Alterations in glucose metabolism in chick embryo cells transformed by Rous sarcoma virus. Transformation-specific changes in the activities of key enzymes of the glycolytic and hexose monophosphate shunt pathways

Effects of transformation by Rous sarcoma virus of Schmidt-Ruppin strain on the activities of key enzymes of the glycolytic and the hexose monophosphate shunt pathways in chick-embryo cells were investigated. Activities of hexokinase, phosphofructokinase, pyruvate kinase, lactate dehydrogenase, and glucose-6-P dehydrogenase were increased about twofold in the transformed cells, but that of 6-P-gluconate dehydrogenase remained unaltered. The transformation-mediated increase in the activity of hexokinase was confined entirely to the bound form of the enzyme. Cells infected with a temperature-sensitive mutant (Ts-68) of Schmidt-Ruppin strain of Rous sarcoma virus showed the typical increase in the rate of 2-deoxyglucose uptake and the activities of hexokinase, phosphofructokinase, pyruvate kinase, and glucose-6-P dehydrogenase at the permissive temperature (37 °C), but when the infected cells were grown at the nonpermissive temperature (41 °C), the increases in the sugar uptake and activities of these enzymes were abolished. Unlike the regulatory enzymes, lactate dehydrogenase activity was increased at both the permissive and the nonpermissive temperatures.     

Role of glycerol 3-phosphate dehydrogenase in glyceride metabolism. Effect of diet on enzyme activities in chicken liver.

1. The metabolic role of hepatic NAD-linked glycerol 3-phosphate dehydrogenase (EC 1.1.1.8) was investigated vis-a-vis glyceride synthesis, glyceride degradation and the maintainence of the NAD redox state. 2. Five-week-old chickens were placed on five dietary regimes: a control group, a group on an increased-carbohydrate-lowered-fat diet, a group on a high-fat-lowered-carbohydrate diet, a starved group and a starved-refed group. In each group the specific activity (mumol/min per g wet wt. of tissue) of hepatic glycerol 3-phosphate dehydrogenase was compared with the activities of the beta-oxoacyl-(acyl-carrier protein) reductase component of fatty acid synthetase, glycerol kinase (EC 2.7.1.30) and lactate dehydrogenase (EC 1.1.1.27). 3. During starvation, the activities of glycerol 3-phosphate dehydrogenase, glycerol kinase and lactate dehydrogenase rose significantly. After re-feeding these activities returned to near normal. All three activities rose slightly on the high-fat diet. Lactate dehydrogenase activity rose slightly, whereas those of the other two enzymes fell slightly on the increased-carbohydrate-lowered-fat diet. 4. The activity of the beta-oxoacyl-(acyl-carrier protein) reductase component of fatty acid synthetase, a lipid-synthesizing enzyme, contrasted strikingly with the other three enzyme activities. Its activity was slightly elevated on the increased-carbohydrate diet and significantly diminished on the high-fat diet and during starvation. 5. The changes in activity of the chicken liver isoenzyme of glycerol 3-phosphate dehydrogenase in response to dietary stresses suggest that the enzyme has an important metabolic role other than or in addition to glyceride biosynthesis.     

Biochemical factors limiting myocardial energy in a chicken genotype selected for rapid growth.

Broiler chickens (Gallus gallus) genetically selected for rapid growth are inherently predisposed to heart failure. In order to understand the biochemical mechanisms associated with the deterioration of heart function and development of congestive heart failure (CHF) in fast-growing chickens, this study examined several factors critical for myocardial energy metabolism. Measured variables included cardiac energy substrates [creatine phosphate (CrP), adenosine triphosphate (ATP), l-carnitine], activity of selected cytosolic enzymes [creatine kinase (CK; EC 2.7.3.2), lactate dehydrogenase (LDH; EC 1.1.1.27)] and mitochondrial enzymes [pyruvate dehydrogenase (PDH; EC 1.2.4.1), alpha-ketoglutarate dehydrogenase (alpha-KGDH; EC 1.2.4.2)]. The CK activities were higher in fast-growing and CHF broilers as compared to slow-growing broilers (p<0.05). Cardiac LDH and alpha-KGDH activities were not changed (p>0.05), whereas PDH activity was highest (p<0.05) in broilers with CHF. Deterioration of heart function is correlated with lowered cardiac ATP, CrP, and l-carnitine levels (all p<0.05). Depletion of high energy phosphate substrates, ATP and CrP, is evident in fast-growing chickens and those that developed CHF. Increased activity of CK suggests that cardiac energy management in fast-growing broilers and those with CHF largely depends on contribution of this pathway to regeneration of ATP from CrP. In this scenario, inadequate level of CrP is a direct cause of ATP insufficiency, whereas low cardiac l-carnitine, because of its role in fatty acid transport, is most likely an important factor contributing to shortage of key substrate required for synthesis of cardiac ATP. The insufficiencies in cardiac energy substrate synthesis provide metabolic basis of myocardial dysfunction in chickens predisposed to heart failure.     

