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Biomedical subjects

J C Guilland

Publications and source records attributed to J C Guilland.

At least 19 recordsLinked to original sources
PubMed2005

Effect of a swim training on homocysteine and cysteine levels in rats.

The purpose of this study was to investigate the effects of a 8-week of swim training on total plasma homocysteine and cysteine levels in 16 male Sprague-Dawley rats aged 17 weeks. We also evaluated the activity of hepatic cystathionine beta-synthase (CBS), an enzyme involved in the metabolism of Hcy, the concentration of plasma glutathione, taurine, and a fraction of vitamin B6: the pyridoxal 5-phosphate (PLP). After one week of acclimatization, rats were randomly divided into two groups: 8 non-trained (NTR) and 8 trained rats (TR). Following the training period, body weight gain was lower in TR than in NTR. Plasma homocysteine did not differ among groups while significantly lower plasma cysteine and taurine levels were found in TR (157.83 +/- 8.6 micromol/L; 133.01 +/- 9.32 micromol/L; P < 0.05) compared with data of NTR (176.19 +/- 4.9 micromol/L; 162.57 +/- 8.16 micromol/L; P < 0.05). No significant changes in hepatic CBS activity were observed in TR compared with NTR. Moreover, values for plasma glutathione and PLP concentrations were not affected by training.These results indicate that training reduces plasma cysteine and taurine levels whereas it does not modify other studied parameters. Thus, physical training may regulate cysteine metabolism.

Animals↗
PubMed2003

Effects of a direct injection of liposoluble iron into rat striatum. Importance of the rate of iron delivery to cells.

For a better understanding of the role of iron imbalance in neuropathology, a liposoluble iron complex (ferric hydroxyquinoline, FHQ) was injected into striatum of rats. The effects of two modalities of iron injections on brain damage, hydroxyl radical (*OH) production (assessed by the salicylate method coupled to microdialysis) and tissue reactive iron level (evaluated ex vivo by the propensity of the injected structure for lipid peroxidation) were examined. Rapid injection of FHQ (10 nmoles of 5 mM FHQ pH 3 solution over 1-min period) but not that of corresponding vehicle led to extensive damage associated with increased tissue free iron level in the injected region. Conversely, neither lesion nor free iron accumulation was observed after slow FHQ injection (10 nmoles of a 100 microM FHQ pH 7 solution over 1-h period) as compared to corresponding vehicle injection. Production of *OH was induced by slow FHQ injection but not by rapid FHQ injection, probably as a result of in vivo abolition of iron-induced *OH formation by acid pH. Indeed, rapid injection of FAC pH 7 (ferric ammonium citrate, 5 mM in saline) was associated with *OH formation whereas rapid injection of FAC pH 3 did not. Our results identify the rate of iron delivery to cells as an important determinant of iron toxicity and do not support a major role for extracellular *OH in damage associated with intracerebral iron injection.

Animals↗
PubMed2001

Vitamin E-coated dialyzer reduces oxidative stress in hemodialysis patients.

The high incidence of cardiovascular disease in hemodialyzed (HD) patients is well established and oxidative stress has been involved in this phenomenon. The aim of our study was to evaluate if a vitamin E-coated dialyzer could offer protection to HD patients against oxidative stress. Sixteen HD patients were successively assessed for one month (i) on a high biocompatible synthetic dialyzer (AN) and (ii) on a vitamin E-coated dialyzer (VE). Blood samples were taken before and after the dialysis session at the end of each treatment period. HD session conducted with the AN dialyzer was responsible for acute oxidative stress, significantly assessed after HD by a decreased plasma vitamin C level and an increased ascorbyl free radical (AFR)/vitamin C ratio used as an index of oxidative stress. Plasma elastase activity, reflecting neutrophil activation, was also increased; soluble P-selectin, reflecting platelet activation, did not show any variation. The use of the VE dialyzer was associated with a less extended oxidative stress compared with the AN membrane: basal vitamin C level was higher, and after the HD session AFR/vitamin C ratio and elastase activity were not significantly increased. Plasma vitamin E levels were not affected. Our study demonstrates that HD is associated with oxidative stress, which can be partially prevented by the use of a vitamin E-coated dialyzer. Our data suggest that this dialyzer may exert a site-specific scavenging effect on free radical species in synergy with a reduced activation of neutrophils.

Aged↗
PubMed2001

Postischemic myocardial recovery and oxidative stress status of vitamin C deficient rat hearts.

