Displaying publications 21 - 40 of 72 in total

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  1. Naharudin MN, Yusof A
    PLoS One, 2013;8(10):e77290.
    PMID: 24204790 DOI: 10.1371/journal.pone.0077290
    BACKGROUND: Since hypohydration commonly occurs in sports, studies on anaerobic exercise performance under this condition have been extensively carried out. When describing anaerobic performance, authors usually refer to a drop in anaerobic performance as fatigue index (FI) which is conventionally calculated using peak and low power data points. Meanwhile, another possible method in explaining anaerobic fatigue is using the rate constant which is derived from the exponential decline of power output known as fatigue rate (FR). Few studies have demonstrated that there was no change in anaerobic performance under mild hypohydrations.

    PURPOSE: This study aimed to compare the kinetics of power output using FI and FR of an anaerobic performance (Wingate test) under 2, 3 and 4% state of hypohydrations.

    METHOD: Thirty two collegiate cyclists (age = 22 ± 2 years; body weight = 71.45 ± 3.43 kg; height = 173.23 ± 0.04 cm) were matched using their baseline anaerobic peak power (APP) then randomly divided into 4 groups of EU (euhydrated), 2H, 3H and 4H respectively.

    RESULTS: As expected the, FI, APP, anaerobic lower power (ALP) and rating of perceived exertion (RPE) did not show significant differences between and within the groups. However, the FR in 3H (0.018 ± 0.005 s(-1)) and 4H (0.019 ± 0.010 s(-1)) were significantly lower than EU (0.033 ± 0.012 s(-1)). Post-test FR also showed significant reduction in 3H and 4H compared to their pre-test values (p<0.05).

    CONCLUSION: Despite the lack of changes in APP and RPE, subjects in 3H and 4H showed evidence of lower reduction of power output over time. The findings support earlier reports which showed no change in anaerobic performance under mild hypohydrations. The relatively lower FR suggests higher drive in maintaining power output under hypohydrations of 3 and 4% body weight.

    Matched MeSH terms: Oxygen Consumption/physiology
  2. Shaharudin S, Ghosh AK, Ismail AA
    J Sports Med Phys Fitness, 2011 Dec;51(4):576-82.
    PMID: 22212259
    The present study was undertaken to evaluate the anaerobic capacity in repeated sprint cycling bouts during mid-luteal (ML) and mid-follicular (MF) phases of ovarian cycle.
    Matched MeSH terms: Oxygen Consumption*
  3. Jawis MN, Singh R, Singh HJ, Yassin MN
    Br J Sports Med, 2005 Nov;39(11):825-9; discussion 825-9.
    PMID: 16244191
    OBJECTIVES: Anthropometric and physiological profiles of national sepak takraw players were determined.
    METHODS: Thirty nine players, specialising in the three playing positions (tekong/server, feeder, and killer/spiker) were divided into three age categories of under 15 (U15), under 18 (U18), and under 23 (U23) years of age. Height, weight, percent body fat (%bf), maximum oxygen consumption (Vo(2max)), range of motion (ROM), back and leg strength, and heart rate, for the estimation of oxygen consumption during matches, were recorded. Statistical analysis was performed using one way ANOVA for independent measurements and data are presented as mean+/-standard deviation.
    RESULTS: The U23 players were significantly taller and heavier with significantly better ROM of the neck, trunk, and ankle joints and back and leg strength than the U15 players. No significant difference was found in %bf between the three age categories. Mean maximum heart rate during exercise was significantly higher in the U15 group when compared to the U18 and U23 groups (p<0.05). Mean Vo2max was similar between the three groups. Estimated oxygen consumption during matches was 69.1%, 68.5%, and 56.4% of Vo2max in the killer, tekong, and the feeder groups, respectively.
    CONCLUSIONS: The mean height, body weight, and cardiopulmonary capacities of the players were within the Malaysian population norms, but were somewhat lower than those of players of other court games from other countries. %bf was also lower in these players. This study provides the much needed anthropometric and physiological data of sepak takraw players for further development of this sport.
    Matched MeSH terms: Oxygen Consumption/physiology
  4. Kargarfard M, Lam ET, Shariat A, Asle Mohammadi M, Afrasiabi S, Shaw I, et al.
    Phys Sportsmed, 2016 09;44(3):208-16.
    PMID: 27291761 DOI: 10.1080/00913847.2016.1200442
    OBJECTIVES: Obesity prevalence has increased in Iranian adolescents in recent years. However, few studies have examined the impact of intervention programs on this health issue. The main objective of this study was to evaluate the effects of 8-week endurance training (ET) and high intensity interval training (HIIT) on intercellular adhesion molecule-1(ICAM-1) and vascular adhesion molecule-1(VCAM-1) levels among obese and normal-weight male adolescents.
    METHODS: Thirty obese and 30 normal-weight subjects were assigned to the ET, HIIT, or control group for eight weeks. Before and after the intervention, ICAM-1, VCAM-1, body weight, BMI, VO2max, and blood pressures were measured. SPSS (Version 21) was used for data analysis, and the significance level was set at p oxygen uptake
    Matched MeSH terms: Oxygen Consumption/physiology
  5. Ishak A, Hashim HA, Krasilshchikov O
    J Sports Med Phys Fitness, 2016 Sep;56(9):961-7.
    PMID: 26004044
    BACKGROUND: The present study investigated the effects of a 2-week modified exponential taper on physiological adaptation and time trial performance among junior cyclists.