Biochemical factors limiting myocardial energy in a chicken genotype selected for rapid growth

Broiler chickens (Gallus gallus) genetically selected for rapid growth are inherently predisposed to heart failure. In order to understand the biochemical mechanisms associated with the deterioration of heart function and development of congestive heart failure (CHF) in fast-growing chickens, this study examined several factors critical for myocardial energy metabolism. Measured variables included cardiac energy substrates [creatine phosphate (CrP), adenosine triphosphate (ATP), l-carnitine], activity of selected cytosolic enzymes [creatine kinase (CK; EC 2.7.3.2), lactate dehydrogenase (LDH; EC 1.1.1.27)] and mitochondrial enzymes [pyruvate dehydrogenase (PDH; EC 1.2.4.1), alpha-ketoglutarate dehydrogenase (alpha-KGDH; EC 1.2.4.2)]. The CK activities were higher in fast-growing and CHF broilers as compared to slow-growing broilers (p<0.05). Cardiac LDH and alpha-KGDH activities were not changed (p>0.05), whereas PDH activity was highest (p<0.05) in broilers with CHF. Deterioration of heart function is correlated with lowered cardiac ATP, CrP, and l-carnitine levels (all p<0.05). Depletion of high energy phosphate substrates, ATP and CrP, is evident in fast-growing chickens and those that developed CHF. Increased activity of CK suggests that cardiac energy management in fast-growing broilers and those with CHF largely depends on contribution of this pathway to regeneration of ATP from CrP. In this scenario, inadequate level of CrP is a direct cause of ATP insufficiency, whereas low cardiac l-carnitine, because of its role in fatty acid transport, is most likely an important factor contributing to shortage of key substrate required for synthesis of cardiac ATP. The insufficiencies in cardiac energy substrate synthesis provide metabolic basis of myocardial dysfunction in chickens predisposed to heart failure.     

A comparative study of enzyme profile of camel (Camelus dromedarius) hump and sheep (Ovis aries) tail tissues

1. The activities of phosphoenolpyruvate carboxykinase, malic enzyme, NAD+ and NADP+ isocitrate isocitrate dehydrogenase, glucose-6-phosphate dehydrogenase, lactate dehydrogenase and pyruvate kinase were assayed in homogenate of camel hump and sheep tail tissues. 2. In addition the levels of glucose, cholesterol, total protein and total lipids in these tissues were measured. 3. Results obtained were utilized to compare the state of metabolism of adipose tissue of camel hump to that of sheep tail, and to shed some light on possible contribution of these tissues toward blood glucose level.     

A comparative study of glycolysis in red and white muscles of the trout (Salmo gairdneri) and mirror carp (Cyprinus carpio)

The activities of some glycolytic and associated enzymes have been determined in the muscles of trout and carp to investigate the possibility that the discrepancies previously reported between lactate accumulation and anoxic tolerance in these two fish result from underlying differences in glycolytic potential. Steady state concentrations of certain glycolytic intermediates were also determined in freeze-clamped muscles from tankrested fish. The activities of hexokinase, phosphorylase and phosphofructokinase were approximately 2–3 times lower in carp than trout white muscles. Pyruvate kinase and lactate dehydrogenase activities were 5 times lower in carp white muscle. The lower, broader pH optima of lactate dehydrogenase and pyruvate kinase from carp compared to trout muscles is thought to be correlated with the greater anoxic tolerance of the carp. Glycolytic enzyme profiles were markedly different between the red and white muscles of the rainbow trout but broadly similar, with the exception of hexokinase activity, for the corresponding muscles of the carp. The results are discussed in relation to what is known about anaerobiosis in these two species and the comparative physiology of red and white muscles in fish.     

