Carnosine Levels Research Articles

High Level of Skeletal Muscle Carnosine Contributes to the Latter Half of Exercise Performance during 30-s Maximal Cycle Ergometer Sprinting.

The histidine-containing dipeptide carnosine (beta-alanyl-L-histidine) has been shown to significantly contribute to the physicochemical buffering in skeletal muscles, which maintains acid-base balance when a large quantity of H(+) is produced in association with lactic acid accumulation during high-intensity exercise. The purpose of the present study was to examine the relations among the skeletal muscle carnosine concentration, fiber-type distribution, and high-intensity exercise performance. The subjects were 11 healthy men. Muscle biopsy samples were taken from the vastus lateralis at rest. The carnosine concentration was determined by the use of an amino acid autoanalyzer. The fiber-type distribution was determined by the staining intensity of myosin adenosinetriphosphatase. The high-intensity exercise performance was assessed by the use of 30-s maximal cycle ergometer sprinting. A significant correlation was demonstrated between the carnosine concentration and the type IIX fiber composition (r=0.646, p<0.05). The carnosine concentration was significantly correlated with the mean power per body mass (r=0.785, p<0.01) during the 30-s sprinting. When dividing the sprinting into 6 phases (0-5, 6-10, 11-15, 16-20, 21-25, 26-30 s), significant correlations were observed between the carnosine concentration and the mean power per body mass of the final 2 phases (21-25 s: r=0.694, p<0.05; 26-30 s: r=0.660, p<0.05). These results indicated that the carnosine concentration could be an important factor in determining the high-intensity exercise performance.

SKELETAL MUSCLE CARNOSINE LEVEL MAY CONTRIBUTE TO SUPERIOR PERFORMANCE DURING HIGH INTENSITY EXERCISE

Dipeptide carnosine (β-alanyl-L-histidine) has been shown to contribute significantly to physico-chemical buffering in skeletal muscle, which maintains acid-base balance when large quantities of hydrogen ions are produced in association with lactic acid accumulation during high intensity exercise. The purpose of this study was to examine relationships among skeletal muscle carnosine level, fiber type distribution and high intensity exercise performance. The subjects were twenty healthy men. Muscle biopsy samples were taken from the vastus lateralis at rest. Carnosine level were determined using an amino acid AutoAnalyzer. Fiber type distribution was determined by staining intensity of myosin adenosinetriphosphatase. High intensity exercise performance was assessed using 30-s cycle ergometer sprinting. Significant (P < 0.05) interrelationships were demonstrated between carnosine level and type II fiber composition. Superior sprint performance was associated with type II fiber composition and carnosine level. When dividing the 30-s sprinting into 6 phases (0–5, 6–10, 11–15, 16–20, 21–25, 26–30 s), significant correlations were observed between carnosine level and mean power of the latter 3 phases (16–20 s: P < 0.05, 21–25 s: P < 0.01 and 26–30 s: P < 0.05). These results indicate that carnosine level may be an important determinant of high intensity exercise performance.

High Levels of Dietary Carnosine Are Associated with Increased Concentrations of Carnosine and Histidine in Rat Soleus Muscle

The aims of this investigation were to: 1) determine the effect of a moderately high dose of carnosine on muscle concentrations of carnosine, histidine and vitamin E at deficient, minimally adequate and sufficient levels of dietary vitamin E and 2) compare the effects of moderately high and pharmacological doses of carnosine on muscle concentrations of carnosine, histidine and vitamin E when dietary vitamin E is minimally adequate. Muscle concentrations of carnosine, histidine and vitamin E were measured in the lateral gastrocnemius and red and white vastus lateralis; carnosine and histidine concentrations were also measured in soleus muscle. Male Sprague-Dawley rats (n = 12/group) were fed a basal vitamin E-deficient diet supplemented with either 0, 0.001 or 0.01% vitamin E and 0, 0.1 or 1.8% carnosine. After 8 wk, 1.8% carnosine resulted in significant fivefold increases in carnosine and twofold increases in histidine in the soleus muscle (P < or = 0.05). Muscle vitamin E concentrations were not significantly affected by dietary carnosine. Thus, very high levels of dietary carnosine are associated with increases in carnosine and histidine concentrations in rat soleus muscle.

Low taurine, gamma-aminobutyric acid and carnosine levels in plasma of diabetic pregnant rats: consequences for the offspring.

