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PubMed1977

Metabolic regulation and relationship of endogenous protein kinase activity and steroidogenesis in isolated adrenocortical carcinoma cells of the rat.

In the adrenocortical carcinoma cell, in contrast to normal isolated adrenal cells, 10 to 50 muunits of ACTH do not raise the level of adenosine cyclic 3':5'-monophosphate (cyclic AMP), protein kinase activity, and steroidogenesis. This indicates a lesion in the tumor adenylate cyclase system. Two-tenths to 10 mM cyclic AMP and guanosine cyclic 3':5'-monophosphate (cyclic GMP) which stimulate steroidogenesis in a normal cell, activate protein kinase activity in a concentration-response manner without any detectable rise in steroidogenesis in the adrenocortical carcinoma cell. Cycloheximide and actinomycin D do not inhibit the stimulation of the phosphorylation. These results suggest that the tumor cyclic nucleotide-dependent protein kinase activity is unrelated to steroidogenesis and is also not under the transcriptional or translational control steps. Curiously, muM concentrations of cyclic AMP, in contrast to cyclic GMP, stimulate protein kinase activity. In a normal cell, both cyclic AMP and cyclic GMP, in this concentration range, stimulate protein kinase without an increase in steroidogenesis. It is therefore proposed that, in contrast to the normal cell, there is an additional defect in cyclic GMP-dependent protein kinase.

Adenylyl Cyclases↗
PubMed1979

Adenylate kinase activity and glutathione concentration of cerebrospinal fluid in different neurological disorders.

Adenylate kinase activity and glutathione concentration were measured in cerebrospinal fluid (CSF) of 64 consecutive patients admitted for various neurological disorders. These two analyses were performed in addition to conventional examination of the CSF. Neurological symptoms most probably connected in some cases with no and in others with only subtle changes in the central nervous system were linked to no or only moderate activities of adenylate kinase together with no glutathione. 1 patient with meningioma had no adenylate kinase activity at all while 3 patients with malignant brain tumours showed clear activities similar to 3 patients with well established diagnoses of multiple sclerosis. On the contrary, glutathione was absent in CSF of the patients with brain tumours and multiple sclerosis. Various cerebrovascular diseases involving larger areas of the brain tissue resulted in clear adenylate kinase activities in CSF either alone as in 11 of the patients with cerebral infarction or in combination with the appearance of also glutathione as in the remaining 7 patients with cerebral infarction as well as in the 14 patients studied with hemorrhages of the brain.

Adenylate Kinase↗
PubMed1975

Effect of PGE1 and TSH on cAMP-dependent protein kinase activity in the thyroid.

PGE1, like TSH, can increase cAMP-dependent protein kinase activity in calf thyroid slices. The intracellular levels of cAMP produced by either of these agents alone appeared to correlate well with the degree of kinase activation. PG synthesis did not appear to be necessary for TSH action in this system, since indomethacin, and inhibitor of prostaglandin synthesis, did not alter either cAMP levels or kinase activity in slices incubated with TSH. Both the cAMP level and kinase activity rose when a submaximally effective dose of TSH was added to a maximal dose of PGE1. However, neither the cAMP levels nor the kinase activity produced by a maximal dose of TSH was affected by the addition of PGE1.

Animals↗
PubMed1975

The assay of pyruvate kinase activity in gastric mucosa.

Pyruvate kinase activity in gastric mucosal supernatant preparations shows large responses to exogenous effectors. At pH 7.5, fructose 1,6-diphosphate can cause large stimulations in activity. Alanine inhibits the reaction but this effect is partially reversed by fructose 1,6-diphosphate. In the absence of these compounds, 4.0-5.0 mM phosphoenolpyruvate (PEP) is required to generate maximal activity in the assay system used. Electrophoresis reveals an isoenzyme pattern containing only one form of pyruvate kinase, an M isoenzyme, in both fundic and antral mucosa. The pyruvate kinase of gastric mucosa thus resembles the M-type enzymes of leucocytes and liver. Measurements of activity at both 1.0 mM PEP and 4.0--5.0 mM PEP, with and without additions of fructose 1,6-diphosphate, are recommended for the reliable estimation of pyruvate kinase activity in this tissue.

Animals↗
PubMed1978

Effect of lin-benzoadenosine and lin-benzoadenosine 3':5'-monophosphate on cyclic AMP-dependent protein kinase activity in vitro.

