[Activity of enzymes participating in xenobiotic metabolism and the condition of microsomal membranes of rat liver in vitamin K deficiency]

Alimentary deficiency or vitamin K (vitamin K-poor diet) as well as the vitamin deficiency resulting from sinkumar administration are accompanied by a decreased activity of microsomal demethylases, hydroxylase, NADH- and nNADPH-reductases of dichlorophenolindophenol and neotrazolium. The activity of cytosolic enzymes (only glutathione-S-transferases, aryl- and allyl esterases) is diminished in a lesser degree. Vitamin K deficiency does not significantly interfere with the effect of the xenobiotic metabolism enzyme inducer (phenobarbital) or the cytochrome P-450 inhibitor (cobalt chloride). The changes in the enzyme activity result in a decrease of acetanilide biotransformation. A possible reason for the observed changes in the activity of microsomal enzymes is the weakening of hydrophobic and polar interactions in microsomal membranes. This hypothesis was confirmed by experiments with the use of membrane perturbants as well as by solubilization of membrane-bound enzymes.

[Are the receptors of 1,25-dihydroxyvitamin D3 vitamin K dependent?]

Alimentary deficiency of vitamin K in rats causes a decrease in the level of in vivo occupied nuclear 1,25 (OH)2D3 receptors in small intestinal mucosa and an 2-2.5-fold increase in the ability of cytosolic 1,25 (OH)2D3-receptor complexes to bind to heterologous DNA. The 1,25 (OH)2D3 binding by the receptors is thereby unaffected. Preincubation of kidney and intestinal cytosol of rats with the secondary K-avitaminosis induced by vitamin K antagonist with the microsomal vitamin K-dependent gamma-carboxylation system sharply decreases the binding of the 1.25 (OH)2D3-receptor complexes to DNA. In rats treated with the vitamin K antagonist in combination with a low calcium diet, the subsequent maintenance on a high calcium diet does not cause, in contrast with vitamin K-repleted animals, a sharp decrease of the level of the in vivo occupied 1,25 (OH)2D3 receptors. In vitro Ca2+ cations decrease the binding of the 1,25 (OH)2D3-receptor complexes to DNA only in vitamin K-repleted rats (ED50 = 2.5 x 10(-6) M). The existence of a vitamin K-dependent Ca-sensitive mechanism regulating the binding of the 1,25 (OH)2D3 receptor to DNA has been postulated for the first time.

[Activity of various enzymes of energy metabolism in the rat kidney and intestines in vitamin D and K deficiency]

The vitamin D and K deficiency was studied for its effect on creatine kinase, phosphorylase and alkaline phosphatase activity of rat kidneys and intestinal mucosa. The results show that creatine kinase and phosphorylase activity of kidneys varies depending on the content of these vitamins, e.g. it is activated with vitamin D depletion irrespective of the vitamin K status and remains unchanged with the deficiency of vitamin K alone. In this case the vitamin D deficiency affects kidney phosphorylase and intestinal mucosa differently. Data obtained and those available in literature permit suggesting that the deficiency of the same vitamin may exert a different action on the activity of isoforms of such enzymes as creatine kinase and phosphorylase.

Studies on oxacephem antibiotics: comparison of the effects of 1-oxa and 1-thia cephalosporins on blood coagulation activities and vitamin K metabolism in rats

Oxacephem antibiotics have been developed to increase the antibacterial activity of cephem antibiotics, but the effect of 1-oxygen replacement of cephem antibiotics on blood coagulation activities is not yet known. Therefore, latamoxef (LMOX), flomoxef (FMOX) and their 1-S congeners were examined for their effects on prothrombin time, activated partial thromboplastin time, plasma prothrombin and Factor VII levels, plasma and liver descarboxyprothrombin (PIVKA-II) levels, and liver microsomal vitamin K epoxide reductase activities in rats kept on a vitamin K-deficient diet. Under the vitamin-deficient states, LMOX, FMOX and their 1-S congeners inhibited the vitamin K epoxide reductase, although the effect of FMOX or its congener was much less than that of LMOX, and they decreased the blood clotting activities in rats fed a vitamin K-deficient diet. However, no difference was found in these effects between LMOX and its 1-S congener or between FMOX and its 1-S congener. This result suggests that the 1-oxygen replacement of cephem antibiotics is not responsible for the hypoprothrombinemic effect of the antibiotics.