    METHODS: Participants (N.=27) with the mean age of 16.95±0.8 years, height of 165.6±6.1 cm and weight of 54.19±8.1 kg were matched into either modified exponential taper (N.=7), normal exponential taper (N.=7), or control (N.=7) groups using their initial VO2max values. Both experimental groups followed a 12-week progressive endurance training program and subsequently, a 2-week tapering phase. A simulated 20-km time trial performance along with VO2max, power output, heart rate and rating of perceived exertion were measured at baseline, pre and post-taper. One way ANOVA was used to analyze the difference between groups before the start of the intervention while mixed factorial ANOVA was used to analyze the difference between groups across measurement sessions. When homogeneity assumption was violated, the Greenhouse-Geisser Value was used for the corrected values of the degrees of freedom for the within subject factor the analysis.

    RESULTS: Significant interactions between experimental groups and testing sessions were found in VO2max (F=6.67, df=4, P<0.05), power output (F=5.02, df=4, P<0.05), heart rate (F=10.87, df=2.51, P<0.05) rating of perceived exertion (F=13.04, df=4, P<0.05) and 20KM time trial (F=4.64, df=2.63, P<0.05). Post-hoc analysis revealed that both types of taper exhibited positive effects compared to the non-taper condition in the measured performance markers at post-taper while no different were found between the two taper groups.

    CONCLUSIONS: It was concluded that both taper protocols successfully inducing physiological adaptations among the junior cyclists by reducing the volume and maintaining the intensity of training.