OBJECTIVE: To investigate the role of vitamin C tissue content as a protective agent during myocardial ischemia-reperfusion injury, we have evaluated the postischemic functional recovery and free radical release of osteogenic disorder Shionogi (ODS) inherently scorbutic rat hearts and compared them to healthy Wistar rat hearts. METHODS: Isolated perfused hearts of ODS or Wistar rats underwent 30 min of a global total normothermic ischemia followed by 30 min of reperfusion. The lipid-soluble spin trap alpha-phenyl N-tert-butylnitrone (3 mM) was perfused upstream of the coronary bed. Functional parameters were recorded and samples of coronary effluents were analysed using electron spin resonance spectroscopy to characterise and quantify the amount of radical species released. RESULTS: From the onset of reperfusion, a large and long-lasting release of alkyl/alkoxyl radicals was detected, with a peak value of 29.0+/-3.2 nM obtained after 13 min, which was associated with a persistent contractile dysfunction. However, ODS rat hearts showed a higher myocardial recovery with lower left ventricular end diastolic pressure (44.34+/-1.74 vs. 55.03+/-1.57 mmHg for Wistar), higher recovery of rate pressure product (12.3+/-1.4 vs. 1.9+/-1.7x10(3) mmHg beats/min for Wistar) and shorter duration of contractile abnormalities during reperfusion (3.7+/-1.0 vs. 20.8+/-5.3 min for Wistar). Moreover, free radical release was identical in ODS rat hearts as compared to control Wistar rats. Ascorbic acid tissue content was significantly altered in ODS rats (31.9+/-3.3 vs. 591.0+/-54.9 mmol/g of tissue for Wistar) but superoxide dismutases, glutathion peroxidases and inducible heat shock protein 70 genes were up-regulated. CONCLUSIONS: This study shows that ascorbic-acid-deficient ODS rat hearts are more resistant to an ischemic insult than control Wistar rats, probably through the development of alternative protective defences, like the induction of heat shock proteins. These paradoxical results raise the question of the relative importance of each endogenous antioxidant in the cardiac resistance to ischemia-reperfusion injury.

Analysis of Variance↗
PubMed2001

Pre-clinical study of the epinephrine-cisplatin association for the treatment of intraperitoneal carcinomatosis.

We have previously shown that intraperitoneal (i.p.) epinephrine enhances tumour penetration and anti-cancer activity of i.p.-administered cisplatin in rats with peritoneal carcinomatosis. Here, we show a direct correlation between the i.p. epinephrine concentration and cisplatin accumulation in rat peritoneal tumour nodules up to a concentration of 5 mg/l. This concentration leads to a maximal 3.7-fold increase of tumour platinum content and a maximal vasoconstriction of the peritoneal and tumour superficial microcirculation when registered by a laser doppler probe. Further, epinephrine half-life was 20.8+/-3.6 min in the peritoneal cavity of two laparotomized pigs. In these animals, epinephrine plasma concentration, heart rate and systolic blood pressure were dependent on the intraperitoneal dose of epinephrine, and life-threatening signs were not observed in either animal. In conclusion, a 5 mg/l concentration of epinephrine could be safely maintained in peritoneal fluid by regular replacement. This concentration is sufficient to maintain a constant vasoconstriction of the peritoneal and tumoral microvascular bed, and enhance the slow diffusion of cisplatin into peritoneal tumour nodules in the course of per-operative intraperitoneal chemotherapy.

Animals↗
PubMed2000

Changes in thiamin, riboflavin, niacin, beta-carotene, vitamins, C, A, D and E status of French Elderly Subjects during the first year of institutionalization.

Vitamin status was assessed in 26 recently institutionalized elderly subjects by combining dietary and biochemical measurements of thiamin, riboflavin, niacin, beta-carotene, vitamins C, A, D and E at admission (P1), and 1.5 (P2), 3.0 (P3), 4.5 (P4), 6.0 (P5), 12 (P6) months later. At admission, except for vitamin A, mean vitamin intakes were lower than the 1992 French Recommended Dietary Allowance. Thiamin, vitamins C, A and E status seemed nearly satisfactory as less than one-fourth of the population sample had blood values lower than the cut-off point for thiamin (erythrocyte thiamin pyrophosphate < 0.17 mumol/l), vitamin A (serum retinol < 1.05 mumol/l), vitamin C (serum vitamin C < 11.3 mumol/l) and vitamin E (serum alpha-tocopherol < 9.3 mumol/l) or higher than the cut-off point for thiamin (erythrocyte transketolase activity coefficient > 1.19). Almost half of the subjects for riboflavin, and almost all non supplemented subjects for vitamin D were in risk of vitamin deficiency (46% had an erythrocyte glutathione reductase activity coefficient > 1.19 and 72% had a plasma 25(OH)D3 < 25 nmol/l). During the study, vitamins status remained unchanged for riboflavin, niacin, vitamins A, D and E, improved for vitamin C (P = 0.004) or impaired for thiamin (P = 0.008). Thus, institutionalization seemed to have no effect on riboflavin, niacin, vitamins A, D and E status and a slight effect on thiamin and vitamin C status.