Effect of various intakes of phylloquinone on signs of vitamin K deficiency and serum and liver phylloquinone concentrations in the rat

The relationship between dietary phylloquinone, serum and liver concentrations of phylloquinone, and various indices of vitamin K adequacy have been studied in male rats fed a purified diet containing various levels of phylloquinone. In excess of 500 micrograms phylloquinone/kg diet was needed to prevent the most sensitive signs of vitamin K deficiency. Liver phylloquinone concentrations were shown to be correlated with dietary phylloquinone intake. Serum phylloquinone was not correlated with either diet or liver concentration of phylloquinone and did not increase with increased dietary intake until the liver contained sufficient vitamin to maintain optimal synthesis of vitamin K-dependent proteins. Because of the rapid loss of vitamin from the liver, prior ingestion of a high level of vitamin K had little influence on liver vitamin K concentrations beyond the first 2 d of a deficient period. When rats consumed a diet containing 500 micrograms phylloquinone/kg diet in 3 h, liver and serum phylloquinone concentrations fluctuated drastically following this feeding period. During the subsequent 24-h period, liver phylloquinone concentrations decreased to a level that would not support maximal activity of the hepatic vitamin K-dependent carboxylase.

[Calcium metabolism in the case of vitamin D and K deficiencies]

Moderate vitamin K deficiency was induced in growing rats by 4-week food ration deficient in vitamin K. It was characterized by prolongation of prothrombin time by 35%, and reduced by 23% in vitro calcium absorption by the duodenal disks in the animals provided with vitamin K, producing no significant effect on calcium concentration in the blood serum of rats with varying vitamin providing. Vitamin K deficiency did not influence the concentration of parathormone and 25-hydroxyvitamin D in the blood serum of rats provided with vitamin D, but it did not raise the degree of hyperparathemia in vitamin D deficiency and prevented the normalization of parathormone level after administration of physiological doses of vitamin D to rats deprived of this vitamin.

Vitamin K-dependent coagulation parameters during the first six days of life: incidence of PIVKA II in newborns

The vitamin K-dependent carboxylation of the prothrombin precursor PIVKA II (protein induced by vitamin K absence analogous to Factor II) is essential for the synthesis of prothrombin. The noncarboxylated precursor is found in peripheral blood in the presence of vitamin K deficiency. In this study prothrombin time, Factor II and Factor VII activity, and PIVKA II were investigated in 57 newborns without vitamin K prophylaxis in order to assess their vitamin K status. Two-dimensional immunoelectrophoresis demonstrated the presence of PIVKA II in 21% of the newborns, predominantly on the second day. The PIVKA-II positive group showed significantly lower prothrombin times than the PIVKA II-negative group. An oral dose of 3 mg vitamin K (Konakion) was administered to 35 healthy newborns in a second group with the first feeding. On the second day of life, these infants showed significantly higher vitamin K-dependent laboratory parameters than the group not given vitamin K; only 9% of the treated infants were positive for PIVKA II.

[The role of vitamin K in the interaction of 1,25-dihydroxyvitamin D3 receptors with DNA]

Vitamin K deficiency in rats caused a rise of in vivo occupied 1,25(OH)2D3 receptor level in chromatin of the intestinal mucosa and a marked (2-2.5-fold) increase of intestinal cytosolic 1,25(OH)2D3-receptor complex binding with heterologous DNA, whereas maximum binding capacity and equilibrium dissociation constant of cytosolic 1,25 (OH)2D3 receptors did not change. Preincubation of renal and intestinal cytosol of vitamin K-deficient rats with microsomal vitamin K-dependent gamma-carboxylating system reduced sharply 1,25(OH)2D3-receptor complex binding with DNA. In rats treated by vitamin K antagonist along with a low calcium diet, no dramatic decrease of occupied 1,25(OH)2D3 receptors occurred after the animals were maintained with a high calcium diet. No such effect was observed in vitamin K-replete rats. The data demonstrate vitamin K-dependent Ca-sensitive qualitative modification of 1,25(OH)2D3 receptor dropping its binding performance to DNA.