    Matched MeSH terms: Oxygen Consumption/physiology*
  6. Rajikin MH
    Med J Malaysia, 1980 Sep;35(1):46-52.
    PMID: 6973059
    Seven non-anthletes [21-26 yrs] and five athletes [23-29 yrs] have participated in the study of cardiovascular and metabolic responses to 15 minutes isometric leg exercise at 15% of each of their maximal voluntary contraction force [MVC]. Oxygen consumption [V02 ]. heart rate [HR] and blood pressure (BP]. were measured during resting. exercise and recovery! periods. The results show that there were a significant increase in V02. HR and BP of the two groups studied during exercise, but no significant difference between groups has been found. This study indicates that although cardiovascular response between the rwo groups was not significantly different, 15 minutes isometric leg exercise at 15% MVC has challenged this system in a such a way to fulfill the metabolic requirement of the
    working muscle ill both groups. This finding was
    discussed in light of the available literatures.
    Matched MeSH terms: Oxygen Consumption*
  7. Okomoda VT, Mithun S, Chatterji A, Effendy MAW, Oladimeji AS, Abol-Munafi AB, et al.
    Fish Physiol Biochem, 2020 Aug;46(4):1497-1505.
    PMID: 32378001 DOI: 10.1007/s10695-020-00807-7
    This study was designed to optimize the culture conditions of juvenile Epinephelus fuscoguttatus (Forsskål, 1775) under laboratory conditions. To this effect, the rate of oxygen consumption was monitored as an index of stress under different temperature, salinity, pH, photoperiod, and urea concentrations. The result obtained after 12 h of exposure suggests the preference of the juvenile E. fuscoguttatus to a temperature range of 15-25 °C and salinity of 30 ppt. Based on this study, temperature was found to be the most lethal as 100% mortality was observed after 6 h in fish exposure to temperatures above the optimal (≥ 30 °C). However, the oxygen consumption rate was similar under the different pH, photoperiod, and urea concentration tested. It was concluded that water temperature was most critical in terms of respiration physiology of the juvenile E. fuscoguttatus given the range and levels of environmental factors tested in this study.
    Matched MeSH terms: Oxygen Consumption/physiology*
  8. Lim LS, Tan SY, Tuzan AD, Kawamura G, Mustafa S, Rahmah S, et al.
    Fish Physiol Biochem, 2020 Aug;46(4):1621-1629.
    PMID: 32430644 DOI: 10.1007/s10695-020-00817-5
    Oxyeleotris marmorata is an ambush predator. It is known for slow growth rate and high market demand. Farming of O. marmorata still remains a challenge. In order to establish a proper feeding practice to stimulate growth, knowledge of its metabolic processes and cost should be examined. Therefore, this study was designed to investigate the diel osmorespiration rhythms of O. marmorata in response to feeding challenge by using an osmorespirometry assay. The results have shown that oxygen consumption rate of the fed fish was approximately 3 times higher than that of the unfed fish in early evening to support specific dynamic action. Digestion and ingestion processes were likely to be completed within 18-20 h in parallel with the ammonia excretion noticeable in early morning. Under resting metabolism, metabolic oxygen consumption was influenced by diel phase, but no effect was noted in ammonia excretion. As a nocturnal species, O. marmorata exhibited standard aerobic metabolic mode under dark phase followed by light phase, with high oxygen consumption rate found in either fed or unfed fish. It can be confirmed that both the diel phase and feeding have a significant interactive impact on oxygen consumption rate, whereas ammonia metabolism is impacted by feeding state. High metabolic rate of O. marmorata supports the nocturnal foraging activity in this fish. This finding suggested that feeding of O. marmorata should be performed during nighttime and water renewal should be conducted during daytime.
    Matched MeSH terms: Oxygen Consumption/physiology
  9. Kidder GW, Montgomery CW
    Am J Physiol, 1975 Dec;229(6):1510-3.
    PMID: 2018
    We have recently shown that 5% CO2/95% O2 in the serosal bathing solution, with 100% O2 in the mucosal solution, results in CO2-diffusion limitation of acid secretion in bullfrog gastric mucosa. Changing to 10% CO2/90% 02 on both surfaces doubles the acid secretory rate. We calculate that, were the rate of oxygen consumption to increase significantly as a result of secretory stimulation, the tissue would now be oxygen limited. This prediction is tested by raising the P02 by increasing the total pressure in a hyperbaric chamber. Since no change in acid secretory rate or potential difference was observed upon changing from PO2 = 0.9 to PO2 = 1.9 atm, we conclude that the tissue is not O2 limited at normal pressure. Decreasing PO2 below 0.9 atm, by contrast, decreases the acid secretory rate and raises both PD and resistance. We infer that the rate of oxygen consumption did not rise significantly when acid secretion was increased by supplying sufficient CO2.
    Matched MeSH terms: Oxygen Consumption*
  10. Malik AA, Williams CA, Weston KL, Barker AR
    J Sports Sci Med, 2019 03;18(1):1-12.
    PMID: 30787646
    High-intensity interval exercise (HIIE) may not elicit prominent unpleasant feelings even with elevated perceived exertion and physiological stress in adolescents. However, the influence of different HIIE work intensities on the affective experience and cardiorespiratory responses is unknown. This study examined the acute affective, enjoyment, perceived exertion and cardiorespiratory responses to HIIE with different work intensities in adolescents. Participants (n = 16; 8 boys; age 12.0 ± 0.3 years) performed, on separate days, HIIE conditions consisting of 8 x 1-minute work-intervals at 70%, 85%, or 100% peak power separated by 75 seconds recovery at 20 W. Affect, enjoyment and rating of perceived exertion (RPE) were recorded before, during, and after HIIE. Heart rate (HR) and oxygen uptake were collected during HIIE. Affect declined in all conditions (p < 0.01) but 100%HIIE elicited significantly lower affect than 70%HIIE and 85%HIIE at work-interval 8 (all p < 0.02, ES > 1.74; 70%HIIE = 2.5 ± 0.8; 85%HIIE = 1.1 ± 1.5; 100%HIIE = -1.5 ± 1.4 on feeling scale). Similar enjoyment was evident during and after all conditions (all p > 0.44). RPE was significantly higher during 100%HIIE than 70%HIIE and 85%HIIE across all work-intervals (all p < 0.01, ES > 1.56). The majority of the participants attained ≥90%HRmax during 85%HIIE (87%) and 100%HIIE (100%), but not during 70%HIIE (6%). Affect responses during HIIE are dependent on the intensity of the work-interval and are not entirely negative (unpleasant feelings). Despite similar enjoyment, positive affect experienced during 70%HIIE and 85%HIIE could serve as a strategy to encourage exercise adoption and adherence in adolescents, but only 85%HIIE elicits sufficient HR stimulus to facilitate potential health benefits.
    Matched MeSH terms: Oxygen Consumption/physiology
  11. Ong TC
    J Sports Sci, 1993 Feb;11(1):71-6.
    PMID: 8450589 DOI: 10.1080/02640419308729966
    The maximum oxygen consumption (VO2 max) of 421 healthy adult males from three ethnic groups (Chinese, Malay and Indian), aged 25-54 years, was assessed from direct analyses of their expired respiratory gases during all-out runs on a treadmill as a measure of aerobic fitness. The subjects were divided into three age groups: group 1, 25-34 years; group 2, 35-44 years; group 3, 45-54 years. Each group was further subdivided into non-exercisers (NE), non-regular exercisers (NRE) and regular exercisers (RE). Consistently within each age group, regular exercisers produced significantly higher VO2 max values compared to non-regular exercisers and non-exercisers. They also met the VO2 max requirements for heavy physical work and compared favourably with the standards of the National Physical Fitness Award of Singapore and Cooper's aerobic fitness classification standards based on North American males. Non-regular exercisers and non-exercisers only met the VO2 max requirements for moderate physical work and compared poorly in both of the aerobic fitness standards.
    Matched MeSH terms: Oxygen Consumption*
  12. Shariat A, Cleland JA, Danaee M, Alizadeh R, Sangelaji B, Kargarfard M, et al.
    Work, 2018;60(4):549-554.
    PMID: 30103362 DOI: 10.3233/WOR-182762
    BACKGROUND: There are many potential training exercises for office workers in an attempt to prevent musculoskeletal disorders. However, to date a suitable tool to monitor the perceived exertion of those exercises does not exist.

