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Comparative study of energetic nucleotides in young and adult trout (Salmo gairdneri R.)
91
Aquaculture,
81 (1989) 91-96 Elsevier Science Publishers B.V., Amsterdam -
Printed in The Netherlands
Comparative Study of Energetic Nucleotides in Young and Adult Trout (Salmo gairdneri R.) C. CANN-MOISAN’,
J. CAROFF’, P. SEBERT’ and L. BARTHELEMY’
‘Service de Physiologic, UA-CNRS 648, Faculti de Mkdecine, 22, Avenue Camille Desmoulins, 29285 Brest Ckdex (France) ‘Unit+3 d’Analyses Physiologiques, Service Lavoisier, CHR, 29285 Brest Ckdex (France)
(Accepted 14 January
1989 )
ABSTRACT Cann-Moisan, C., Caroff, J., Sebert, P. and Barth&my, L., 1989. Comparative study of energetic nucleotides in young and adult trout (Salmo gairdneri R. ). Aquaculture, 81: 91-96. Muscle and liver concentrations of nucleotides (adenylates, IMP) and coenzymes (NAD, NADH) were measured with a HPLC method in young trout and compared with results (previously obtained) in adults. The results show that, when compared to adults, young trout have lower values of adenylates accompanied by a higher IMP level, and lower ratios of NAD/NADH; that could mean a greater activity of AMP deaminase and a lower efficiency of the respiratory chain and oxidative phosphorylation. These results are discussed with regard to a lower participation of aerobic processes in energy production in young compared with adult trout. ABBREVIATIONS ADP, adenosine diphosphatq AMP, adenosine monophosphate; ATP, adenosine triphosphate; BM, body mass; EC, energy charge; IMP, inosine monophosphate; NAD, nicotinamide adenine dinucleotide (oxidised form); NADH, nicotinamide adenine dinucleotide (reduced form); SA, sum of adenylates.
INTRODUCTION
A means of evaluating the energetic state of a tissue is the determination of the major nucleotides and their by-products (nucleotidic coenzymes) involved in the cellular metabolic pathways (glycolysis, citric acid cycle, respiratory chain). Adenylates are particularly interesting because metabolic energy is mainly transferred via the higher energy phosphate bonds of ATP. The determination of ATP, but also of ADP and AMP (hydrolysis products of ATP), thus give information about the energy directly available to the cell. To estimate the energetic state of a tissue, instead of considering only the absolute
0 1989 Elsevier Science Publishers
B.V.
92
C.CANN-MOISANETAL.
values of every adenylic nucleotide, the sum of adenylates SA= ( [ATP] + [ ADP ] + [AMP] ), the ratio [ATP] / [ ADP] and the energy charge EC = ( [ATP ] + 0.5 [ADP ] ) /SA are often more meaningful, and, according to Atkinson (1968), the energy charge is a major factor in the regulation of pathways that produce and utilize ATP. In a recent study performed in adult trout (S&no guirdneri R.; BM = 222 + 9 g), the concentrations of different nucleotides were measured in extracts of liver and striated muscle (Cann-Moisan et al., 1989). These experiments, performed with high-performance liquid chromatography (HPLC ) , have allowed reference values to be proposed (scarce in the literature) for adult trout. Later, it appeared of interest to do the same study in young trout (BM= 7 2 0.4 g) to obtain reference values and then to compare tissue energetic states, in terms of nucleotides, for young and adult trout. These metabolic aspects of fish during maturation have a double interest: first in fundamental research and then in its application, for example to growth and nutrition. MATERIAL
AND METHODS
Animuls Young trout were obtained from a local fishery and kept in the laboratory in polyethylene tanks supplied with aerated tap-water. These tanks were placed in a room open to the outside in order to obtain the natural day-night period and water temperature variations. Experiments were performed on 12 young trout (BM=7&0,4g) atawatertemperature (T,) ofl5”C (March),apH=7.9 and an oxygen partial pressure PWO, between 150 and 160 Torr. Fishes were fasted one day before the experiment. Samples and analysis Fishes were taken out of the tank (avoiding excessive motor activity) and immediately killed by immersion in liquid nitrogen for at least 5 min. Samples of tissues-muscle: young ( W=44? 7.2 mg), adult ( W=209 2 11.7 mg); liver: young ( W= 41+ 5.9 mg), adult ( W= 2315 12.1 mg)-still frozen, were rapidly removed and stored at - 80 ’ C until the extraction of nucleotides. Tissue samples were subjected to alkaline extraction (Cann-Moisan et al., 1988) with a view to NADH determination. Briefly, the tissues were homogenized with polytron in ice KOH (0.5 N) , then centrifuged at 30 OOOg;the supernatant was sampled and its pH adjusted to 6.5 with a 1 M KH,PO, solution. For the determination of adenylates (ATP, ADP, AMP), IMP and NAD, tissue samples were acid extracted (SQbert et al., 1987). Briefly, the tissues were homogenized with polytron in ice TCA-ether (0.6 N), the nucleotides were extracted with a TCA-water mixture (10% W/V); after centrifugation at 30 OOOgthe supernatant was extracted with ether to eliminate the TCA.