Warfarin administration reduces synthesis of sulfatides and other sphingolipids in mouse brain

The modulation of phosphosphingolipid synthesis by vitamin K depletion has been observed in the vitamin K-dependent microorganism, Bacteriodes levii. When cultured briefly without the vitamin, a reduction occurred in the activity of the first enzyme of the sphingolipid pathway, 3-ketodihydrosphingosine synthase. In this report, 16-day-old mice were treated with the vitamin K antagonist, warfarin. Brain microsomes from these animals showed a 19% reduction in synthase activity. Mice treated with warfarin for 2 weeks showed a major reduction in sulfatide level (42%), with a lesser degree or no reduction in levels of gangliosides and cerebrosides. In further experiments, mice were treated with warfarin for 2 weeks and a group was then injected with vitamin K1 (aquamephyton) for 3 days. Enzyme activity returned to a normal level within 2-3 days. Sulfatide levels had increased 33% in the vitamin K-injected group and ganglioside levels also increased, where levels of cerebrosides and sphingomyelin declined. Sulfatide synthesis determined by [35S] sulfate incorporation, showed a 52% increase in incorporation following administration of vitamin K for 3 days. These results suggest a role for vitamin K in the biosynthesis of sulfatides and other sphingolipids in brain. This putative role could be by post-translational protein modification analogous to the role of vitamin K in other systems.

[The effect of vitamin K deficiency in rats on various enzyme systems participating in energy metabolism]

In alimentary deficiency of vitamin K in rats, accompanied by an increase in the prothrombin time by 30%, activity of kidney creatine kinase and of blood serum alkaline phosphatase was unaltered, while the activity of alkaline phosphatase in small intestinal mucose was decreased by 20% and that of creatine kinase from skeletal muscles--by 10%. In vitamin K-deprived animals the rate of coupling between respiration and mitochondrial phosphorylation was decreased, which might be due to alteration in the NADH-dehydrogenase complex. Menadion reductase activity and cyanide-resistant respiration of mitochondria were unaltered in presence of menadion. Palmitic acid effectively activated of mitochondrial respiration in vitamin K-deprived animals (contrary to the control rats). This effect appears to occur as a result of structural alterations in mitochondria depending on vitamin K level in the organelles.

[The effect of vitamin K on the activity of glycolysis and pentose phosphate cycle enzymes]

Effect of naphthoquinone levels on the activity of enzymes involved in glycolysis and pentose phosphate cycles was studied in male rats. Under conditions of primary and secondary K-avitaminosis the enzymatic activity, limiting these cycles, (aldolase of fructose-1,6-diphosphate, glucose phosphate isomerase and glucose-6-phosphate dehydrogenase) was increased, while the mitochondrial glutamate dehydrogenase activity was decreased. As a result of metabolic transformations under conditions of K-avitaminosis (primary and secondary) concentration of DNA in the animal tissues was lowered.

Vitamin K1 content of maternal milk: influence of the stage of lactation, lipid composition, and vitamin K1 supplements given to the mother

Using a sensitive electrochemical assay for vitamin K1 and standardized techniques for breast-milk collection, we studied the vitamin K1 content of human milk during the first 5 wk of lactation with respect to 1) individual and interindividual differences, 2) the relationship of vitamin K1 to other lipids, and 3) the influence of oral supplements of vitamin K1 on breast milk concentrations. Comparison of fore and hind milk from the mothers revealed higher vitamin K1 concentrations in hindmilks, suggesting that the lipid content influences the vitamin K1 concentration in maternal milk. Samples of maternal milk from nine mothers collected from day 1 to day 36 of lactation showed significantly higher vitamin K1 concentrations in colostral milk than in mature milk. For colostral milk there was a significant correlation of vitamin K1 to cholesterol (r = 0.62) but not to total lipid or phospholipid suggesting a role for cholesterol in the secretion of vitamin K1 into colostral milk. For mature milk correlation coefficients of vitamin K1 with all lipids were low (r = 0.29-0.37) suggesting that at later stages of lactation dietary fluctuations of vitamin K1 may be a more important determinant of the vitamin K1 content of breast milk than the lipid composition. To test the influence of diet, mothers were given oral supplements of vitamin K1.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of a vitamin K-deficient diet and antibiotics in normal human volunteers