    OBJECTIVE: The primary objective of this study was to examine the validity and reliability of the Borg CR-10 scale to monitor the perceived exertion of office exercise training.

    METHODS: The study involved 105 staff members employed in a government office with an age range from 25 to 50 years. The Borg CR-10 scale was self-administered two times, with an interval of two weeks in order to evaluate the accuracy of the original findings with a retest. Face validity and content validity were also examined.

    RESULTS: Reliability was found to be high for the Borg CR-10 scale (0.898). Additionally a high correlation between the Borg CR-10 scale and Visual Analog Scale (VAS) was identified (rs = 0.754, P 

    Matched MeSH terms: Oxygen Consumption/physiology
  13. Thent ZC, Das S, Henry LJ
    PLoS One, 2013;8(11):e80436.
    PMID: 24236181 DOI: 10.1371/journal.pone.0080436
    Background: Exercise training programs have emerged as a useful therapeutic regimen for the management of type 2 diabetes mellitus (T2DM). Majority of the Western studies highlighted the effective role of exercise in T2DM. Therefore, the main aim was to focus on the extent, type of exercise and its clinical significance in T2DM in order to educate the clinicians from developing countries, especially in Asians.

    Methods: Pubmed, Science Direct, Scopus, ISI Web of Knowledge and Google scholar were searched using the terms "type 2 diabetes mellitus," "type 2 DM," "exercise," and/or "physical activity," and "type 2 diabetes mellitus with exercise." Only clinical or human studies published in English language between 2000 and 2012 were included. Certain criteria were assigned to achieve appropriate results.

    Results: Twenty five studies met the selected criteria. The majority of the studies were randomized controlled trial study design (65%). Most of the aerobic exercise based studies showed a beneficial effect in T2DM. Resistance exercise also proved to have positive effect on T2DM patients. Minimal studies related to other types of exercises such as yoga classes, joba riding and endurance-type exercise were found. On the other hand, United States of America (USA) showed strong interest of exercise management towards T2DM.