93
ENERGETIC NUCLROTIDES IN YOUNG AND ADULT TROUT
Before analysis, the extracts were filtered (0.45 pm) and then injected into the HPLC system. Separation of nucleotides was achieved with gradient elution (Cann-Moisan et al., 1989) at a constant flow rate of 0.8 ml min-l on a Hypersil ODS 5 pm column (250x 4.6 mm i.d.) at 254 nm. Statistical analysis of the results was performed using a Student t-test (5% level ) .
RESULTS
Nucleotide contents of muscle and liver in young trout and those recently obtained in adults at the same season (Cann-Moisan et al., 1989) are shown in Table 1, to compare young and adults. In the liver significantly lower values (P
Muscle
Adult trout ATP ADP AMP SA EC IMP NAD NADH
1739 543 115 2398 0.83 ND 253 21
k k k k k
104.6 46.4 11.1 121.0 0.012
f +
13.5 4.8
Young trout
Adult trout
734 + 219 + 145 k 1099 + 0.75 + 230 f 162 + 116 +
3386 878 130 4415 0.85 1691 218 61
106.2** 24.2++ 26.5NS 87.4’* 0.036** 31.3++ 8.8** 13.0**
k471.8 f 73.2 f 20.1 zk485.7 f 0.021 k 414.8 f 15.3 f 11.3
Young trout 3282 f 217.2Ns 470 f 9.9** 47 + 5.5** 3799 + 208.1NS 0.92 f 0.007** 3432 f 413.2** 166 k 9.6* 86 + 5.5N.3
Results are given as mean f SEM. ND, not detected. The signiticant differences between the results obtained in young and adult trout: *P < 0.0 1; **P-c 0.001; NS, no signitkant difference.
94
C. CANN-MOISAN
ET AL.
DISCUSSION
Besides the nucleotide values proposed (very scarce in the literature), SA= ( [ATP] + [ADP] + [AMP] ) and EC= ( [ATP] +0.5 [ADP] )/SA have been calculated. The energy charge takes into account the ratio of the three adenylates: thus its determination allows estimation of the activities of ATPgenerating processes (catabolism of protein, lipids, carbohydrates) and of ATPrequiring processes (for synthesis of constitutive matter, muscular contraction, active transport of molecules). Thus the use of SA and EC gives interesting information about available energy in the form of adenylates (SA) and their energy utilization (EC), i.e. of the energy efficiency. It is well known that in fish, IMP, a deamination product of AMP, takes a prominent part in processes of energy charge stabilization during intense activity (Wieser et al., 1985; Dobson and Hochachka, 1987) or during hypoxia (Van Waarde et al., 1983; Boutilier et al., 1988). Indeed, in these conditions where the aerobic production of ATP tends to decrease, the hydrolysis of ATP to ADP and AMP activates an anaerobic metabolic pathway (glycolysis). These anaerobic processes can be accompanied by the activation of AMP deaminase (very active in fish) which catalyses the deamination of AMP to IMP, maintaining the energy charge at a high value (Van Den Thillart et al., 1980). This AMP deaminase activity is stimulated by the high level of AMP but also by H+ produced during anaerobic processes. The result is an increase of IMP and also NH3 which has a buffering effect (Van Waarde and Kesbeke, 1981): AMP
AMP+HaO
deaminase
)
IMP+NH,
The present experiment shows that in young trout placed in similar environmental conditions (T,, pH,, PwOa) to adults, there is a relatively greater production of IMP in liver and muscle. This lower participation of the aerobic process compared with adults can be explained by less efficient aerobic processes ( Wieser et al., 1985) and/or a later development of ‘red muscle” (Nag and Nursall, 1972), because red muscle has a greater capacity for oxidative metabolism than white muscle. Moreover, in this study, the values of the ratio NAD/NADH are lower in young (liver, 