Decreased concentrations of vitamin K-dependent plasma clotting factors are a well-documented response of vitamin K-deprived patients administered broad-spectrum antibiotics. It has recently been claimed that antibiotics containing a N-methylthiotetrazole (NMTT) side chain cause this response through a direct effect of NMTT on the vitamin K-dependent posttranslational carboxylation of these clotting factors. To further study these relationships, 11 groups of three volunteers were fed a synthetic vitamin K-free diet for 2 weeks. During the last 10 days of vitamin K restriction, seven of the volunteer groups received a therapeutic dose of antibiotics not containing NMTT: ampicillin, sulfamethoxazole-trimethoprim (Bactrim), cefoxitin, cefotaxime, ceftazidime, clindamycin, and piperacillin, and three groups received NMTT-containing antibiotics: moxalactam, cefamandole, and cefoperazone. Serum phylloquinone (vitamin K1) concentrations reflected dietary intake and fell from 1.4 +/- 0.9 ng/ml after 3 days of hospital diet to 0.4 +/- 0.3 ng/ml after 13 days of vitamin K-free diet. Median stool excretion of phylloquinone was 19 micrograms/day while subjects consumed the hospital diet, and fell to 3 micrograms/day by day 6 on vitamin K-free diet. Prothrombin times remained within the normal range throughout the study. Suppression of vitamin K-dependent clotting factor biosynthesis was evident by decreased factor VII levels in seven of the volunteers and by an increased concentration of des-gamma-carboxy (abnormal) prothrombin in 21 of the volunteers. The changes occurred in the control subjects and in subjects receiving all nine of the 10 antibiotics with no consistent pattern.(ABSTRACT TRUNCATED AT 250 WORDS)

Evidence for a warfarin-sensitive serum factor that participates in factor X activation by Lewis lung tumor cells

Mouse Lewis lung (LL) carcinoma cells possess a factor X activator (procoagulant) that is inhibited in vivo by warfarin treatment or diet-induced vitamin K deficiency. This inhibition suggests that vitamin-K-dependent proteins are involved in LL cell activation of factor X. A LL primary tumor clone (LL13) was isolated which contained a warfarin-sensitive vitamin-K cycle of metabolism and expressed factor X procoagulant activity. LL13 cells exposed to media containing warfarin or deficient in vitamin K grew as well as cells in normal media, and activated factor X to similar extents. In contrast, administration of warfarin to mice bearing LL13 cells inhibited factor X procoagulant activity as well as the vitamin K cycle of metabolism in the primary tumors. In relation to LL13 cells grown in media containing fetal bovine serum, those incubated for 20 hr in media containing mouse serum or the sera from LL13-bearing mice exhibited 9- to 10-times higher levels of factor X procoagulant activity. However, LL13 cells exposed to media containing the sera of warfarin-treated LL-13-bearing mice or to barium-sulfate-adsorbed normal mouse serum activated factor X much less efficiently. Collectively, these data suggest that inhibition of vitamin K function in LL cells does not affect the extent of factor X activation and thus the intrinsic factor X procoagulant is not a vitamin-K-dependent protein. They further suggest that both a warfarin-sensitive (vitamin-K-dependent) protein present in normal mouse serum and a LL13 cell component participate in factor X procoagulant activity.