    Conclusion: Aerobic exercise is more common in clinical practice compared to resistance exercise in managing T2DM. Treatment of T2DM with exercise training showed promising role in USA. A large number of researches are mandatory in the developing countries for incorporating exercise in the effective management of T2DM.
    Matched MeSH terms: Oxygen Consumption
  14. Eggleton P, Homathevi R, Jones DT, MacDonald JA, Jeeva D, Bignell DE, et al.
    Philos Trans R Soc Lond B Biol Sci, 1999 Nov 29;354(1391):1791-802.
    PMID: 11605622
    A synthesis is presented of sampling work conducted under a UK government-funded Darwin Initiative grant undertaken predominantly within the Danum Valley Conservation Area (DVCA), Sabah, East Malaysia. The project concerned the assemblage structure, gas physiology and landscape gas fluxes of termites in pristine and two ages of secondary, dipterocarp forest. The DVCA termite fauna is typical of the Sunda region, dominated by Termes-group soil-feeders and Nasutitermitinae. Selective logging appears to have relatively little effect on termite assemblages, although soil-feeding termites may be moderately affected by this level of disturbance. Species composition changes, but to a small extent when considered against the background level of compositional differences within the Sunda region. Physiologically the assemblage is very like others that have been studied, although there are some species that do not fit on the expected body size-metabolic rate curve. As elsewhere, soil-feeders and soil-wood interface-feeders tend to produce more methane. As with the termite assemblage characteristics, gross gas and energy fluxes do not differ significantly between logged and unlogged sites. Although gross methane fluxes are high, all the soils at DVCA were methane sinks, suggesting that methane oxidation by methanotrophic bacteria was a more important process than methane production by gut archaea. This implies that methane production by termites in South-East Asia is not contributing significantly to the observed increase in levels of methane production worldwide. Biomass density, species richness, clade complement and energy flow were much lower at DVCA than at a directly comparable site in southern Cameroon. This is probably due to the different biogeographical histories of the areas.
    Matched MeSH terms: Oxygen Consumption
  15. Singh R, Singh HJ, Sirisinghe RG
    Br J Sports Med, 1995 Mar;29(1):13-5.
    PMID: 7788209
    Maximal oxygen consumption (VO2max) and maximal workload attained (WLmax) were determined in 28 Malaysian dragon boat rowers who were exercised to exhaustion on an arm ergometer. Mean VO2max was 2.75 l min-1 at a mean WLmax of 195.5 W. Anaerobic endurance power of the arms, determined by cranking at 100 RPM at a workload of 400 W and the time taken to maintain the cadence until it fell to 75 RPM, was 34.9(+/- 2.3) s. Leg performance, as determined by standing long jump and vertical jump, was 140.0(+/- 4.5) kg m and 100.3(+/- 3.1) kg m s-1 respectively. Right hand grip strength was significantly (p < 0.001) greater than the left hand. Percentage body fat of the rowers was 11.8(+/- 0.6)%. These values represent the first measurements of their kind performed on dragon boat rowers in Malaysia.
    Matched MeSH terms: Oxygen Consumption
  16. Nagesh Chodankar N., Vinoth Kumar, Urban John Arnold D’Souza, Ahmad Faris Abdullah
    MyJurnal
    Introduction: Aerobic power reflects the physical fitness of the individual. Evidences support differences in phys-iological responses to exercise. There is less data on VO2 max among common ethnic population of Sabah. Ob-jective of this study was to investigate VO2 max among Kadazan, Dusun, Brunei Melayu, Bugis, Murut and others of Sabah in male and female young adult population. Methods: A total of 385 participants were randomly selected. Monark 894 E leg bicycle ergo meter was used to measure aerobic power VO2 max. Based on the heart rate male and female respectively 450 & 300 kilogram-force meter/minute was chosen. Based on Astrand rhyming nomogram (age correction factor included-VO2 Max multiplied by 1.05) calculations Vo2Max was calculated in l/min. The age correction done VO2 Max (l/min) was multiplied by 1000 and later divided by the body weight to derive the actual VO2Max in ml/kg/min. The recovery heart rate after 1 minute was taken and the difference were calculated for the further analysis. Data was tabulated and analysed by one way ANOVA test - Hocherberg’s GT2. Results: There was no significant difference in VO2 max between the common ethnic young adult population both in males and fe-males. Conclusion: There is no significant difference in VO2 max among the common ethnic adult but have a similar aerobic capacity in the study group.
    Matched MeSH terms: Oxygen Consumption
  17. Malays J Nutr, 2001;7(1):-.
    MyJurnal