Gestational diabetes compromises fetal development and induces a diabetogenic effect in the offspring, including the development of gestational diabetes and the transmission of the effect to the next generation. Changes are not limited to glucose and insulin metabolism, and appear to be modulated by alterations at the hypothalamo-hypophyseal axis. In the present work, serum concentrations are given for the non-protein amino-acids taurine and gamma-aminobutyric acid (GABA), both neurotransmitters essential for normal brain development, and for the endogenous neuroprotector carnosine, a known anti-oxydans. Taurine levels are significantly below normal values in mildly diabetic mothers, in their fetal and adult offspring, virgin and pregnant, and in the fetuses of these pregnant offspring. GABA and carnosine levels are at the limit of detection in the diabetic mothers and their offspring at every stage. It is concluded that the low taurine, GABA and carnosine levels in diabetic mothers and their fetuses might compromise the normal structural and functional development of the fetal brain. When adult, these offspring present a deficiency of the circulating levels of these neurotransmitters involved in the hypothalamo-hypophyseal regulation of insulin secretion. This might contribute to the development of impaired glucose tolerance and gestational diabetes, thereby transmitting the effect to the next generation.

HPLC Determination of Carnosine in Commercial Canned Soups and Natural Meat Extracts

The skeletal muscle of vertebrates is a rich source of carnosine (β -alanyl- L -histidine). Fourteen commercially available canned soup products were screened for carnosine content by a simple and sensitive ion-exchange HPLC method. Carnosine in the soup fluid ranged from 0 to 0.35 mg/g sample. Though water soluble, carnosine was not detected in four of the nine samples of soup fluid which carried the tag ‘beef’ in their labels. Among the commercially available natural meat extracts with Brix values varying from 52 to 78, beef meat extract with Brix 78 was comparatively rich in carnosine (37.5–38.2 mg/g sample) compared to bonito extract with Brix 67–80, in which carnosine levels varied from 5.0 to 7.9 mg/g sample.

Concentrations of free carnosine (a putative membrane-protective antioxidant) in human muscle biopsies and rat muscles

Carnosine has possible functional effects on skeletal muscle contractility, along with membrane-protective, antioxidant effects. We determined tissue free carnosine concentrations in skeletal muscles from patients with neuromuscular diseases and in skeletal and heart muscles from rats of various ages. The effects of age, gender and diagnostic category on free carnosine levels in patients with neuromuscular diseases were analyzed by a stepwise multiple linear regression model. The age of the patients emerged as a significant negative predictor of carnosine concentrations ( R=−0.40, P<0.05). Free carnosine concentrations in rat skeletal muscles also showed a significant negative correlation with the ages of the rats (male rats: R=−0.49, P<0.05; female rats: R=−0.56, P<0.05). Only the diagnostic category amyotrophic lateral sclerosis (ALS) emerged as a significant negative predictor compared to the control group in the stepwise regression model, this was confirmed by Wilcoxon Signed Rank Test ( P<0.05). We conclude that the age-related decline in muscle mass, strength and function is associated with decreased tissue concentrations of the putative membrane-protective antioxidant carnosine. In addition we found decreased carnosine tissue concentrations in ALS. The reduction in carnosine content might be caused by progressive denervation processes.

Inhibition of Lipid Oxidation in Chicken by Carnosine and Dietary α-Tocopherol Supplementation and its Determination by Derivative Spectrophotometry

The antioxidant activity of carnosine in chicken meat, and its relationship to dietary α-tocopherol supplementation, was examined. Broiler chickens were fed diets containing 30 (basal) or 200 (supplemental) mg α-tocopherol acetate kg −1 feed for 6 weeks. Raw and cooked thigh meat patties containing carnosine (0–1·5%) were prepared. Lipid oxidation, during refrigerated storage under fluorescent light, was assessed by monitoring malonaldehyde formation, using the TBA assay and single wavelength (conventional) or first derivative spectrophotometry. In raw patties, added carnosine improved oxidative stability for up to 10 days of refrigerated storage. In cooked patties, the 1·5% carnosine level provided the best antioxidant protection during 7 days of storage. Carnosine (1·5%) was at least as effective as supplemental α-tocopherol in improving the oxidative stability of raw and cooked patties. The presence of both antioxidants had an additive effect on oxidative stability. Overall, the use of derivative spectrophotometry improved the specificity of the TBA assay for monitoring MDA formation in refrigerated meats.

Behavioral, histological, and neurochemical effects of nickel (II) on the rat olfactory system.