Rifampicin resistance and mutation of the rpoB gene in Mycobacterium tuberculosis

Abstract The bradyzoite and tachyzoite forms of Toxoplasma gondii , purified from infected animals, were analysed for their activities of phosphofructokinase, pyruvate kinase, lactate dehydrogenase, NAD⁺- and NADH-linked isocitrate dehydrogenases, and succinic dehydrogenase. Both developmental stages contained high activities of phosphofructokinase (specific for pyrophosphate rather than ATP), pyruvate kinase and lactate dehydrogenase, suggesting that energy metabolism in both forms may centre around a high glycolytic flux linked to lactate production. The markedly higher activity of the latter two enzymes in bradyzoites suggests that lactate production is particularly important in this developmental form. NAD⁺-specific isocitrate dehydrogenase was not detectable in either stage of the parasite (and proved useful as a measure of the purity of the bradyzoite preparation), whereas both parasite forms contained low activities of NADP⁺-linked isocitrate dehydrogenase. The results are consistent with the bradyzoites lacking a functional TCA cycle and respiratory chain and are suggestive of a lack of susceptibility of this developmental stage to atovaquone.     

The levels of creatine kinase and adenylate kinase in the plasma of dystrophic chickens reflect the rates of loss of these enzymes from the circulation

The rates of loss of adenylate kinase and creatine kinase from the circulation after intravenous injection of homogenous chicken skeletal muscle enzymes were examined to determine the role of plasma clearance rates in determining the plasma levels of these enzymes in normal and dystrophic chickens. The rapid clearance of adenylate kinase activity (average half-life of 5 min) and the slower biphasic clearance of creatine kinase activity (average half-lives of 0.95 and 11 hr) are consistent with the elevation of creatine kinase but not adenylate kinase in the blood plasma of dystrophic chickens compared to normal chickens. The rates of clearance of these enzymes were similar in normal chickens compared to dystrophic chickens. Radioiodinated enzymes were cleared at similar, but slightly more rapid rates than the loss of enzyme activity. The loss of adenylate kinase activity from the circulation may be due in part to inactivation since adenylate kinase activity is rapidly inactivated in serum in vitro, and because no increase in adenylate kinase activity is observed in the most specific sites of clearance of the radioiodinated enzyme, the liver and spleen. The comparison of enzyme activities in press juices to the activities in high-ionic-strength homogenates of muscle tissue from normal and dystrophic muscle, indicates that adenylate kinase activity is not associated with intracellular structures to the extent that would prohibit release from dystrophic muscle tissue. These results, and those presented previously with regard to plasma levels and clearance rates of AMP aminohydrolase and pyruvate kinase in normal and dystrophic chickens (11) support our hypothesis that the rates of loss of muscle enzyme activities from the circulation are important in determining the circulating levels of muscle enzymes in dystrophic chickens. Furthermore, from the measurement of plasma levels and clearance rates of creatine kinase, it was estimated that the efflux rate of creatine kinase from dystrophic muscle tissue is 2.0% of the total breast muscle creatine kinase per day.     

Observations on the Taiwanese Strain of Leucocytozoon caulleryi (Haemosporina) in Chickens

ABSTRACT. The Taiwanese strain of Leucocytozoon caulleryi was isolated from an infected chicken in Taipei, Taiwan, and established in chickens and biting midges Culicoides arakawae from Japan. Sporogony of the strain in C. arakawae was completed on day 3 after the infective blood meals at 25°C. Sporozoites isolated from the salivary glands of C. arakawae on days 3 or 4 after feeding caused infection in all the chickens inoculated. The strain showed high pathogenicity for chickens. Mortality of chickens rose with an increase in the number of sporozoites inoculated. The prepatent period for chickens inoculated with sporozoites was 14 days. Parasites appeared in the peripheral blood of chickens on day 15 and disappeared on day 26 after sporozoite inoculation. Soluble antigens were found in the sera of chickens infected with the strain between 10 and 17 days after inoculation, and homologous antibodies appeared after 17 days. Antigens prepared from sera, schizonts, merozoites, and gametocytes of the Taiwanese strain reacted with the sera of chickens infected witt the same strain or the strain isolated in Japan. The chickens that recovered from a primary infection with the Taiwanese strain demonstrated complete resistance to reinfection with the same strain or the strain isolated in Japan.     