    It is essential to replace fluids lost so as to remain well hydrated during exercise. The intake of fluids is considered a physiological ergogenic aid to enhance exercise performance. There are currently several products in the market that are believed to have ergogenic properties which act as fluid replacement drinks during exercise. One such drink available in the Malaysian market is ‘AgroMas®’ herbal drink whose efficacy is yet to be proven. The purpose of this study was, therefore, to evaluate the effects of acute ingestion of this herbal drink (H) or a coloured water placebo (P) on cycling performance. Nine healthy and trained young male cyclists (age: 16.2 ± 0.5 years) exercised on a cycle ergometer at 71.9 ± 0.7% of maximal oxygen consumption (VO2max) until exhaustion on two occasions at 1-week intervals. During each exercise bout, subjects received 3ml kg-1 body weight of H or P every 20 min in a double-blind randomised study design. There was no significant difference between H and P trials in the total work time to exhaustion (83.7 ± 4.6 and 81.5 ± 5.0 min respectively). Changes in oxygen consumption, heart rate and perceived rate of exertion were similar for both types of drinks. These results demonstrate that the herbal drink and the placebo elicited similar physiological responses and exercise performance during endurance cycling. It is therefore concluded that AgroMas® herbal drink and water ingestion resulted in a similar ergogenic response on cycling performance in young cyclists.
    Matched MeSH terms: Oxygen Consumption
  18. Elina RA, Husain R, Lang CC
    JUMMEC, 2005;8:9-22.
    Cardiopulmonary exercise testing is a non-invasive physiological test which incorporates the conventional method of exercise stress test with a more advanced breath-to-breath ventilatory analysis. The physiological parameters obtained from the test help to illustrate the cardiovascular, respiratory and metabolic responses to physical exertion. Individual's functional capacity and aerobic fitness is reflected by the value of maximal oxygen consumption (VO2 max) obtained from the cardiopulmonary exercise test. This non-invasive and sophisticated test is regarded as a valuable assessment tool in research and clinical practice. Cardiopulmonary exercise test has been extensively utilized to define the mechanisms of exercise intolerance in various clinical disorders, to evaluate responses to therapy and indicate disease prognosis. Emerging data obtained from the use of the cardiopulmonary exercise testing in the research field, has led to its extensive clinical usage. It is now utilized as an integral part of the patients' clinical evaluation in the field of respiratory and cardiovascular medicine, sports medicine, surgery as well as occupational and rehabilitative medicine. It has a clinical role in assessing patient's functional capacity, monitoring disease progression and response to therapy, predicting prognosis, and perioperative morbidity and mortality, as well as constructing and monitoring training and rehabilitative programs. This article aims to give an overview of the physiological profiles obtained from cardiopulmonary exercise testing, its methodological aspects, as well as its utility in research and clinical practice. KEYWORDS: Cardiopulmonary, exercise, physiology, respiratory medicine, oxygen consumption
    Matched MeSH terms: Oxygen Consumption
  19. Lee SM, Wong WP, Hiong KC, Loong AM, Chew SF, Ip YK
    J. Exp. Zoolog. Part A Comp. Exp. Biol., 2006 Dec 1;305(12):995-1009.
    PMID: 17068799
    This study aimed to determine effects of 6-day progressive increase in salinity from 1 per thousand to 15 per thousand on nitrogen metabolism and excretion in the soft-shelled turtle, Pelodiscus sinensis. For turtles exposed to 15 per thousand water on day 6, the plasma osmolality and concentrations of Na+, Cl- and urea increased significantly, which presumably decreased the osmotic loss of water. Simultaneously, there were significant increases in contents of urea, certain free amino acids (FAAs) and water-soluble proteins that were involved in cell volume regulation in various tissues. There was an apparent increase in proteolysis, releasing FAAs as osmolytes. In addition, there might be an increase in catabolism of certain amino acids, producing more ammonia. The excess ammonia was retained as indicated by a significant decrease in the rate of ammonia excretion on day 4 in 15 per thousand water, and a major portion of it was converted to urea. The rate of urea synthesis increased 1.4-fold during the 6-day period, although the capacity of the hepatic ornithine urea cycle remained unchanged. Urea was retained for osmoregulation because there was a significant decrease in urea excretion on day 4. Increased protein degradation and urea synthesis implies greater metabolic demands, and indeed turtles exposed to 15 per thousand water had significantly higher O2 consumption rate than the freshwater (FW) control. When turtles were returned from 15 per thousand water to FW on day 7, there were significant increases in ammonia (probably released through increased amino acid catabolism) and urea excretion, confirming that FAAs and urea were retained for osmoregulatory purposes in brackish water.
    Matched MeSH terms: Oxygen Consumption/physiology
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