We have shown that the fluorescent "stretched-out" analog of cyclic AMP, namely linear-benzo-cyclic AMP, maximally activates brain protein kinase and protein kinase from skeletal muscle. The corresponding linear-benzoadenosine inhibits kinase activity slightly less than does adenosine. Thus, the 2.4A-wider versions of cyclic AMP and of adenosine interact with protein kinase in a manner similar to that of the natural compounds.

Adenosine↗
PubMed1979

Induction of interferon in HeLa cells of a protein kinase activated by double-stranded RNA.

Treatment of HeLa cells with human fibroblast interferon results in increased levels of latent protein kinase activity that can be activated by double-stranded RNA (dsRNA). The protein kinase activity in extracts of interferon-treated cells is assayed by two methods: (a) inhibition of protein synthesis in rabbit reticulocyte lysates and (b) phosphorylation of two polypeptides of Mr 72000 (P1) and 38000 (the eIF-2 alpha subunit of initiation factor 2). When extracts of interferon-treated cells are fractionated by centrifugation at 150000 x g, the protein kinase activity is found in the pellet fraction. The kinase is maximally activated by 0.1 micrograms/ml poly(I) . poly(C). An increase in protein kinase activity is detected after 8 h of treatment with 100 units interferon/ml or after a 17-h treatment with 12.5 units/ml or greater interferon concentrations. Therefore, the kinase activity increases as a function of both time of treatment and interferon concentration. Addition of actinomycin D to cells during interferon treatment prevents this increase. The protein kinase activity decreases gradually over three days when interferon-treated cells are subsequently grown in the absence of interferon.

Animals↗
PubMed1977

Induction of deoxypyrimidine kinase activity in human embryonic lung cells infected with varicella-zoster virus.

Deoxypyrimidine kinase (deoxythymidine [TdR] kinase and deoxycytidine kinase) activity was induced in human embryonic lung cells after infection with varicella-zoster virus (VZ virus). Increased enzyme activity was also produced by using cell-associated virus as inoculum instead of cell-free virus. Anti-VZ virus serum inhibited both the appearance of cytopathic effect and the induction of enzyme activity. The induced TdR kinase activity was more thermostable than that induced by herpes simplex virus type 1. Also, the TdR kinase activity of VZ virus-infected cells was inhibited by dTTP less than in mock-infected cells and more than in herpes simplex virus type 1-infected cells.

Cell Line↗
PubMed1976

Correlation of protein kinase activation and testosterone production after stimulation of Leydig cells with luteinizing hormone.

The effect of different doses of luteinizing hormone on activation of protein kinases, cyclic AMP and testosterone production was studied in purified rat testis Leydig-cell preparations in the presence of 3-isobutyl-1-methylxanthine (a phosphodiesterase inhibitor). In addition, the nature of the protein kinases present in these cells and other tissues was investigated. The following results were obtained. 1. With all the amounts of luteinizing hormone used (0.1-1000 ng/ml), both activation of protein kinase and stimulation of testosterone production were demonstrated. With the lowest amount of luteinizing hormone (0.1 ng/ml), an 8.4+/-0.9% (S.E.M.,n=6) stimulation of protein kinase activation occurred, increasing to 100% with 1000 ng/ml, compared with 3.2+/-1.0%(S.E.M.,n=7) and 100% stimulation of testosterone production with 0.1 and 100 ng/ml respectively. 2. With amounts of luteinizing hormone up to 1 ng/ml (which gave half-maximal stimulation of testosterone production) no detectable increases in net cyclic AMP production were obtained. With higher amounts of luteinizing hormone, cyclic AMP production increased, but maximal production was not reached with 1000 ng/ml. 3. Two isoenzymic forms of protein kinase were present in Leydig cells and seminiferous tubules; type I was eluted with 0.075 M-and type II with 0.22-0.25 m-NaCl from DEAE-cellulose columns. 4. The protein kinase activity was not affected by the presence of erythrocytes in the Leydig-cell preparation, but varied depending on the type of histone used as substrate (histone F2b greater than mixed greater than histone F1).

Animals↗
PubMed1978

Multiple forms of cytosol and membrane-bound protein kinase activity in human erythrocytes.

