VITAMIN B12, THIAMINE,AND BIOTIN CONTENTS OF MARINE PHYTOPLANKTON1

An extraction procedure was developed for determining vitamin B₁₂, thiamine, and biotin contents of marine phytoplankton. Phytoplankters were collected either by centrifugation or by retention on a glass fiber filter, then heated at 100 C for I hr in 100 ml of vitamin-free seawater acidified to pH 3.5 with HCl. The extract, after debris removal, was filter-sterilized and analyzed, for vitamin B₁₂, thiamine, and biotin with standard vitamin assay procedures. The vitamin contents of haeodactylum tricornutum, Skeletonema costatum, Stephanopyxis turris, and occolithus liuxleyi were determined during growth in batch cultures. P. tricornutum (non-vitamin requirer) growing in aerated cultures contained 0.29–0.96 ng B₁₂, 5–15 ng thiamine, and 0.45–1.70 ng biotin/mg C. Under similar conditions S. costatum (B₁₂-requirer) contained about 0.06 ng B₁₂, 5–36 ng thiamine, and 0.16–2.10 ng biotin/mg C. The concentrations of vitamin were generally similar during some portion of the growth curve, eg, logarithmic growth. The vitamin B₁₂, content of S. costatum growing under nonaerated conditions decreased when medium B₁₂, was reduced. The biotin content did not change when medium B₁₂ was decreased. The thiamine content per unit weight of C. huxleyi (thiamine-requirer) growing with either 10 or 120 ng/liter thiamine decreased under both medium concentrations, indicating no net synthesis of the vitamin.     

PRODUCTION OF VITAMIN B12, THIAMINE,AND BIOTIN BY PHYTOPLANKTON1

Some ecologically important phytoplankters released vitamins into culture medium during growth. Skeletonema costatum and Stephanopyxis turris (vitamin B₁₂-requirers) produced both thiamine (vitamin B₁) and biotin when growing with either 12 or 2 ng vitamin B₁₂/liter. Gonyaulax polyedra (vitamin B₁₂-requirer) produced thiamine with 12 ng vitamin B₁₂/liter, and Coccolithus huxleyi (thiamine-requirer) produced vitamin B₁₂ and biotin with 120 ng thiamine/liter, but only biotin with 10 ng thiamine/liter. The amount of vitamin produced by an alga and rate at which it was produced varied with the phytoplankter, the concentration of the required vitamin, and incubation time. Vitamins produced during early and exponential growth were due to excretions, and those produced at stationary growth resulted from excretion and release due to cell lysis. Uptake of the required vitamin by all phytoplankters was greatest during the first few days of incubation. On continued incubation the rate of uptake/cell decreased. In the sea phytoplankters may contribute a major portion of the amount of dissolved vitamins.     

Effect of water soluble vitamins and their analogues on growth of Candida albicans II. Vitamin B12, thiamine,oxythiamine, neopyrithiamine,substituted pyrimidines and thiazoles

Summary By employing wide ranges in vitamin concentrations in biotin basal mineral synthetic medium, it was demonstrated that vitamin B₁₂ markedly stimulated the growth ofCandida albicans, the organism showing a partial dependency upon this vitamin. Growth inhibition by 5-fluorouracil was reversed non-competitively by vitamin B₁₂, suggesting that B₁₂ has a role in nucleic acid biosynthesis of the organism. Thiamine was growth stimulatory, the organism being partially dependent upon this vitamin as well. Neopyrithiamine and oxythiamine were growth inhibitory in thiamine-free biotin basal mineral synthetic medium although the halves of each inhibitor compound were non-inhibitory. Neopyrithiamine inhibition was reversed by intact thiamine but not by pyrimidine thiamine or thiazole thiamine; while oxythiamine inhibition was reversed by thiamine and pyrimidine thiamine but not by thiazole thiamine, the inference being drawn that oxythiamine selectively blocks utilization of pyrimidine thiamine. Twenty-seven different substituted pyrimidines, thiazoles and related thiamine compounds were all utilizable byC. albicans in thiamine-free basal synthetic mineral medium, the organism presumably synthesizing thiamine when presented with the constituent parts of these thiamine analogues. Substitution of sulfur of the thiazole ring with oxygen, as in -methyloxazolium, failed to produce an inhibitory compound forC. albicans. Acetylthiamine, allithiamine, cocarboxylase, tetrahydrothiamine and dihydrothiamine were equally as growth stimulatory as thiamine.     