1.4; muscle, 2.0) than in adult trout (liver, 12.0; muscle, 3.6). This could indicate lower efficiency of the respiratory chain in young trout, whose oxygen consumption (related to body mass) is higher than in adults (Itazawa and Oikawa, 1983). Thus, to compensate for the lower efficiency of its aerobic energy production, the young trout must increase the participation of its anaerobic processes. The IMP production gives evidence of the participation of metabolic processes to maintain the energy charge at a good level. In muscle, these processes could be the increased activity of the myokinase (2 ADP e ATP + AMP ) associated
ENERGETICNlJCLEOTIDESINYOUNGANDADULTTROUT
95
with AMP deaminase: in these conditions, the energy charge stays at a relatively high value (0.92 ) whereas the adenylate pool is low in comparison to adults. In liver, with regard to the SA and EC values, it appears that energy stores are lower in the young than in the adult. As in muscle, aerobic processes are less active in the young (NAD/NADH: adult, 12; young, 1.4), and IMP (not detected in adult liver) is high in the young. The differences observed between the metabolic efficiency of liver and muscle (liver: EC young < EC adult; muscle: EC young> EC adult) during maturation could be explained by the higher amount of phosphocreatine and by a faster turnover of ATP in muscle (Dobson and Hochachka, 1987) with a greater participation of AMP deaminase in muscle than in liver (Van Den Thillart et al., 1980). Thus it appears that in young trout, compared with adults, relatively greater activation of adenylate kinase and AMP deaminase are necessary to maintain the energy charge at high values. This result is in agreement with Wieser et al. (1985) who observed that in young trout, aerobic participation during muscular activity increases with age and size while anaerobic energy production is unaffected by these biometric parameters. In contrast, the large energetic needs of the young for endergonic synthesis would be at least in part responsible for the low level of the adenylate pool (SA) when compared with adults. In conclusion, this study brings more precise knowledge of the energetic metabolism of the fish and of the development of tissular nucleotide contents at two stages of maturation. Such results are applicable to aquaculture:the growth of an animal necessitates consumption of foods which must be sufficient so that ATP, generated from the catabolism of food, insures the living functions of the animal but also the elaboration of constitutive matter. Interest in knowing the energetic state of a tissue, evaluated by EC and SA, is then evident. These biochemical indices have also been used by other authors in pollution monitoring (Viarengo et al., 1986) or as indicators of hypoxic stress (Vetter and Hodson, 1982 ).
REFERENCES
Atkinson, D.E., 1968. The energy charge of the adenylate pool as a regulatory parameter. Interaction with feedback modifiers. Biochemistry, 7: 4030-4034. Boutilier, R.G., Dobson, G., Hoeger, U. andRandall, D.J., 1988. Acute exposure to graded levels of hypoxia in rainbow trout (Salmo gairdneri): metabolic and respiratory adaptations. Respir. Physiol., 71: 69-82. Cann-Moisan, C., Sbbert, P., Caroff, J. and Barth&my, L., 1988. Effects of hydrostatic pressure (HP = 101 ATA) on nucleotides and pyridine dinucleotides tissue contents in trout. Exp. Biol., 47: 239-242. Cann-Moisan, C., Caroff, J., Sebert, P. and Barth&my, L., 1989. Determination of nucleotide
96
C. CANN-MOISAN
El’ AL.