Both cytosol and membranes of human erythrocytes display protein kinase activity towards exogenous protein substrates such as casein, phosvitin and histones. The histone kinase activity, unlike casein kinase, of both cytosol and membranes is increased by cyclic AMP. The protein kinase forms removed from the membranes with 0.7 M NaCl, phosphorylate only serine residues of both casein and histones through a mechanism cyclic AMP-independent. The protein kinase activity located in the cytosol (hemolysate) is due also to enzyme forms phosphorylating both serine and threonine residues of casein, in addition to forms phosphorylating only serine residues of casein and histones. Also the cytosol kinase forms, once partially purified by Sepharose 6B filtration, appear to be cyclic AMP-independent.

Caseins↗
PubMed1976

Protein kinase activity in rat testis interstitial tissue. Effect of luteinizing hormone and other factors.

Protein kinase activity was determined in subcellular fractions of rat testis interstitial tissue after incubation of the intact tissue with LH (luteinizing hormone) in vitro. Various factors that might have changed the activity of this enzyme during preparation of the fractions before assay were also investigated. The following results were obtained. 1. LH and 3-isobutyl-1-methylxanthine (a phosphodiesterase inhibitor) added together during incubation of the interstitial tissue caused a twofold increase in the protein kinase activity in the total tissue homogenate and subcellular fractions (12000g X 5 min pellet and 105000g X 60 min supernatant and pellet). 2. A decrease of approx. 40% in the total amount of protein kinase recovered in the soluble fraction (105000g supernatant) occurred in tissue incubated with LH and 3-isobutyl-1-methylxanthine when compared with the controls. No change in total activity was found in the other fractions. 3. LH and 3-isobutyl-1-methylxanthine caused an increase in cyclic AMP concentration in the soluble fraction (from 30 +/- 6 to 450 +/- 40 pmol/mg of protein, means +/- S.E.M., n = 4), but there was little or no increase in the particulate fractions [from 9 +/- 1 to 13 +/- 3 pmol/mg of protein (n = 3) and from 6 +/- 2 to 23 +/- 11 pmol/mg of protein (n = 3) in the 12000g and 105000g pellets respectively]. 4 Addition of 3-isobutyl-1-methylxanthine alone had little effect on protein kinase activity or cyclic AMP concentrations. 5. Little or no protein kinase activity could be demonstrated in subcellular particulate fractions unless Triton X-100 was added; the effect of this detergent was shown to be at least partly due to the inhibition of adenosine triphosphatase activity. 6. In the presence of Triton X-100 approx. 57% of the total protein kinase activity in the homogenate was found in the 105000g supernatant compared with 11% in the 105000g pellet and 32% in the 12000g pellet. 7. In contrast with adipose-tissue protein kinase [Corbin et al. (1973) J. Biol. Chem. 248, 1813-1821] the relative amounts of cyclic AMP-dependent and -dependent enzyme were not affected by dilution of the interstitial-tissue fractions. NaCl (0.5 M) decreased the estimated total amount of protein kinase activity.

Adenosine Triphosphatases↗
PubMed1979

Effect of endotoxin on hepatic pyruvate kinase activity in normal and diabetic dogs.

The influence of endotoxic administration (0.5 mg/kg) on hepatic pyruvate kinase activity in normal (nondiabetic) and diabetic dogs was investigated. Pyruvate kinase activity was not affected four hours after endotoxin injection in nondiabetic dogs. However, it was stimulated by 288% in dogs that were made diabetic prior to the administration of endotoxin. Since pyruvate kinase activity in diabetic dogs without endotoxin treatment was not affected, these findings suggest that the stimulatory effect of endotoxin on pyruvate kinase activity in diabetic dogs may be associated with insulin deficiency and/or high ambient blood glucose level.

Animals↗
PubMed1978

Effects of osmolality and oxygen availability on soluble cyclic AMP-dependent protein kinase activity of rat renal inner medulla.