Aged↗
PubMed2000

Folate status worsens in recently institutionalized elderly people without evidence of functional deterioration.

OBJECTIVE: To follow folate status, hematological and cognitive changes during the first year of institutionalization among elderly subjects. DESIGN: Prospective study. SETTING: Long-stay unit of the Dijon University Geriatric Hospital. SUBJECTS: Twenty women and four men older than 65 years admitted consecutively. MAIN OUTCOME MEASURES: Folate and vitamin B-6 dietary intake was evaluated by a five-day record on admission (day 1 or d 1), at day 45 (d 45), day 90 (d 90), day 135 (d 135), day 180 (d 180), day 360 (d 360). Circulating levels of folate, vitamin B-6, total homocysteine (tHcy), blood counts and cognitive performance were determined in parallel. RESULTS: From d 1 to d 360, mean folate and vitamin B-6 intakes remained below the French RDA and mean folate intakes decreased significantly (delta = 10.2%, p < 0.05). Mean plasma or erythrocyte folate decreased significantly (delta = 33.7%, p <0.05 and delta = -30.2%, p < 0.001, respectively) from d 1 to d 360; no significant change was observed for the other blood parameters. The incidence of folate deficiency increased (8% vs. 37% for plasma folate <6.8 nmol/L and 8% vs. 17% for erythrocyte folate <340 nmol/L) from d I to d 360. Mean plasma pyridoxal 5'-phosphate (PLP) remained <20 nmol/L during the one-year follow-up. There was no difference between genders for plasma tHcy. Although mean plasma tHcy was <14 micromol/L. plasma tHcy was >14 micromol/L in about one-third of the subjects. At each period, 50% or more subjects were anemic (Hct <35% in women and Hct <40% in men), but the anemia was normocytic (MCV <100 fL). Subjects had a moderate dementia at admission, and no change was observed during the study. CONCLUSIONS: Subjects were already vitamin B-6 deficient at admission. Folate status was impaired during the study. Low vitamin intakes were the main cause of vitamin B-6 deficiency and folate status deterioration. Hematology and mental status capacity were not aggravated by folate status deterioration. Plasma tHcy didn't appear to be an earlier predictor of folate deficiency.

Aged↗
PubMed2000

5,10-methylenetetrahydrofolate reductase common mutations, folate status and plasma homocysteine in healthy French adults of the Supplementation en Vitamines et Mineraux Antioxydants (SU.VI.MAX) cohort.

The 677cytosine mutation identified in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene has been frequently associated with an elevated plasma homocysteine concentration. The aim of the present study was to determine the impact of this MTHFR common mutation on plasma and erythrocyte folate (RCF) and plasma total homocysteine (tHcy) concentrations in healthy French adults. A cohort of 291 subjects living in the Paris area and participating in the Supplementation en Vitamines et Mineraux Antioxydants (SU.VI.MAX) study were analysed to assess the impact of MTHFR polymorphism 677C-->T on folate status and plasma tHcy concentration. The frequency of the mutant homozygote for 677C-->T polymorphism (677TT genotype) in the present cohort was 16.8%. There were significant differences in plasma tHcy between 677CC, 677CT and 677TT genotype groups. The RCF concentrations were significantly different between each genotype, the lowest levels being associated with the 677TT genotype. When segregated by gender, no differences in tHcy between homozygous 677TT, heterozygous 677CT and wild-type 677CC genotype groups in women were observed. The fasting tHcy in women was unrelated to the 677C-->T mutation. However, tHcy was significantly increased in men with the homozygous 677TT genotype. We also analysed the possible implication of a second new MTHFR polymorphism (1298A-->C) in subjects with mild hyperhomocysteinaemia (4th quartile of homocysteinaemia; tHcy >11.1 micromol/l). The polymorphism 1298A-->C did not have a notable effect on tHcy or on the RCF levels. Our observations confirm a relatively high frequency of the 677TT genotype in the French population. Women with this genotype did not show the same increase in tHcy observed in men. In the present study dietary folate intake was not measured. Thus, the interaction of dietary folate with the MTHFR genotype in the French population needs further study.