Observations on the Taiwanese strain of Leucocytozoon caulleryi (Haemosporina) in chickens

The Taiwanese strain of Leucocytozoon caulleryi was isolated from an infected chicken in Taipei, Taiwan, and established in chickens and biting midges Culicoides arakawae from Japan. Sporogony of the strain in C. arakawae was completed on day 3 after the infective blood meals at 25 degrees C. Sporozoites isolated from the salivary glands of C. arakawae on days 3 or 4 after feeding caused infection in all the chickens inoculated. The strain showed high pathogenicity for chickens. Mortality of chickens rose with an increase in the number of sporozoites inoculated. The prepatent period for chickens inoculated with sporozoites was 14 days. Parasites appeared in the peripheral blood of chickens on day 15 and disappeared on day 26 after sporozoite inoculation. Soluble antigens were found in the sera of chickens infected with the strain between 10 and 17 days after inoculation, and homologous antibodies appeared after 17 days. Antigens prepared from sera, schizonts, merozoites, and gametocytes of the Taiwanese strain reacted with the sera of chickens infected with the same strain or the strain isolated in Japan. The chickens that recovered from a primary infection with the Taiwanese strain demonstrated complete resistance to reinfection with the same strain or the the strain isolated in Japan.     

The effects of feed restriction on plasma biochemistry in growing meat type chickens (Gallus gallus)

The effect of feed restriction on plasma hormones (triiodothyronine - T(3), thyroxine - T(4), and corticosterone), protein, lipid, carbohydrate, and mineral metabolism and activity of plasma enzymes (creatine kinase, alkaline phosphatase, aspartate aminotransferase, and alanine aminotransferase) were studied in meat type female chickens (Gallus gallus). Ad libitum fed birds were compared with those subjected to severe and moderate quantitative feed restriction from 16 to 100 days of age. Feed restriction elevated plasma T(4) and corticosterone levels and reduced T(3). A feed restriction-induced decrease was observed for plasma protein and albumin concentrations, but not for uric acid and creatinine. Total plasma lipids, triacylglycerols, cholesterol, high density lipids, and calcium were lower for the feed restricted chickens, in particular during the latter phase of the experiment. Concentrations of glucose and phosphorus were not altered by feeding treatment. Activity of alkaline phosphatase was significantly increased in restricted chicks from day 58. Significant changes of plasma biochemical parameters induced by severe and moderate quantitative feed restriction illustrate that limiting feed intake poses an intensive stress on meat type chickens during the rapid growth period. However, activities of creatine kinase, aspartate aminotransferase, and alanine aminotransferase were significantly higher in ad libitum fed chickens during this period. This elevation in enzymatic activity may be in response to tissue damage, indicating potential health and welfare problems also in ad libitum fed meat type chickens, resulting from selection for intensive growth.     

Intestinal disaccharidases and some renal enzymes in streptozotocin-induced diabetic rats fed sapogenin extract from bitter yam (Dioscorea polygonoides)

In this study, the effects of bitter yam sapogenin extract or commercial diosgenin on intestinal disaccharidases and some renal enzymes in diabetic rats were investigated. Diabetic male Wistar rats were fed diets supplemented with 1% sapogenin extract or commercial diosgenin for 3 weeks. Plasma glucose, intestinal disaccharidases and the activities of transaminases, acid phosphatase, glucose-6-phosphatase, ATP citrate lyase, glucose-6-phosphate dehydrogenase and pyruvate kinase were assessed for the level of metabolic changes in the kidney of diabetic rats. Sapogenin extract or commercial diosgenin supplementation resulted in a significant decrease in lactase and maltase activities in all three regions of the intestine compared to the diabetic control group. However, the test diets significantly reduced intestinal sucrase activity in the proximal and mid regions. Test diets supplementation resulted in a significant decrease in the activities of the transaminases compared to the normal and diabetic control groups. The activity of glucose-6-phosphatase was significantly increased while the activities of ATP citrate lyase, pyruvate kinase and glucose-6-phosphate dehydrogenase were significantly reduced in the kidney of the diabetic control rats compared to the normal group. Test diets supplementation did not significantly alter glucose-6-phosphatase, ATP citrate lyase and pyruvate kinase activities compared to the diabetic control. However, there was a significant increase in glucose-6-phosphate dehydrogenase activity toward the normal group. In conclusion, the consumption of bitter yam sapogenin extract or commercial diosgenin demonstrated hypoglycemic properties, which are beneficial in diabetes by reducing intestinal disaccharidases activities; however, bitter yam sapogenin extract may adversely affect the integrity of kidney membrane.     