Screening for late neonatal vitamin K deficiency by acarboxyprothrombin in dried blood spots

Acarboxyprothrombin (protein induced by vitamin K absence or antagonist-II (PIVKA-II] concentrations in dried blood spots were determined in 19,029 infants at about 1 month of age as an indicator of vitamin K deficiency. We observed 51 cases with raised blood concentrations of PIVKA-II (greater than 4 AU/ml), nine of whom showed very high concentrations (greater than 20 AU/ml). For infants who did not receive vitamin K prophylaxis at birth, the incidence of the PIVKA-II test yielding positive results was significantly higher in those solely breast fed (0.51%) compared with those fed formula milk (0.18%). Among solely breast fed infants, the incidence of a very high result of the PIVKA-II test was 0.14% in those who had not received vitamin K prophylaxis at birth, 0.04% in those who received 2 mg orally, and 0.03% in those who received 2 mg orally plus a further dose of 2-4 mg orally at 7 days. Thus vitamin K prophylaxis at birth did not completely prevent vitamin K deficiency at 1 month. We administered vitamin K therapeutically to all infants whose PIVKA-II test yielded a positive result at 1 month. Only one infant with a positive result developed late neonatal intracranial haemorrhage.

[Effect of different supplies of vitamin K on the biotransformation of amidopyrine and benzoic acid in the rat]

Group I rats were given orally syncumar (1.5 mg/kg/day) during 5 days to induce K-avitaminosis. Group II and III animals received vikasol, a synthetic analogue of vitamin K (3 and 30 mg/kg/day, respectively), during 6 days. Delayed biotransformation of amidopyrine was recorded in the animals with vitamin K deficiency. The total 4-aminoantipyrine excretion was reduced due to a steady decrease in the excretion of both free form of this substance and its acetylated metabolite. Delayed conversion of benzoic acid into hippuric acid and benzoyl glucuronides was noted in rats with K-avitaminosis. Vikasol administration stimulated biotransformation of amidopyrine and benzoic acid, the low doses of vikasol (3 mg/kg) being more effective as compared to the high doses (30 mg/kg).

Effect of latamoxef on platelet function and prothrombin time in partially nephrectomized rats

Latamoxef (daily 100 and 300 mg/kg, i.v.) was injected once a day for 8 days to 75% and 90% nephrectomized rats kept on a vitamin K-sufficient diet (500-600 ng/g) or a vitamin K-deficient diet (30-50 ng/g), and changes in ADP-induced platelet aggregation and prothrombin time were examined. The half-life of latamoxef was markedly prolonged and plasma latamoxef and N-methyltetrazolethiol (NMTT) concentrations increased, resulting in a delay of the total body clearance of the compounds. The ADP-induced platelet aggregation increased after nephrectomy, and latamoxef slightly but inconsistently decreased the aggregation. Prothrombin time did not change even in the 90% nephrectomized rats kept on an ordinary diet, but increased dose-dependently in the vitamin K-deficient nephrectomized rats, with the 90% nephrectomized animals showing larger increases of prothrombin time. These data suggest that NMTT or NMTT-containing antibiotics cause no hypoprothrombinemia even in partially nephrectomized rats when they are fed an ordinary diet containing vitamin K, but these compounds enhance the manifestation of hypoprothrombinemia in vitamin K deficiency. Further renal failure promotes the manifestation by increasing drug concentration in the blood. However, platelet aggregation in these animals is not significantly affected at the doses examined.

[The role of N-quinones in the regulation of glucose-6-phosphate metabolism]

In experimental (white rats, rabbits) and clinical (erythrocytes, blood plasma) studies on 29 healthy subjects and patients it has been demonstrated that primary or secondary n-quinone deficiency is accompanied by increased tissue activity of glycolysis enzymes (aldolase, PGmutase) and aerobic pentose phosphate shunt (6 GPDH). Parallel rise in the amount of glycolysis metabolites (pyruvate and lactate) in the blood and the decline in blood plasma glucose level were observed. The changes in glucose-6-phosphate metabolism are, probably, secondary and reflect tissue structure alterations in the development of K and E avitaminosis.

[Effect of naphthoquinones and tocopherols on the level of integral proteins in mitochondrial membranes and DNA levels in rat and rabbit tissue]

Naphthoquinones and tocopherols are studied for their effect on the state of integral proteins of the mitochondrial liver and myocardium membranes in the experiments on the male rats and rabbits. It is established that deficiency of vitamins K and E in the organism (naphthoquinones and tocopherols) is followed by a decrease in the content of integral proteins and by disturbances in correlation of their fractions. These changes in K, E-avitaminosis are accompanied by a decrease of the DNA content in the tissues. Realization of K and E vitamins on the level of structural biomembrane organization is supposed to be possible.