concentrations with high performance liquid chromatography (HPLC): application to fish. Aquaculture, 76: 135-143. Dobson, G.P. and Hochachka, P.W., 1987. Role of glycolysis in adenylate depletion and repletion during work and recovery in teleost white muscle. J. Exp. Bioi., 129: 125-140. Itaxawa, Y. and Oikawa, S., 1983. Metabolic rates in excised tissues of carp. Experientia, 39: 160161. Nag, AC. and Nursall, J.R., 1972. Histogenesis of white and red muscle fibres of trunk muscles of a fish, Salmo gairdneri. Cytobios, 6: 227-246. Slbert, P., Barth&my, L., Caroff, J. and Hourman t, A., 1987. Effects of hydrostatic pressure “per se” (101 ATA) on energetic processes in fish. Comp. Biochem. Physiol., 86A: 491-495. Van Den Thihart, G., Kesbeke, F. and Van Waarde, A., 1980. Anaerobic energy metabolism of goldfish, Care&us auratus (IL.). Influence of hypoxia and anoxia on phosphorylated compounds and glycogen. J. Comp. Physiol., 136: 45-52. Van Waarde, A. and Kesbeke, F., 1981. Regulatory properties of AMP deaminase from lateral red muscle and dorsal white muscle of goldfish, CarassiLls auratus (L.). Comp. Biochem. Physiol., 69B: 413-423. Van Waarde, A., Van Den Thillart, G. and Kesbeke, F., 1983. Anaerobic energy metabolism of the European eel, Anguilh anguilla (L. ), J. Comp. Physiol., 149: 469-475. Vetter, R.D. and Hodson, R.E., 1982. Use of adenylate concentrations and adenylate energy charge as indicators of hypoxic stress in estuarine fish. Can. J. Fish. Aquat. Sci., 39: 535-541. Viarengo, A., Secondini, A., Scoppa, P. and Orunesu, M., 1986. A rapid HPLC method for determination of adenylate energy charge. Experientia, 42: 1234-1235. Wieser, W., Platser, U. and Hinterleitner, S., 1985. Anaerobic and aerobic energy production of young rainbow trout (Salmo gairdneri) during and after bursts of activity. J. Comp. Physiol., 155B: 485-492.
Aquaculture,
81 (1989) 91-96 Elsevier Science Publishers B.V., Amsterdam -
Printed in The Netherlands
Comparative Study of Energetic Nucleotides in Young and Adult Trout (Salmo gairdneri R.) C. CANN-MOISAN’,
J. CAROFF’, P. SEBERT’ and L. BARTHELEMY’
‘Service de Physiologic, UA-CNRS 648, Faculti de Mkdecine, 22, Avenue Camille Desmoulins, 29285 Brest Ckdex (France) ‘Unit+3 d’Analyses Physiologiques, Service Lavoisier, CHR, 29285 Brest Ckdex (France)
(Accepted 14 January
1989 )
ABSTRACT Cann-Moisan, C., Caroff, J., Sebert, P. and Barth&my, L., 1989. Comparative study of energetic nucleotides in young and adult trout (Salmo gairdneri R. ). Aquaculture, 81: 91-96. Muscle and liver concentrations of nucleotides (adenylates, IMP) and coenzymes (NAD, NADH) were measured with a HPLC method in young trout and compared with results (previously obtained) in adults. The results show that, when compared to adults, young trout have lower values of adenylates accompanied by a higher IMP level, and lower ratios of NAD/NADH; that could mean a greater activity of AMP deaminase and a lower efficiency of the respiratory chain and oxidative phosphorylation. These results are discussed with regard to a lower participation of aerobic processes in energy production in young compared with adult trout. ABBREVIATIONS ADP, adenosine diphosphatq AMP, adenosine monophosphate; ATP, adenosine triphosphate; BM, body mass; EC, energy charge; IMP, inosine monophosphate; NAD, nicotinamide adenine dinucleotide (oxidised form); NADH, nicotinamide adenine dinucleotide (reduced form); SA, sum of adenylates.