EFFECT OF VITAMIN CONCENTRATIONS ON GROWTH AND DEVELOPMENT OF VITAMIN-REQUIRING ALGAE1

Vitamin-requiring marine algae, Cyclotella nana, Monochrysis lutheri, and Amphidinium carterae, were grown in batch culture with limiting concentrations of vitamin B₁₂, thiamine, and biotin, respectively. Cell numbers, average cell volumes, biomasses, ¹¹CO₂ uptake rates, and chlorophyll a contents were determined daily. Maximum ¹⁴CO₂ uptake rates in most vitamin concentrations were obtained at 2 days with C. nana and M. lutheri and at 4 days with A. carterae after starved cultures were exposed to the vitamin. Radiocarbon uptake rates approximately reflect biomass increases. Cell numbers were proportional to vitamin concentrations when cells were incubated for 2 to 3 more days. Cell sizes varied depending on time of incubation. Chlorophyll a content did not always reflect vitamin concentrations. Maximum carbon assimilation rates (K_m) and saturation constants (K_s) determined from ¹⁴CO₂, uptake rates in different vitamin concentrations during early incubation were higher than when determined from cell number in log phase growth. Dissolved vitamin B₁₂, thiamine, and biotin in many samples of seawaters were in the ranges which influence the growth rate, cell size, and chlorophyll a content of C. nana, M. lutheri, and A. carterae, respectively, in laboratory studies. The effects of vitamins on these algae in situ may be similar.     

VITAMIN PRODUCTION AND UTILIZATION BY PHYTOPLANKTON IN MIXED CULTURE1

The production and utilization of vitamins by 2 or more, marine phytoplankters cultured in the same vessel were demonstrated. The release of toxic materials or vitamin inactivators wax also observed. The utilization of vitamins by those phytoplankters requiring them and the production of toxic materials were determined from increases and decreases in cell numbers of certain algae grown in mixed cultures. Vitamin utilization was most readily observed in mixed cultures where 2 phytoplankters were present. Dunaliella tertiolecta and Skeletonema costatum produced utilizable thiamine for Coccolithus huxleyi. C. huxleyi released utilizable vitamin B₁₂ for Cyclotella nana. D. tertiolecta, Phaeodactylum tricornutum, and S. costatum produced utilizable biotin for Amphidinium carterae. The amount of utilizable vitamin and rate at which it was released depended on the phytoplankters present and conditions of incubation. In complex systems with more than 2 phytoplankters, beneficial effects to utilizers were often noted for short durations during the incubation period. At the end of the experiments the beneficial effects were usually not evident. P. tricornutum (nonvitamin requirer) was stimulated by a mixture of carryover B₁₂ and thiamine when growing with A. carterae, indicating that in vitamin-free media it cannot synthesize vitamin(s) fast enough to allow for a maximum growth rate. The concentrations of vitamins in seawater samples may not be the amounts available to vitamin-requiring organisms. Among the factors affecting vitamin availability are the production of inhibitors and vitamin inactivators by various organisms in the ecosystem.     

GROWTH OF VITAMIN B12-LIMITED CULTURES: THALASSIOSIRA PSEUDONANA,MONOCHRYSIS LUTHERI,AND ISOCHRYSIS GALBANA1,2

The growth rates of 3 species of phytoplankton were found to be dependent on the vitamin B₁₂ concentrations in the media. In batch cultures, the vitamin B₁₂ half-saturation constants and standard errors were 0.39 ± 0.042 μμg/ml for Thalassiosira pseudonana (clone 3H), 1.69 ± 0.24 μμg/ml for Isochrysis galbana, and 2.77 ± 1.65 μμg/ml for Monochrysis lutheri. A chemostat was used to grow T. pseudonana with vitamin B₁₂ as the controlling factor. In the chemostat the yield and standard deviation, 102 ± 21 × 10⁴ cells/μμg vitamin B₁₂, was the same as in the batch culture, 126 ± 13 ± 10⁴ cells/μμg. The chemostat half-saturation constant, 0.26 ± 0.068 μμg/ml vitamin B₁₂, and maximum growth rate were in agreement with those obtained in batch cultures. Vitamin concentrations for maximum growth, rates were greater than those calculated necessary from yield data to give observed population densities similar to those in natural waters. In the sea the effect of vitamin B₁₂ concentration on growth rates may be complicated by low concentrations of other nutrients or the presence of inhibitors.     

