratio was not significantly associated with any demographic variables or following a diet for diabetes, but it was inversely associated with BMI (r=-0.37, P<0.0001). In a multivariate model, demographic variables, BMI, and following a diet for diabetes explained 16% of the variance in the EI-to-TEE ratio, with the latter two variables being the only significant predictors (inversely associated). CONCLUSIONS: Widespread energy underreporting among this group of overweight African-American women with type 2 diabetes severely compromised the validity of self-reported dietary data.

Black or African American↗
PubMedDate not supplied

Basal metabolic rate in anorexia nervosa patients: using appropriate predictive equations during the refeeding process.

BACKGROUND: The refeeding process is a particularly dangerous time for some anorexia nervosa (AN) patients. Great physiologicatress can occur from imposing a large caloric intake on a body dealing with the effects of long-term starvation. Accurate predictive equations of basal metabolic rate (BMR) are needed to ensure AN patients gain weight at a safe rate. METHODS: Patients with AN undergoing strictly controlled nutritional rehabilitation on an inpatient unit were examined for changes in BMR via indirect calorimetry. Seven female patients were assessed shortly after inpatient admission. Follow-up measures of weight and BMR were obtained after three weeks of refeeding treatment comprised of approximately 3500 kcal/day. RESULTS: Body mass index (BMI) increased in all subjects from a median 13.7 kg/m2 at baseline to 15.2 kg/m2. BMR also increased from a median of 1000 kcal/day to 1220 kcal/day. The Owens and Mifflin equations were moderately accurate (within 10%) of predicted BMR at baseline and 3-week follow-up, and the Harris-Benedict equation was very accurate (within 2%) at 3-week follow-up only. CONCLUSIONS: These results may guide nutritional therapies for AN by demonstrating the suppression of metabolism induced by calorie restriction as well as its relatively prompt rebound to expected values with weight gain. Derivation of accurate predictive equations for use during the early refeeding period is needed.

Adult↗
PubMed1999

Membranes as possible pacemakers of metabolism.

Basal metabolic rate (BMR) varies dramatically among vertebrate species, both (i) being several fold higher in the endothermic mammals and birds compared to the ectothermic reptiles, amphibians and fish, and (ii) being much greater, on a body mass basis, in small vertebrates compared to large vertebrates. These differences in whole animal BMR are also manifest at the cellular level with substantial contributions to basal metabolic activity from the maintenance of various trans-membrane gradients. The percentage contribution of various processes to basal metabolism is remarkably consistent between different vertebrates and when BMR varies, the components of metabolic activity vary in relative unison. Membrane composition also varies between vertebrates and the degree of polyunsaturation of membrane phospholipids is correlated with cellular metabolic activity. In general, the tissue phospholipids and thus membrane bilayers of endotherms are more polyunsaturated than those from similar-sized ectotherms. In mammals membrane polyunsaturation is allometrically related to body mass. We suggest that membranes can act as pacemakers for overall metabolic activity. We propose that such membrane polyunsaturation increases the molecular activity of many membrane-bound proteins and consequently some specific membrane leak-pump cycles and cellular metabolic activity. We hypothesize a possible mechanistic basis for this effect that is based on a greater transfer of energy during intermolecular collisions of membrane proteins with the unsaturated two carbon units (C=C) of polyunsaturates compared to the single carbon units of saturated acyl chains, as well as the more even distribution of such units throughout the depth of the bilayer when membranes contain polyunsaturated acyl chains compared to monounsaturated ones. The proposed pacemaker role of differences in membrane bilayer composition is briefly discussed with respect to the brain (and sensory cells), evolution of mammalian endothermic metabolism, and its clinical implications for humans.

Animals↗