INTRODUCTION
A means of evaluating the energetic state of a tissue is the determination of the major nucleotides and their by-products (nucleotidic coenzymes) involved in the cellular metabolic pathways (glycolysis, citric acid cycle, respiratory chain). Adenylates are particularly interesting because metabolic energy is mainly transferred via the higher energy phosphate bonds of ATP. The determination of ATP, but also of ADP and AMP (hydrolysis products of ATP), thus give information about the energy directly available to the cell. To estimate the energetic state of a tissue, instead of considering only the absolute
0 1989 Elsevier Science Publishers
B.V.
92
C.CANN-MOISANETAL.
values of every adenylic nucleotide, the sum of adenylates SA= ( [ATP] + [ ADP ] + [AMP] ), the ratio [ATP] / [ ADP] and the energy charge EC = ( [ATP ] + 0.5 [ADP ] ) /SA are often more meaningful, and, according to Atkinson (1968), the energy charge is a major factor in the regulation of pathways that produce and utilize ATP. In a recent study performed in adult trout (S&no guirdneri R.; BM = 222 + 9 g), the concentrations of different nucleotides were measured in extracts of liver and striated muscle (Cann-Moisan et al., 1989). These experiments, performed with high-performance liquid chromatography (HPLC ) , have allowed reference values to be proposed (scarce in the literature) for adult trout. Later, it appeared of interest to do the same study in young trout (BM= 7 2 0.4 g) to obtain reference values and then to compare tissue energetic states, in terms of nucleotides, for young and adult trout. These metabolic aspects of fish during maturation have a double interest: first in fundamental research and then in its application, for example to growth and nutrition. MATERIAL
AND METHODS
Animuls Young trout were obtained from a local fishery and kept in the laboratory in polyethylene tanks supplied with aerated tap-water. These tanks were placed in a room open to the outside in order to obtain the natural day-night period and water temperature variations. Experiments were performed on 12 young trout (BM=7&0,4g) atawatertemperature (T,) ofl5”C (March),apH=7.9 and an oxygen partial pressure PWO, between 150 and 160 Torr. Fishes were fasted one day before the experiment. Samples and analysis Fishes were taken out of the tank (avoiding excessive motor activity) and immediately killed by immersion in liquid nitrogen for at least 5 min. Samples of tissues-muscle: young ( W=44? 7.2 mg), adult ( W=209 2 11.7 mg); liver: young ( W= 41+ 5.9 mg), adult ( W= 2315 12.1 mg)-still frozen, were rapidly removed and stored at - 80 ’ C until the extraction of nucleotides. Tissue samples were subjected to alkaline extraction (Cann-Moisan et al., 1988) with a view to NADH determination. Briefly, the tissues were homogenized with polytron in ice KOH (0.5 N) , then centrifuged at 30 OOOg;the supernatant was sampled and its pH adjusted to 6.5 with a 1 M KH,PO, solution. For the determination of adenylates (ATP, ADP, AMP), IMP and NAD, tissue samples were acid extracted (SQbert et al., 1987). Briefly, the tissues were homogenized with polytron in ice TCA-ether (0.6 N), the nucleotides were extracted with a TCA-water mixture (10% W/V); after centrifugation at 30 OOOgthe supernatant was extracted with ether to eliminate the TCA.
93
ENERGETIC NUCLROTIDES IN YOUNG AND ADULT TROUT
Before analysis, the extracts were filtered (0.45 pm) and then injected into the HPLC system. Separation of nucleotides was achieved with gradient elution (Cann-Moisan et al., 1989) at a constant flow rate of 0.8 ml min-l on a Hypersil ODS 5 pm column (250x 4.6 mm i.d.) at 254 nm. Statistical analysis of the results was performed using a Student t-test (5% level ) .