Liver and plasma levels of descarboxyprothrombin (PIVKA II) in vitamin K deficiency in rats

Descarboxyprothrombin (PIVKA II) is a precursor of prothrombin without biological activity, and it increases with vitamin K deficiency. We studied the time course changes in liver and plasma levels of PIVKA II during the progress of vitamin K deficiency in rats. Good correlation was observed between liver PIVKA II and plasma PIVKA II and between liver or plasma PIVKA II and plasma prothrombin in experiments in which rats were fed a vitamin K-deficient diet. Feeding of a vitamin K-deficient diet or fasting caused marked increases in liver and plasma PIVKA II in male rats and a weaker response in female rats. Warfarin, a vitamin K antagonist, caused an abrupt increase in liver PIVKA II, but the increase in plasma PIVKA II was delayed about 3 hr. Plasma prothrombin decreased from about 30 min later. Factor VII decreased similarly to prothrombin, and changes in the prothrombin time and activated partial thromboplastin time were slower than the changes in these substances. Sex differences were not seen in these warfarin actions. These observations indicate that liver and plasma PIVKA II are sensitive markers of vitamin K deficiency in rats, and assay of PIVKA II can be useful for analyzing the action mechanism of drugs which influence blood coagulation.

The stereochemistry of hydrogen abstraction in vitamin K-dependent carboxylation

The stereochemistry of the hydrogen abstraction in the vitamin K-dependent carboxylation of synthetic peptides has been investigated; the carboxylation rates of various peptidic substrates containing a stereospecifically 4-monodeuterated glutamic acid residue have been compared to that of nondeuterated peptides. A significant isotope effect was found only with the substrates containing (4S)-4-deuterated glutamic acid. These data reveal that the rat liver microsomal vitamin K-dependent carboxylase acts stereospecifically in abstracting the 4-pro-S hydrogen of the glutamyl residue. The low values of the measured isotope effects indicate that the hydrogen abstraction does not constitute a limiting step in the carboxylation mechanism.

Vitamin K-dependent carboxylation: inhibition by a peptide containing 4-methylene glutamic acid

The peptide Boc-4-methylene Glu-Glu-Val has been synthesized and shown to be a strong inhibitor of the vitamin K-dependent carboxylation catalyzed by a detergent solubilized rat liver microsome preparation. The inhibition is apparently competitive with respect to the substrate peptide and non-competitive with respect to HCO3-.

Formation of 3-hydroxy-2,3-dihydrovitamin K1 in vivo: relationship to vitamin K epoxide reductase and warfarin resistance

Hydroxy vitamin K [3(2)-hydroxy-2,3- dihydrovitamin K1] has been identified as a quantitatively important metabolite of injected vitamin K epoxide in vivo. The metabolite has been isolated and identified by comparison of its UV, mass spectra and high-performance liquid chromatography (HPLC) retention times with those of synthetic standards, and by its characteristic conversion to vitamin K quinone on treatment with the base triethylamine. This metabolite is formed from the vitamin K epoxide, not from the vitamin K quinone and can represent up to 3.5% of dose and 13% of hexane-extractable metabolites present in liver 1 hour after injection of 330 micrograms vitamin K1 epoxide per kilogram body weight. It is formed in both normal and warfarin-resistant rat strains, but to a significantly greater extent in the latter. Unlike the hydroxy vitamin K formed by warfarin-resistant rat liver microsomes in vitro, the metabolite formed from racemic vitamin K epoxide in vivo was not optically active, nor was its formation inhibited by coumarin anticoagulants under conditions that completely blocked vitamin K epoxide reduction in vivo. On this basis, hydroxy vitamin K formation in vivo differs from its formation in vitro; it is not a product of vitamin K epoxide reductase in vivo, but of some other possibly non-enzymatic reaction.