The renal inner medulla is ordinarily exposed to osmolalities that are much higher and to O2 tensions that are lower than those in other tissues. The effects of media osmolality and O2 availability on basal and arginine vasopressin(AVP)-responsive soluble cyclic (c)AMP-dependent protein kinase activity were examined in slices of rat inner medulla. Increasing total media osmolality from 305 to 750 or 1,650 mosM by addition of urea plas NaCl to standard Krebs-Ringer bicarbonate buffer significantly reduced basal cAMP content and protein kinase activity ratios. This occurred in the presence or absence of O2. Incubation of slices in high osmolality buffer also blunted increases in inner medullary slice cAMP and protein kinase activity ratios induced by O2. These changes reflected predominantly an action of the urea rather than the NaCl content of high osmolality buffers. In contrast to effects on basal activity, high media osmolality significantly enhanced activation of inner medullary protein kinase by AVP. Conversely, increases in media O2 content suppressed AVP stimulation of enzyme activity. This inhibitory effect of O2 was best expressed at low osmolality. Naproxen and ibuprofen, inhibitors of prostaglandin biosynthesis, reduced basal kinase activity ratios and increased AVP responsiveness in the presence, but not in the absence, of O2. Exogenous prostaglandins (PG) modestly increased (PGE2 and PGE1) or did not change (PGF2alpha) cAMP and protein kinase activity ratios in O2-deprived inner medullary slices. Protein kinase activation by PGE2 was not observed in oxygenated inner medulla with high basal activity ratios. The stimulatory effects of PGE2 and PGE1 on protein kinase activity observed in O2-deprived slices were additive with those of submaximal or maximal AVP. PGE2, PGE1, and PGF2alpha all failed to suppress AVP activation of protein kinase. Thus, enhanced endogenous PGE production may contribute to the higher basal protein kinase activity ratios induced by O2. However, the results do not support a role for PGE2, PGE1, or PGF2alpha in O2-mediated inhibition of AVP responsiveness. The present data indicate that both solute content and O2 availability can alter the expression of AVP action on cAMP-dependent protein kinase activity in inner medulla. AVP activation of protein kinase is best expressed when osmolality is high and O2 availability is low, conditions that pertain in inner medulla during hydropenia.

Animals↗
PubMedDate not supplied

[Pyridoxal kinase activity in human tumor tissues].

Activity of pyridoxal kinase (per 1 g of tissue or per 1 mg of protein) varied in the range from 7 to 39 un or from 0.079 to 0.4 un in human malignant neoplasm tissues (adenocarcinoma of various localization, squamatous cell carcinoma of lungs, skin melanoma). The direction of alterations in the pyridoxal kinase activity differed in various tumors studied as compared with the respective controls (unimpaired tissues used for growing malignant cells).

Adenocarcinoma↗
PubMed1978

Effect of propranolol and nitroglycerin plus methoxamine on transmural creatine kinase activity after acute coronary occlusion.

Transmural creatine kinase activity was determined 5 hours after acute occlusion of the left anterior descending coronary artery in 27 open chest anesthetized dogs. In seven dogs, propranolol, 2 mg/kg, was given intravenously over a 10 minute period 10 minutes after occlusion. In 10 dogs, nitroglycerin, 300 microgram/min, was infused intravenously for 1 hour 10 minutes after occlusion. Methoxamine, 300 to 500 microgram, was administered to return blood pressure and heart rate to prenitroglycerin levels. In untreated dogs, there was a distinct transmural gradient of creatine kinase activity in the ischemic region from subepicardium to subendocardium: nonischemic subepicardium 1,187 +/- 50 international units (IU)/g versus ischemic subepicardium 1,054 +/- 46 IU/g and nonischemic subendocardium 1,170 +/- 53 IU/g versus ischemic subendocard;um 766 +/- 42 IU/g, respectively. Administration of propranolol did not affect the transmural creatine kinase gradient after 5 hours of occlusion. In contrast, nitroglycerin plus methoxamine significantly (P less than 0.05) decreased subendocardial creatine kinase depletion after 5 hours of occlusion (776 +/- 42 versus 978 +/- 47 IU/g). These findings demonstrate the unique capability of nitroglycerin plus methoxamine to protect the subendocardium during ischemic insult.

Acute Disease↗
PubMed1976

G1 specific increases in cyclic AMP levels and protein kinase activity in Chinese hamster ovary cells.