5,10-Methylenetetrahydrofolate Reductase (FADH2)↗
PubMed1997

Chronic exercise affects vitamin B-6 metabolism but not requirement of growing rats.

The effect of chronic exercise (forced swimming) on vitamin B-6 status and metabolism was studied in growing male rats fed deficient (0 mg pyridoxine-HCl/kg), suboptimal (2 mg pyridoxine-HCl/kg) or control (7 mg pyridoxine-HCl/kg) diets for 9 wk. Sedentary rats were fed the same diets. Body weight gain was lower in deficient rats than in both other dietary groups. Sedentary rats were heavier than trained rats of all diet groups. Erythrocyte aspartate aminotransferase, urinary 4-pyridoxic acid excretion, blood (plasma and erythrocytes) and tissue B-6 vitamers were measured. Urinary 4-pyridoxic acid, plasma pyridoxal 5'-phosphate and erythrocyte aspartate aminotransferase values of exercised and sedentary rats responded to changes in dietary pyridoxine but were not different from one another. After 9 wk of vitamin B-6 depletion, tissue concentrations of pyridoxal 5'-phosphate and pyridoxamine 5;5'-phosphate were 41-66% and 26-49% lower, respectively, in the deficient groups than in the control groups. Larger percentage differences occurred in plasma than in tissues (95 vs. 22-66%). In liver, pyridoxal 5'-phosphate concentrations were lower, whereas pyridoxal concentrations were higher in trained than in sedentary rats. In gastrocnemius muscle, pyridoxal 5'-phosphate, pyridoxamine 5'-phosphate and total vitamin B-6 concentrations were higher in trained than in sedentary rats. Concentrations of vitamin B-6 compounds in heart, kidneys, brain and adrenals were not affected by training. On the basis of the vitamin B-6-dependent variables measured in this study, we conclude that prolonged exercise affects the metabolism of vitamin B-6, but does not increase the vitamin B-6 requirement in growing rats.

Animals↗
PubMed1997

Vitamin B6 and vitamin C status in elderly patients with infections during hospitalization.

We have evaluated whether vitamin B6 and C metabolism may be altered by infection in the elderly. Vitamin B6 and C biochemical status has been assessed for times over a period of 21 days (days 0, 7, 14, and 21) in 18 subjects > or = 75 years. The subjects were divided into 3 groups: group I (8 subjects with acute infection), group II (4 malnourished subjects), and group III (6 control subjects). Vitamin B6 status was determined by plasma pyridoxal-5'-phosphate (PLP) and erythrocyte aspartate aminotransferase activation coefficient (alpha-EAST), and vitamin C status by plasma ascorbic acid. During the 3 weeks, vitamins B6 and C values were significantly different between groups: at days 7 and 14, PLP values were significantly higher in group III than in both groups I and II, and alpha-EAST values were significantly higher in group I than in both groups II and III. Plasma ascorbate values were significantly lower in group I than in both groups II and III. These data suggest that an acute catabolic state like infection may influence vitamin B6 and C metabolism. Nevertheless, more work is needed to assert that vitamin B6 and C supplementation may be useful during infection.

Acute-Phase Proteins↗
PubMed1996

Effects of exhaustive exercise and vitamin B6 deficiency on free radical oxidative process in male trained rats.