Effects of training and methandrostenolone (an anabolic steroid) on energy metabolism in the guinea pig: changes in enzyme activities in gastrocnemius muscle and myocardium

Modifications of enzyme activities (creatine kinase and its B subunit; adenylate kinase; hexokinase; phosphofructokinase; lactate dehydrogenase; malate dehydrogenase, isocitrate dehydrogenase; citrate synthase; acetylcarnitine transferase; beta-hydroxyacetyl-CoA dehydrogenase; cytochrome c oxidase) in gastrocnemius muscle and myocardium were reported after two forms of training with or without administration of anabolic steroid. Endurance training was on a horizontal motor-driven treadmill, 2 km X hr-1, 5 days a week for 0.5 hr per day for 5 weeks. In the case of power endurance training there was a slope of 45 degrees. Enzyme activities in controls and treated guinea pigs, as well as treatment-induced enzyme activity changes are time dependent. Some of these activities correlate linearly with one another; such correlations characterize the effect of adaptation. Endurance training and power endurance training in this study induce similar modifications and seem to differ essentially in the daily work load. The anabolic steroid methandrostenolone (dianabol) induces modifications which training does not bring about but which training at least partially eliminates.     

Effect of photoinhibitory treatments on the activity of light-activated enzymes of c(3) and c(4) photosynthetic carbon metabolism

Exposure of maize leaves to a 3-hour photoinhibitory treatment (photon flux rate of 2,000 microeinsteins meter⁻² second⁻¹, CO₂-free air) resulted in lower activities of the light-activated enzymes NADP malate dehydrogenase, pyruvate, Pi dikinase, and ribulose-5-phosphate kinase. The activities could be recovered partially either by incubating enzyme extracts with dithiothreitol or by illuminating the treated leaf in air. Several enzymes which are not light-activated were not affected by the treatment. Ribulose-5-phosphate kinase activity was also reduced when bean plants grown in low light were subjected to a similar photoinhibitory treatment.     

Interferon Production and Host Resistance to Type II Avian (Marek''s) Leukosis Virus (JM Strain)

Interferon production in both susceptible S- and resistant K-line chickens infected with type II leukosis virus of JM strain and turkey herpesvirus was studied. The resistant line of chickens produced higher levels of interferon than did the susceptible with JM virus infection during the experimental period. When both susceptible S-and resistant K-line chicks were vaccinated with turkey herpesvirus, the interferon production was quantitatively similar in the two lines.     

Interferon Production and Host Resistance to Type II Avian (Marek's) Leukosis Virus (JM Strain)

Interferon production in both susceptible S- and resistant K-line chickens infected with type II leukosis virus of JM strain and turkey herpesvirus was studied. The resistant line of chickens produced higher levels of interferon than did the susceptible with JM virus infection during the experimental period. When both susceptible S-and resistant K-line chicks were vaccinated with turkey herpesvirus, the interferon production was quantitatively similar in the two lines.     

Effect of the Aedes fluviatilis saliva on the development of Plasmodium gallinaceum infection in Gallus (gallus) domesticus

Effect of Aedes fluviatilis saliva on the development of Plasmodium gallinaceum experimental infection in Gallus (gallus) domesticus was studied in distinct aspects. Chickens subcutaneously infected with sporozoites in the presence of the mosquito salivary gland homogenates (SGH) showed higher levels of parasitaemia when compared to those ones that received only the sporozoites. However, the parasitaemia levels were lower among chickens previously immunized by SGH or non-infected mosquito bites compared to the controls, which did not receive saliva. High levels of anti-saliva antibodies were observed in those immunized chickens. Moreover, 53 and 102 kDa saliva proteins were recognized by sera from immunized chickens. After the sporozoite challenge, the chickens also showed significant levels of anti-sporozoite antibodies. However, the ability to generate anti-sporozoites antibodies was not correlated to the saliva immunization. Our results suggest that mosquito saliva components enhance P. gallinaceum parasite development in naive chickens. However, the prior exposure of chickens to salivary components controls the parasitemia levels in infected individuals.     