Chinese hamster ovary cells were synchronized by selective detachment of cells in mitosis. The adenosine 3':5'-cyclic monophosphate (cyclic AMP) intracellular concentrations and cyclic AMP-dependent protein kinase activities were measured as these cells traversed G1 phase and entered S phase. Protein kinase activity, assayed in the presence or absence of saturating exogenous cyclic AMP in the reaction mixture, was lowest in early G1 phase (2 h after mitosis), increased 2-fold (plus exogenous cyclic AMP in reaction mixture) or 3.5-fold (minus cyclic AMP in reaction mixture) to maximum values in mid to late G1 phase (4-5 h after mitosis), and then decreased as cells entered S phase. Intracellular cyclic AMP concentrations were minimal 1 h after mitosis, increased 5-fold to maximum levels at 4-6 after mitosis, and decreased as cells entered S phase. Similar to the fluctuations in intracellular cyclic AMP, the cyclic AMP-dependent protein kinase activity ratio increased more than 40% in late G1 or early S phase. Puromycin (either 10 mug/ml or 50 mug/ml) administered 1 h after mitosis inhibited cyclic AMP-dependent protein kinase activity up to 50% by 5 h after mitosis, while similar treatment (10 mug/ml) had no effect on the increase in cyclic AMP formation. These data demonstrate that: (1) total protein kinase activity changed during G1 phase and this increase was dependent on new protein synthesis; (2) the increased intracellular concentrations of cyclic AMP were not dependent on new protein synthesis; and (3) the activation of cyclic AMP-dependent protein kinase was temporally coordinated with increased intracellular concentration of cycli AMP as Chinese hamster ovary cells traversed G1 phase and entered S phase. These results suggest that cyclic AMP acts during G1 phase to regulate the activation of cyclic AMP-dependent protein kinase.

Cell Line↗
PubMed1976

Effects of adenosine and its derivatives on protein kinase activity of beef thyroid.

Effects of adenosine and some of its derivatives on beef protein kinase activity were investigated in vitro. Adenosine rapidly inhibited protein kinase activity in a dose-dependent manner. Significant inhibition occurred with 10 muM and half-maximal inhibition at 100 muM adenosine. Inhibition was almost complete with 5 mM adenosine. Inhibition was similar whether protein kinase activity was assayed with or without cyclic AMP. The inhibition by adenosine was reversed by increasing the concentration of ATP and Lineweaver-Burk analysis indicated that adenosine inhibition was competitive with ATP. Addition of adenosine deaminase to the incubation medium prevented the inhibition induced by adenosine. Intact 1 and N6 positions of adenosine were important for the inhibition since their modification was associated with loss of inhibition. Modification of the 8 position of adenosine decreased, but did not abolish, the inhibition. The 2 and 3 position of ribose did not seem to be critical since 2- and 3-deoxyadenosine produced inhibition similar to that of adenosine.

Adenosine↗
PubMed1978

Cell cycle and the concept of physiological age with special reference to pyruvate kinase activity in WI-38 cells.

WI-38 cells were synchronized by mitotic collection and periodically assayed for pyruvate kinase activity. The kinetics of the synchronous cohort were determined by continuous labelling index and by mitotic index. The experimental data were analysed by computer using a state vector model to yield the probability density functions for phase transit times and for cell physiological ages. Pyruvate kinase activity for these cells as a function of physiological age was then examined using the computer model. Considering DNA synthesis, pyruvate kinase activity and mitosis to be markers of physiological age, it was found that a model which assumes that a cohort of synchronized cells desynchronizes irreversibly and uniformly from one age marker to the next is incompatible with the experimental data. For example, the times over which cells entered the S phase were too widely distributed to be consistent with the mitotic index data. Also, for pyruvate kinase activity to be a function of physiological age alone, the cell ages were probably too dispersed to be compatible with the experimental enzyme data. Alternative models for cell physiological ageing are presented, which are compatible with the experimental data.

Cell Cycle↗
PubMedDate not supplied

[Adenylate kinase and creatine kinase activity of rabbit blood serum following application of a tourniquet to the thigh].

A colorimetric method is described for estimation of the adenilate kinase activity in blood serum; the method is based on coupling of adenilate- and creatine kinase reactions and on estimation of the amount of creatine formed. Adenilate kinase activity in blood serum, estimated by the method, was shown to increase 4-fold after removing of tourniquet with subsequent normalization within the next day. The same data were obtained using a spectrophotometric method for estimation of adenilate kinase based on NADP reduction in coupled reactions with hexokinase and glucose-6-phosphate dehydrogenase. An increase in creatine kinase activity in blood serum occurred later on after removing of the tourniquet; it was more distinct (8.5-fold) and maintained longer as compared with the increase in adenilate kinase activity.

Adenylate Kinase↗