There is growing evidence that oxygen free radical production and subsequent lipid peroxidation are normal sequelae to the rise in oxygen consumption concomitant with exercise. In addition, increased lipid peroxidation has also been shown in vitamin B6-deficient rat plasma, liver, and kidney. To investigate the potential for a role of vitamin B6 in exercise-induced oxidative stress, 36 male Sprague-Dawley rats received 0 (n = 12), 2 (n = 12), and 8 mg pyridoxine (PN)-HCl/kg diet (n = 12) and were trained by a 9-week swimming program. After 9-weeks of training, six rats (exhausted: E rats) of each vitamin group were exercised to exhaustion by swimming while the other six rats rested (nonexhausted: NE rats). Ascorbate, ascorbate free radical and antilipoperoxidant capability (AC) were evaluated in plasma. These parameters were higher in E rats than in NE rats. Free radical-mediated lipid peroxidation was measured in tissue and plasma by evaluation of thiobarbituric acid reactive substances (TBARS) content. This index of peroxidation was significantly increased in liver of E rats but not in plasma, heart, and gastrocnemius muscle. Concentration of TBARS in liver was the highest in vitamin B6-deficient rats (consuming 0 mg PN-HCl/kg diet) and the lowest in vitamin B6-sufficient rats (consuming 8 mg PN-HCl/kg diet). Vitamin E (alpha-tocopherol) levels in liver and heart were negatively related to vitamin B6 levels in the diet. Independently of vitamin B6, liver and muscle alpha-tocopherol levels were significantly higher in E animals than in NE animals. There is good evidence according to our results that exercise induced an oxidative stress, as indicated by a significant increase of ascorbyl radical levels in the plasma. The effects of vitamin B6 deficiency on the free radical metabolism are low in trained rats. On the contrary, exhaustive exercise induced modifications in the metabolism pathways of vitamin C and E objectivated by variations of levels of vitamin C in the plasma and vitamin E in liver.

Animals↗
PubMed1996

Vitamin status of healthy subjects in Burgundy (France).

A nutrition survey was conducted in Burgundy (France) with a population sample of 337 middle-aged and healthy subjects (157 males and 180 females) recruited at a health examination center in 1985-1986. The status of beta-carotene, thiamin, riboflavin, folate, vitamin B6, B12, C, A, D, and E was assessed by means of 7-day food records and biochemical studies. Results were compared with two other recent nutritional surveys conducted in France: ESVITAF (control group only) and Val de Marne surveys. The dietary information collected for each subject was compared to the 1992 French Recommended Dietary Allowances (FRDA). Dietary vitamin intakes were higher in males than in females. Low vitamin intakes (< 1/2 FRDA) were found in 5% of males and 7% of females for thiamin, in 11% of males and 28% of females for vitamin B6, in 6% of males and 3% of females for vitamin C, in 87% of males and 91% of females for vitamin D, and in 8% of males and 13% of females for vitamin E. No subject had a vitamin intake < 1/2 FRDA for riboflavin, folate, vitamins A and B12. ESVITAF and Val de Marne studies also show low vitamin intakes for vitamin B6, thiamin, riboflavin, vitamins D and E. Biochemical status was examined using erythrocyte enzyme function and blood vitamin levels. The percent of subjects with deficient biochemical values was high for vitamin B6 (15% of all males and 20% of all females), and vitamin D (13% of all males, and 15% of all females). With regard to thiamin, riboflavin, vitamin C, folate, vitamin B12, vitamin A, and vitamin E, < 5% of subjects had values in the range of major vitamin deficiency. However, in both genders, except for vitamin C and vitamin A (only for females), low values corresponding to a moderate risk of vitamin deficiency was high for most vitamins. The incidence of a severe deficient vitamin status for thiamin and riboflavin was higher in Val de Marne than in Burgundy, or ESVITAF. In Val de Marne, the probability of a moderate risk of vitamin deficiency was high for thiamin, riboflavin, vitamin B6, vitamin A and vitamin E. Our results (as other studies performed in France and in other industrialized countries) raise the issue of the health significance of marginally deficient vitamin status.

Adolescent↗
PubMed1996

Validation of a micromethod for determining oxidized and reduced vitamin C in plasma by HPLC-fluorescence.

An HPLC micro-method with fluorescence detection has been developed to determine total vitamin C (vit C) and dehydroascorbic acid (DHA) concentrations in human plasma samples. This method is based on the rapid, specific reaction of DHA with dimethyl-o-phenylenediamine (DMPD) to form a fluorescent quinoxaline derivative that is quantified by HPLC in less than 5 minutes. The method was assessed with reference to the direct 2,4-dinitrophenylhydrazine (DNPH) colorimetric method. They were well correlated (r3 = 0.879), but the DMPD-HPLC method had the limit of detection 6 times lower than the standard method and the relative error for a vitamin standard was 10 times better than that of the standard method. The plasma DHA to total vit C ratio varied from 10 to 60%, depending on sample processing. Plasma that were immediately analysed contained 10% DHA whatever the subject's age; frozen deproteinized samples kept 1 week (-67 degrees C) had 20%, and blood samples kept for one hour at room temperature before treatment had up to 60% DHA. The ratio in capillary samples taken from the finger was 11-42%. This rapid, specific and very sensitive micro-method is well suited to routine measurements of plasma vit C.