Experimentally, inorganic, sulfated nickel compounds (Ni2+) have been shown to produce histological lesions in the nasal mucosa of rats, more specifically, atrophy of the olfactory epithelium. The present project was designed to assess the effects of inhalation of nickel sulfate hexahydrate on behavioral, histological, and neurochemical aspects of the olfactory system. Male Long-Evans rats were exposed to either background air (control) or 635 micrograms Ni/m3 for 16 consecutive days, 6 hr/day. Exposure resulted in selective lesions to the olfactory epithelium. The number of bipolar sensory receptor cells was slightly reduced and there was a significant decrease in the thickness of the olfactory epithelium. This was due primarily to a significant loss of the sustentacular cell population, with a thinning of the apical cytoplasm, concomitant with a reduction in the number of microvilli at the surface of these cells. Significant decreases in carnosine level, consistent with the nickel sulfate exposure, were observed. However, there were no changes in olfactory function as measured by either absolute threshold or two-oder discrimination tasks.

Effects of calpain on antioxidant enzyme activities.

The activities of superoxide dismutase, catalase and glutathione reductase were not affected by in vitro incubation with the intracellular proteinase calpain, suggesting that these enzymes are not in vivo substrates of calpain. In contrast, the activity of another important antioxidant enzyme, glutathione peroxidase, is stimulated in vitro by calpain. This may explain the correlation between elevations in glutathione peroxidase activity and calpain activity which occur in aging, exercised and dystrophic muscle. Calpain treatment in vitro caused a large decrease in the activity of carnosine synthetase which is involved in the synthesis of the putative antioxidant carnosine. This may be the reason for the in vivo correlation between elevated calpain and diminished carnosine levels in aging, hypertensive, denervated and dystrophic muscles.

Determination of carnosine and other biogenic imidazoles in equine plasma by isocratic reversed-phase ion-pair high-performance liquid chromatography

The isocratic reversed-phase ion-pair high-performance liquid chromatographic technique presented provides a sensitive, rapid and reproducible analytical method for the selective determination of carnosine and other biogenic imidazoles in equine plasma. Plasma was deproteinized with 5-sulphosalicylic acid and the compounds of interest were isolated by sorbent extraction on Bond Elut PRS cartridges. Recoveries were 97–105% and the lowest limits of detection were 58.3–80.1 n M. All compounds of interest were well resolved within a maximum retention time of 9.2 min. The mean equine plasma carnosine level determined by this method was 11.31 μ M. Comparative determinations were made in canine and human plasma. Carnosine was not detected in human plasma. Concentrations of imidazole in canine plasma are reported here for the first time.

Effect of histamine antagonists on myocardial carcinine metabolism during compound [formula omitted]-induced shock

Carcinine (β-alanylhistamine) is an imidazole dipeptide that exists in mammalian hearts, increases cardiac contractility, and is metabolically linked to carnosine (β-alanylhistidine), a non-mast cell histidine and histamine precursor during stress. We have previously shown that tissue carnosine levels are regulated by H 1 and H 2 receptors. This study evaluated the effects of H 1, H 2, and mast cell degranulation blockers on metabolism of carcinine and related imidazoles during shock induced by compound 48/80, a mast cell degranulator. Fifty 125-g male Sprague-Dawley rats were divided into nine ip treatment groups: saline, 48 80 , lodoxamide (LOD, mast cell degranulation inhibitor), diphenhydramine (DPH, H 1 antagonist), cimetidine (CIM, H 2 antagonist), LOD + 48 80 , CIM + 48 80 , DPH + 48 80 , or DPH + CIM + 48 80 . Heart tissue was analyzed at 30 min by HPLC. 48 80 caused decreases in myocardial carnosine ( P < 0.01) and histidine ( P < 0.0001) levels and concomitant increases in carcinine ( P < 0.01), histamine ( P < 0.01), and 3-methylhistamine ( P < 0.05) compared to those of controls. These changes were inhibited by LOD or DPH. Treatment with CIM significantly increased myocardial carcinine levels compared to 48 80 alone ( P < 0.001) without an additional effect on the other compounds. These data indicate that carcinine is involved in the cardiac response to stress via the carnosine—histidine—histamine pathway. Compound 48 80 -induced shock increases histamine metabolism via this pathway resulting in mobilization of myocardial carnosine and histidine to carcinine and histamine; this effect is increased by H 2 receptor blockade.