Seasonal Cycles of Vitamin B12, Thiamine and Biotin in Lake Sagami. Patterns of Their Distribution and Ecological Significance

Seasonal cycles of vitamin B₁₂, thiamine and biotin in the water and sediment of Lake Sagami have been studied for two years in 1970 and 1971 at monthly intervals. They were compared with other biological and chemical factors. Sediments were very rich in the three vitamins during the period of study and they were considered to be a vitamin source for the Jake water. In the surface water, fluctuations both of dissolved and particulate forms of the vitamins were found to correspond fairly with the succession of phytoplankton during these years. Particularly, the dissolved vitamin B¹² concentration decreased remarkably at the same time that the particulate form increased considerably in the surface water during periods of dominance by diatoms such as Cyclotella sp., Nitzschia acicularis, N. paleacea, N. actinastroides, N. palea, N. sp. and Synedra acus. From the results, the possible importance of vitamin B₁₂ as one of the ecological factors in Lake Sagami was suggested and discussed.     

ASSESSMENT OF INTAKE AND NUTRITIONAL STATUS OF VITAMIN B1, B2, AND B6 IN MEN AND WOMEN WITH DIFFERENT PHYSICAL ACTIVITY LEVELS

The purpose of the present study was to examine the nutritional status of vitamin B₁, B₂, and B₆ in respect to dietary intake of these vitamins and activity coefficients of the erythrocyte enzymes transketolase, glutathione reductase, and aspartic aminotransferase in young men and women with different physical activity levels. The participants of this study were 20 women and 20 men with high physical activity (groups HAW and HAM, respectively), and 20 women and 20 men with low physical activity (groups LAW and LAM, respectively). The intake of vitamins B₁, B₂, B₆, proteins, and calorie content of the diet was based on the average of the 4-day dietary recalls. To assess nutritional status of vitamin B₁, B₂, and B₆, the activity coefficients (α) of erythrocyte transketolase (ETK), erythrocyte glutathione reductase (EGR), and erythrocyte aspartic aminotransferase (EAST) were estimated in blood hemolysates. The intake of the studied vitamins in the diet was statistically significantly lower in the female groups compared with the respective male groups. Deficiency of vitamin B₆ in the diet was present more often in women than in men (in terms of the recommended dietary allowances [RDA]). Values of the activity coefficient α_ETK indicated that none of the groups in this study suffered the risk of vitamin B₁ deficiency. The value of the activity coefficient α_EGR indicated that the groups of women and men with low physical activity were more prone to vitamin B₂ deficiency compared with the high physical activity groups. The risk of vitamin B₆ deficiency (α_EAST) in both male groups was higher than in both female groups. The obtained results do not allow for unequivocal determination of the impact of sex and the level of physical activity on intake and nutritional status of vitamin B₁, B₂, and B₆. Independently of sex and the level of physical activity, the women and men consumed insufficient quantities of vitamins B₁ and B₆, although this was not always related to increased values of corresponding activity coefficients.     

Carbohydrate Metabolism by the Acetic Acid Bacteria

Vitamin requirements for the growth of the acetic acid bacteria were investigated extensively on a. taxonomical viewpoint and the following new findings were pointed out. Neither Acetobacter nor Intermediate strain required vitamin for the growth.

Gluconobacter required generally pantothenic acid. And some strains belonging to it did moreover somewhat of thiamine, nicotinic acid and p-aminobenzoic acid, although there was a difference of requirements between strains even in the same species. Riboflavin, pyridoxine, vitamin B₁₂, folic acid, biotin and inositol were unnecessary for the growth of the acetic acid bacteria. A taxonomical division of the acetic acid bacteria based on the vitamin requirements agreed well with that on basis of the oxidative activities for carbohydrates.     

NUTRITIONAL REQUIREMENTS OF HAEMATOCOCCUS PLUVZALIS AND RELATED SPECIES1

All the described species and varieties of the genus Haematococcus were available. After isolation in pure culture they were used studying their nutritional requirements. H. buetschlii and H. droebakensis had already been shown by Droop to need vitamin B₁₂. H. capensis typ., H. capensis var. borealis, and H. zimbabwiensis were found to do so also. The 7 strains of H. pluvi-alis from various localities investigated showed slight physiological deviations, although morphologically they were so similar that they should not be described as varieties. A dilute inorganic nutrient solution with trace elements and iron kept in solution by EDTA was suitable either as such or supplemented with growth-promoting compounds. The growth was speeded by low concentrations of acetate and by enhancing photosynthesis. No strain of H. pluvialis absolutely required cobalamin, although it stimulated. Thiamine had a much more pronounced effect; for some strains it was indispensable. Although the response varies slightly from strain to strain, a luxuriant growth for all was obtained only with acetate and B₁, and usually enhanced by B₁₂. A peculiar feature of H. pluvialis is the catching up of cultures initially retarded by thiamine deficiency (probably due to slow B_l synthesis). When H. pluvialis multiplied fast its appearance differed from that considered typical: no red pigment and the cell wall not inflated. In nature it evidently lives under conditions unfavorable for good growth although suitable for survival in competition with other organisms.     