Adult↗
PubMed1995

Effects of electromyostimulation and strength training on muscle soreness, muscle damage and sympathetic activation.

Electromyostimulation (EMS) is known to develop muscular strength and hypertrophy. The aim of this study was to compare EMS exercise-induced damage with concentric (CONC) exercise-induced damage. Twelve male athletes were randomly assigned to concentric exercise (five sets of 6 voluntary contractions) or to EMS (30 contractions of 6 s duration, 20 s rest between contractions) on day 0 (D0). The load was 80% of the maximal isometric force. Criterion measures of plasma creatine kinase (CK) activity and lactate dehydrogenase (LDH) activity, and subjective ratings of muscle soreness and urinary catecholamines, were assessed 1 day before and for 3 days after exercise. Among the members of the EMS group, there were significant increases in catecholamine urinary excretion, especially adrenaline (on days D+2 and D+3), plasma CK activity (on day D+2) and plasma LDH activity (on days D+1 and D+2). The changes among the members of the CONC group were smaller and no significant difference was noted. Muscular soreness was greatest in the EMS group, with the peak occurring on day D+2. Comparisons of enzyme release, muscular soreness and urinary catecholamines suggest that EMS induces myofibre membrane damage and a significant increase in sympathetic nervous activity.

Adult↗
PubMed1994

Thiamine status of elderly patients with cardiac failure including the effects of supplementation.

This study compared the thiamine status of 35 elderly hospital inpatients with cardiac failure (CF) with that of 35 elderly inpatients with other diagnoses (Non-CF). The CF group was then randomly allocated to CF1 group (thiamine treatment, 200 mg per day for 7 days), and CF2 group (non supplemented). The effect of the thiamine treatment on the cardiac failure course was examined. Although there was no significant difference in thiamine status between CF and Non-CF groups, 11.5% of the first group against only 6.0% of the second was deficient with the thiamine pyrophosphate stimulation effect (TPPE) test. The same trend was observed, if NYHA functional assessment was taken into account, thiamine deficiency was more frequent in class 4 than in class 3. No significant difference for thiamin status was observed in patients receiving furosemide treatment and those without furosemide treatment. Although vitamin treatment permitted a significant improvement in thiamine status, the course of the cardiopathy was not significantly different in CF1 (supplemented) and CF2 (non supplemented) groups. Whether systematic thiamine supplementation is indicated in CF patients requires further investigation.

Aged↗
PubMed1993

Computerized analysis of food records: role of coding and food composition database.

Reported dietary intake records of 30 subjects (26 men and 4 women) were analysed by three different centres using their own computerized nutrient database systems. The agreement between systems was evaluated by different statistical criteria (the correlation coefficient, the mean difference and the proportion of individuals placed in the same thirds of distribution). Significant differences between the three systems were found in the calculation of alcohol, polyunsaturated fatty acids, saturated fatty acids, linoleic acid, linolenic acid, cholesterol, magnesium, sodium and water. To ascertain the extent of mean differences that could be attributed to the coding process or to the database used, coding forms of each centre were forwarded to the other two centres. Analysis of variance showed that differences in the data obtained by the three systems were mainly due to the food composition database used.

Analysis of Variance↗
PubMed1993

Effect of chronic potassium depletion on muscle bioenergetics in rats.

To test the hypothesis of muscle bioenergetic impairment in potassium depletion, chronic potassium-depleted rats and pair-fed control rats were studied with phosphorus 31 nuclear magnetic resonance measurements of leg muscle intracellular pH, phosphocreatine, inorganic phosphate, and adenosine triphosphate at rest and during maximal nontetanic stimulation, 48 hours after a swimming test. The potassium-depleted rats exhibited a significant hypokalemia, a metabolic extracellular alkalosis, and an intracellular acidosis. Their physical endurance was markedly reduced, and they displayed higher plasma creatine kinase levels than the control group. However, the phosphocreatine/inorganic phosphate ratio, which is a measure of the energy reserve of the cell, was similar in both groups at rest and during electrical stimulation and subsequent recovery. Resting muscle glycogen and relative intracellular acidification during stimulation did not differ in the two groups, arguing against an impairment of anaerobic metabolism in potassium depletion. These results indicate that the energy availability of muscle cell is unchanged during potassium deficiency.

Animals↗