Free amino acids in muscle: effect of muscle fiber population and denervation

One hindlimb of each rat was denervated by sectioning the sciatic nerve. Three days later, soleus, plantaris, and gastrocnemius muscles of the sham hindlimb and the contralateral denervated hindlimb were excised and analyzed for intracellular concentrations of 23 free amino acids and the dipeptides carnosine and anserine. Compared with the sham soleus (slow-twitch) muscle, the sham plantaris and gastrocnemius (fast-twitch) muscles showed 57-81% lower concentrations of histidine, glutamine, glutamate, aspartate, and serine and also 32-78% lower levels of taurine, citrulline, phosphoserine, and ornithine. On the other hand the fast-twitch muscles exhibited 31% higher concentrations of free glycine and alanine and 113-127% higher levels of carnosine and anserine than the soleus muscle. The denervation caused greater changes in soleus muscle than in the other two muscles. The denervation-induced changes in soleus muscle included 38-87% increases in concentrations of free valine, leucine, isoleucine, and glutamate associated with 21-56% decreases in the levels of glutamine, glycine, aspartate, serine, alanine, and citrulline. It is concluded that both muscle fiber population and muscle denervation have an independent effect on the intracellular concentrations of free amino acids in muscles.

Effect of starvation and sea-water acclimation on the concentration of free l-histidine and related dipeptides in the muscle of eel, rainbow trout and Japanese dace

1. 1. During the starvation of the eel (200 days), the rainbow trout (62 days) and the Japanese dace (75 days), white muscle free l-histidine decreased rapidly in every species, while carnosine and anserine levels in the eel and trout, respectively, exhibited relatively smaller percentage changes. 2. 2. Accompanying sea-water acclimation, l-histidine in skeletal muscle of the ell and trout increased 2- and 5-fold, respectively, but in dace muscle no significant chenge occured. The concentration of carnosine in the eel and anserine in the trout remained almost at constant levels even in sea-water.

Metabolism of L-Histidine, Carnosine, and Anserine in Skipjack Tuna

The effects of some physiological conditions on the levels of L-histidine, carnosine, and anserine were examined in skipjack tuna, Katsuwonus pelamis. Also examined were the turnover rates of L-[U-14C]histidine in skipjack blood and skeletal muscle, the metabolic interrelationship among several organs, and interconversion between histidine and the dipeptides. In white muscle of control tuna, these compounds in total occurred at a mean ± SD concentration of 147.4 ± 3.5 μmol/g muscle (n = 5) (histidine, 93.5 ± 9.2; carnosine, 2.90 ± 1.66; anserine, 51.1 ± 10.2 μmol/g muscle), but in red muscle the total concentration was only 21.3 ± 2.1 μmol/g muscle. Exhaustive burst swimming did not lead to any large changes in these concentrations, whereas starvation markedly affected them. In white muscle, histidine decreased to 30% and 4% of control levels after 5 and 12 days of starvation, respectively; carnosine increased 3.7- and 8.6-fold, while anserine decreased in the initial stage but recovered to control levels during sustained starvation. A similar pattern also was observed in red muscle. The metabolic half-life of 14C-labeled histidine was 0.72 ± 0.124 h (n = 3) in skipjack blood, and 66 and 52.5 h in white and red muscle, respectively. The label was incorporated into muscle carnosine and anserine, though the incorporation was fairly slow. The label was transported rapidly from blood into liver and muscles and also from white muscle into red.

Carnosine Synthesis in Olfactory Tissue During Ontogeny: Effect of Exogenous β‐Alanine

Carnosine has now been demonstrated by chemical analysis to be present in rat olfactory mucosa on day 16 of gestation. The tissue content of this dipeptide then increases progressively during fetal and postnatal life. Radioactive carnosine can be isolated from cultured embryonic rat olfactory mucosa incubated with [14C]beta-alanine as early as 13-14 days of gestation. The amount of incorporation also increases progressively with the initial age of the explant and with time in culture indicating in vitro maturation of the carnosine synthesis capability of olfactory tissue. To test whether the level of beta-alanine was limiting the synthesis of carnosine, we evaluated the effect of elevated beta-alanine levels on tissue carnosine content. Exogenous beta-alanine caused an increase in the tissue content of carnosine at several ages in vivo and in vitro. In adult animals this increase was observed in olfactory bulb, olfactory mucosa, and skeletal muscle. However, there was no associated alteration in carnosine synthetase activity. In addition, the different half-lives of carnosine in olfactory tissue and muscle seemed unaltered, arguing against any effect on degradative enzymes. Thus, tissue carnosine levels are regulated, at least in part, by substrate availability. The early appearance of carnosine synthetic capacity during prenatal development indicates that this enzyme activity should be a valuable aid in studying early events in olfactory neuron maturation.

Effects of neuromuscular blockers on carnosine levels in rat skeletal muscle.

A 30-min treatment with neuromuscular blocking doses of either physostigmine or d-tubocurarine was associated with a 44% or 36% (respectively) reduction in rat skeletal muscle carnosine levels in vivo.