RESULTS
Nucleotide contents of muscle and liver in young trout and those recently obtained in adults at the same season (Cann-Moisan et al., 1989) are shown in Table 1, to compare young and adults. In the liver significantly lower values (P
Muscle
Adult trout ATP ADP AMP SA EC IMP NAD NADH
1739 543 115 2398 0.83 ND 253 21
k k k k k
104.6 46.4 11.1 121.0 0.012
f +
13.5 4.8
Young trout
Adult trout
734 + 219 + 145 k 1099 + 0.75 + 230 f 162 + 116 +
3386 878 130 4415 0.85 1691 218 61
106.2** 24.2++ 26.5NS 87.4’* 0.036** 31.3++ 8.8** 13.0**
k471.8 f 73.2 f 20.1 zk485.7 f 0.021 k 414.8 f 15.3 f 11.3
Young trout 3282 f 217.2Ns 470 f 9.9** 47 + 5.5** 3799 + 208.1NS 0.92 f 0.007** 3432 f 413.2** 166 k 9.6* 86 + 5.5N.3
Results are given as mean f SEM. ND, not detected. The signiticant differences between the results obtained in young and adult trout: *P < 0.0 1; **P-c 0.001; NS, no signitkant difference.
94
C. CANN-MOISAN
ET AL.
DISCUSSION
Besides the nucleotide values proposed (very scarce in the literature), SA= ( [ATP] + [ADP] + [AMP] ) and EC= ( [ATP] +0.5 [ADP] )/SA have been calculated. The energy charge takes into account the ratio of the three adenylates: thus its determination allows estimation of the activities of ATPgenerating processes (catabolism of protein, lipids, carbohydrates) and of ATPrequiring processes (for synthesis of constitutive matter, muscular contraction, active transport of molecules). Thus the use of SA and EC gives interesting information about available energy in the form of adenylates (SA) and their energy utilization (EC), i.e. of the energy efficiency. It is well known that in fish, IMP, a deamination product of AMP, takes a prominent part in processes of energy charge stabilization during intense activity (Wieser et al., 1985; Dobson and Hochachka, 1987) or during hypoxia (Van Waarde et al., 1983; Boutilier et al., 1988). Indeed, in these conditions where the aerobic production of ATP tends to decrease, the hydrolysis of ATP to ADP and AMP activates an anaerobic metabolic pathway (glycolysis). These anaerobic processes can be accompanied by the activation of AMP deaminase (very active in fish) which catalyses the deamination of AMP to IMP, maintaining the energy charge at a high value (Van Den Thillart et al., 1980). This AMP deaminase activity is stimulated by the high level of AMP but also by H+ produced during anaerobic processes. The result is an increase of IMP and also NH3 which has a buffering effect (Van Waarde and Kesbeke, 1981): AMP
AMP+HaO
deaminase
)
IMP+NH,
The present experiment shows that in young trout placed in similar environmental conditions (T,, pH,, PwOa) to adults, there is a relatively greater production of IMP in liver and muscle. This lower participation of the aerobic process compared with adults can be explained by less efficient aerobic processes ( Wieser et al., 1985) and/or a later development of ‘red muscle” (Nag and Nursall, 1972), because red muscle has a greater capacity for oxidative metabolism than white muscle. Moreover, in this study, the values of the ratio NAD/NADH are lower in young (liver, 1.4; muscle, 2.0) than in adult trout (liver, 12.0; muscle, 3.6). This could indicate lower efficiency of the respiratory chain in young trout, whose oxygen consumption (related to body mass) is higher than in adults (Itazawa and Oikawa, 1983). Thus, to compensate for the lower efficiency of its aerobic energy production, the young trout must increase the participation of its anaerobic processes. The IMP production gives evidence of the participation of metabolic processes to maintain the energy charge at a good level. In muscle, these processes could be the increased activity of the myokinase (2 ADP e ATP + AMP ) associated
ENERGETICNlJCLEOTIDESINYOUNGANDADULTTROUT
95
with AMP deaminase: in these conditions, the energy charge stays at a relatively high value (0.92 ) whereas the adenylate pool is low in comparison to adults. In liver, with regard to the SA and EC values, it appears that energy stores are lower in the young than in the adult. As in muscle, aerobic processes are less active in the young (NAD/NADH: adult, 12; young, 1.4), and IMP (not detected in adult liver) is high in the young. The differences observed between the metabolic efficiency of liver and muscle (liver: EC young < EC adult; muscle: EC young> EC adult) during maturation could be explained by the higher amount of phosphocreatine and by a faster turnover of ATP in muscle (Dobson and Hochachka, 1987) with a greater participation of AMP deaminase in muscle than in liver (Van Den Thillart et al., 1980). Thus it appears that in young trout, compared with adults, relatively greater activation of adenylate kinase and AMP deaminase are necessary to maintain the energy charge at high values. This result is in agreement with Wieser et al. (1985) who observed that in young trout, aerobic participation during muscular activity increases with age and size while anaerobic energy production is unaffected by these biometric parameters. In contrast, the large energetic needs of the young for endergonic synthesis would be at least in part responsible for the low level of the adenylate pool (SA) when compared with adults. In conclusion, this study brings more precise knowledge of the energetic metabolism of the fish and of the development of tissular nucleotide contents at two stages of maturation. Such results are applicable to aquaculture:the growth of an animal necessitates consumption of foods which must be sufficient so that ATP, generated from the catabolism of food, insures the living functions of the animal but also the elaboration of constitutive matter. Interest in knowing the energetic state of a tissue, evaluated by EC and SA, is then evident. These biochemical indices have also been used by other authors in pollution monitoring (Viarengo et al., 1986) or as indicators of hypoxic stress (Vetter and Hodson, 1982 ).