Enzymic activities of carbohydrate,purine, and pyrimidine metabolism in the Anaeroplasmataceae (class Mollicutes)

Cell-free extracts of two strictly anaerobic mollicutes, Anaeroplasma intermedium 5LA and Asteroleplasma anaerobium 161^T, were tested for enzymic activities of intracellular carbohydrate metabolism. Asteroleplasma anaerobium was also tested for enzymes of purine and pyrimidine metabolism. Both organisms had enzymic activities associated with the nonoxidative portion of the pentose phosphate pathway, and with the Embden-Meyerhoff-Parnas pathway. The 6-phosphofructokinase (PFK) of Asteroleplasma anaerobium was ATP-dependent, whereas the PFK of Anaeroplasma intermedium was PP_i-dependent. The two anaerobic mollicutes also differed with respect to the enzymes that converted phosphoenolpyruvate (PEP) to pyruvate; Anaeroplasma intermedium had pyruvate kinase activity, but Asteroleplasma anaerobium had pyruvate, orthophosphate dikinase activity (PP_i-dependent). Both organisms had lactate dehydrogenase activity which was activated by fructose 1,6-bisphosphate (Fru-1,6-P ₂). Anaeroplasma intermedium had activity for PEP carboxykinase (activated by Fru-1,6-P ₂), but Asteroleplasma anaerobium did not. PEP carboxytransphosphorylase activity was not detected in either organism. Anaeroplasma intermedium had malate dehydrogenase and isocitrate dehydrogenase activities, but it had no activities for the three other tricarboxylic acid cycle enzymes examined; Asteroleplasma anaerobium had malate dehydrogenase activity only. Asteroleplasma anaerobium had enzymic activities for the interconversion of purine nucleobases, (deoxy)ribonucleosides, and (deoxy)ribomononucleotides, including PP_i-dependent nucleoside kinase, reported heretofore only in some other mollicutes. Asteroleplasma anaerobium could synthesize dTDP by the thymine salvage pathway if deoxyribose 1-phosphate was provided, and it had dUTPase, ATPase, and dCMP kinase activities. It lacked (deoxy)cytidine deaminase, dCMP deaminase, and deoxycytidine kinase activities.Abbreviations EMP Embden-Meyerhof-Parnas - ICDH isocitrate dehydrogenase - LDH lactate dehydrogenase - PEP phosphoenolpyruvate - PFK phosphofructokinase - PPDK pyruvate, orthophosphate dikinase - TCA cycle tricarboxylic acid cycle Note: Other abbreviations used are as per the instruction to authors, or the reference cited therein (Eur J Biochem 1:259), or Biochem J 120:449 (which supercedes a portion of the first reference)     

Occurrence and metabolic role of the pyruvate dehydrogenase complex in the lower termite Coptotermes formosanus (Shiraki)

The activities of the pyruvate dehydrogenase complex in extracts of the gutted body, head, foregut/midgut and hindgut (hindgut epithelium and microorganisms) tissues of the lower termite Coptotermes formosanus (Shiraki) were determined by measuring the [¹⁴C]-acetyl-CoA produced from [2-¹⁴C]-pyruvate and the ¹⁴CO₂ produced from [1-¹⁴C]-pyruvate. The activities of pyruvate dehydrogenase, l-lactate dehydrogenase, acetyl-CoA synthetase, malate dehydrogenase (decarboxylating), and acetate kinase in the termite tissues and the hindgut also were determined. The sum (7.1 nmol/termite/h) of the pyruvate dehydrogenase complex activities in the termite tissues other than the hindgut was five times higher than the activity in the hindgut. Significant amounts of l-lactate dehydrogenase activity were found in all of the tissues. All of the tissues other than the hindgut had significant amounts of acetyl-CoA synthetase activity. Malate dehydrogenase (decarboxylating) activity was about ten times higher in the hindgut extract than in the gutted body and head extracts and the activity in the foregut/midgut extract was very low. These results indicate that acetyl-CoA for the TCA cycle is produced effectively in the tissues of the termite itself, both from pyruvate by the pyruvate dehydrogenase complex and from acetate by acetyl-CoA synthetase.     

Pyruvate kinase and creatine phosphokinase during development of the chicken with muscular dystrophy

Pyruvate kinase and creatine phosphokinase activities in breast muscle extracts and in serum, and protein content of the muscle extracts were determined during the first eight weeks of development of control and dystrophic chickens. In the dystrophic chicken serum enzyme levels were significantly greater than, and muscle protein content and enzyme activities on a gram wet weight basis were significantly less than control values, by the second week after hatching and thereafter. For both muscle and serum the relative differences between control and dystrophic groups was greater for pyruvate kinase than crearine phosphokinase. On a specific activity basis only pyruvate kinase levels in dystrophic muscle were significantly less than control values in 2–8-week-old chickens.