Buffering capacity of deproteinized human vastus lateralis muscle.

The in vitro deproteinized vastus lateralis muscle buffer capacity, carnosine, and histidine levels were examined in 20 men from 4 distinct populations (5 sprinters, 800-m runners; 5 rowers; 5 marathoners; 5 untrained). Needle biopsies were obtained at rest from the vastus lateralis muscle. The buffer capacity was determined in deproteinized homogenates by repeatedly titrating supernatant extracts over the pH range of 7.0-6.0 with 0.01 N HCl. Carnosine and histidine levels were determined on an amino acid AutoAnalyzer. Fast-twitch fiber percentage was determined by staining intensity of myosin adenosinetriphosphatase. High-intensity running performance was assessed on an inclined treadmill run to fatigue (20% incline; 3.5 m X s-1). Significantly (P less than 0.01) elevated buffer capacities, carnosine levels, and high-intensity running performances were demonstrated by the sprinters and rowers, but no significant differences existed between these variables for the marathoners vs. untrained subjects. Low but significant (P less than 0.05) interrelationships were demonstrated between buffer capacity, carnosine levels, and fast-twitch fiber composition. These findings indicate that the sprinters and rowers possess elevated buffering capabilities and carnosine levels compared with marathon runners and untrained subjects.

Metabolic Effects of Histidine-Deficient Diets Fed to Growing Rats by Gastric Tube

Effects of histidine deficiency on muscle carnosine and anserine levels and on activities of enzymes associated with histidine catabolism and protoporphyrin synthesis were investigated. Male Sprague-Dawley (150 g) rats were tubefed isonitrogenous, isocaloric, defined diets containing 0%, low (0.013%) or adequate (0.45%) histidine for 8–13 days. While histidine-deficient animals maintained body weight, muscle and plasma histidine and carnosine concentrations decreased rapidly and remained low following a 3-day histidine repletion period. Hepatic histidine ammonia-lyase and histidine-pyruvate transaminase activities were decreased in histidine-deficient animals, whereas formiminotransferase activity was unchanged. Hematocrit levels and hemoglobin concentrations declined progressively during histidine depletion and the activity of erythrocyte and hepatic δ-aminolevulinic acid dehydratase also decreased relative to controls. Evidence is presented indicating that decreased histidine catabolism combined with carnosine and hemoglobin degradation can provide sufficient histidine to explain the slow onset of negative nitrogen balance associated with histidine deficiency and that impaired protoporphyrin synthesis may partially explain the anemia observed in the absence of dietary histidine.

The utilization of carnosine in rats fed on a histidine-free diet and its effect on the levels of tissue histidine and carnosine.

Carnosine can support the growth of rats fed on a histidine-free diet. Rats fed on the histidine-free diet lost weight rapidly for a few days, then remained at a relatively constant weight for 2 weeks at least. However, rats fed on a 0.90% carnosine diet, which contains histidine equimolar to that in a 20% casein diet, increased their weight at the same rate as rats fed on a 20% amino acid diet simulated with casein. On the other hand, the growth of rats fed on a 5% carnosine diet was about 70% compared with that of control rats fed on the 20% amino acid diet for a 2-week experimental period. Carnosinase activity was not significantly affected in the kidney of rats fed on the histidine-free or the 5% carnosine diet. On the other hand, carnosinase activity in the small intestine of rats fed on the histidine-free diet was significantly increased. Histidine content of serum of rats fed on the histidine-free diet decreased to 1/3 of that of control rats, while that of rats fed on the 5% carnosine diet increased to about 14 times. Carnosine content of rat gastrocnemius muscle increased with carnosine content of diets, followed by an increase of histidine in the muscle. However, carnosinase activity of gastrocnemius muscle was not affected by carnosine in diets.

A new rapid method for determination of anserine and carnosine in muscles

1. 1. It was found that anserine and carnosine form with o-phthalic aldehyde coloured reaction products of identical molar coefficient of absorption at 640 nm. Hence, a simple and rapid method for spectrophotometric determination of these dipeptides has been worked out. The method was applied to determine the sum of anserine and carnosine in muscles of adult geese, (♀). Carnosine was determined with enzymatic method. 2. 2. Ratio between anserine and carnosine concentrations depends on animal age (lower in 1-yr-old geese than in 2- and 3-yr-old ones) and type of muscles (lower in leg muscles compared to breast muscle). 3. 3. Correlation was found between level of carnosine and level of anserine—it depended both on geese and type of muscles.