REFERENCES
Atkinson, D.E., 1968. The energy charge of the adenylate pool as a regulatory parameter. Interaction with feedback modifiers. Biochemistry, 7: 4030-4034. Boutilier, R.G., Dobson, G., Hoeger, U. andRandall, D.J., 1988. Acute exposure to graded levels of hypoxia in rainbow trout (Salmo gairdneri): metabolic and respiratory adaptations. Respir. Physiol., 71: 69-82. Cann-Moisan, C., Sbbert, P., Caroff, J. and Barth&my, L., 1988. Effects of hydrostatic pressure (HP = 101 ATA) on nucleotides and pyridine dinucleotides tissue contents in trout. Exp. Biol., 47: 239-242. Cann-Moisan, C., Caroff, J., Sebert, P. and Barth&my, L., 1989. Determination of nucleotide
96
C. CANN-MOISAN
El’ AL.
concentrations with high performance liquid chromatography (HPLC): application to fish. Aquaculture, 76: 135-143. Dobson, G.P. and Hochachka, P.W., 1987. Role of glycolysis in adenylate depletion and repletion during work and recovery in teleost white muscle. J. Exp. Bioi., 129: 125-140. Itaxawa, Y. and Oikawa, S., 1983. Metabolic rates in excised tissues of carp. Experientia, 39: 160161. Nag, AC. and Nursall, J.R., 1972. Histogenesis of white and red muscle fibres of trunk muscles of a fish, Salmo gairdneri. Cytobios, 6: 227-246. Slbert, P., Barth&my, L., Caroff, J. and Hourman t, A., 1987. Effects of hydrostatic pressure “per se” (101 ATA) on energetic processes in fish. Comp. Biochem. Physiol., 86A: 491-495. Van Den Thihart, G., Kesbeke, F. and Van Waarde, A., 1980. Anaerobic energy metabolism of goldfish, Care&us auratus (IL.). Influence of hypoxia and anoxia on phosphorylated compounds and glycogen. J. Comp. Physiol., 136: 45-52. Van Waarde, A. and Kesbeke, F., 1981. Regulatory properties of AMP deaminase from lateral red muscle and dorsal white muscle of goldfish, CarassiLls auratus (L.). Comp. Biochem. Physiol., 69B: 413-423. Van Waarde, A., Van Den Thillart, G. and Kesbeke, F., 1983. Anaerobic energy metabolism of the European eel, Anguilh anguilla (L. ), J. Comp. Physiol., 149: 469-475. Vetter, R.D. and Hodson, R.E., 1982. Use of adenylate concentrations and adenylate energy charge as indicators of hypoxic stress in estuarine fish. Can. J. Fish. Aquat. Sci., 39: 535-541. Viarengo, A., Secondini, A., Scoppa, P. and Orunesu, M., 1986. A rapid HPLC method for determination of adenylate energy charge. Experientia, 42: 1234-1235. Wieser, W., Platser, U. and Hinterleitner, S., 1985. Anaerobic and aerobic energy production of young rainbow trout (Salmo gairdneri) during and after bursts of activity. J. Comp. Physiol., 155B: 485-492.