NUTRITION OF PLATYDORINA CAUDATA KOFOID

The vitamins p-aminobenzoic acid, thiamine, biotin, nicotinamide, and B₁₂ were tested for their ability to stimulate growth. Only vitamin B₁₂ was required. Urea and NaNO₂ supported excellent growth, although sodium nitrite, ammonium nitrate, and the Casamino acids supported only fair growth. Platydorina grew aerobically in the absence of an exogenous source of carbon; however a carbon source was required for anaerobic growth. Of 25 carbon compounds examined, isocitrate supported anaerobic growth in the light equalling the aerobic controls. Growth did not occur aerobically or anaerobically in the dark with any carbon source examined. Growth was excellent at pH values in excess of 7.0. Growth at pH 10.0 was 4 times that at 7.0 in strain I.U. 850 and twice that at 7.0 in strain Kan-3E. Growth was accelerated with the increase in temperatures but this increase may well be due to the increased intensity of light to which the cultures were exposed at the higher terperatures.     

The nature of the requirement of Saccharomyces carlsbergensis for vitamin B6

Saccharomyces carlsbergensis 4228, an organism widely used for determination of vitamin B₆, grows well without this vitamin if thiamine is also omitted from the basal medium, and an inoculum grown in a thiamine-low medium is used. Thiamine inhibits growth when added to such a medium. The thiazole moiety of thiamine, but not the pyrimidine, is also inhibitory, but less so than thiamine itself.Growth inhibition by thiamine is prevented by vitamin B₆. At low concentrations of thiamine, the amount of vitamin B₆ required for growth increases with the thiamine concentration; at concentrations of thiamine above 1 μg./10 ml. the vitamin B₆ requirement for growth remains essentially constant. Since these higher concentrations of thiamine have been used in methods that utilize this organism for determination of vitamin B₆ (1,2), the validity of these methods is confirmed.In the presence of thiamine, growth was also permitted by additions of the thiamine antagonist, neopyrithiamine. In this case, however, the relationship was fully competitive; i.e., the amount of neopyrithiamine required for growth increased regularly with the thiamine concentration. At concentrations considerably higher than those required for growth, neopyrithiamine again inhibited growth, and this inhibition was prevented by an increase in the thiamine concentration. Thus neopyrithiamine acts by lowering the effective thiamine concentration to subinhibitory levels; if excessive amounts are used, it prevents essential metabolic functions of thiamine and itself becomes toxic. The mechanism by which vitamin B₆ prevents thiamine toxicity is not known.The appearance of a requirement for certain growth factors because of inhibitory effects of other metabolically important compounds, rather than because of an intrinsic inability of the organism to synthesize the growth factor, may be much more common than the few recorded instances of this phenomenon indicate.     

Polymorphism of vitamin B12 [57Col binding proteins in rabbit serum

When rabbit serum labelled with vitamin B₁₂[⁵⁷Co] was subjected to starch gel electrophoresis and au;oradiography, three phenotypes of proteins capable of binding vitamin B₁₂ were observed. Family data revealed that these phenotypes (called TC-A, TC-AB and TC-B) are controlied by two codominant alleles (TC^A and TC^B), at an autosomic locus. Proteins capable of binding vitamin B₁₂ both in vivo and in vitro are commonly referred to as Transcobalamins and can be found in the serum of numerous animal species (for a review, see Glass, 1974; Allen, 1975; Stenman, 1975). Furthermore, Daiger et al. (1975a) have described seven different patterns of vitamin B₁₂ binding proteins which occur in human plasma and which are presumably controlled by four alleles. The present paper describes experiments in which both starch gel electrophoresis and autoradiography are used to identify three phenotypes of rabbit serum proteins responsible for binding vitamin B₁₂ in vitro. It was found that these three phenotypes are controlled by two allelic codominant genes, at an autosomic locus. Individual serum samples (30 μl), obtained from 385 White New Zealand rabbits varying in age from one month to three years, were incubated with 0.1 ng of vitamin B₁₂[⁵⁷Co] (specific activity: 180 μCi/μg; Lot 247; Radiochemical Centre, Amersham, England) at 37°C for 30 minutes. Starch gel electrophoresis and autoradiography were performed as described by Geldermann (1970) and Daiger et al. (1975b), respectively. Electrofocusing (pH range 3.5–9.5) was conducted in the 2117 Multiphor apparatus (LKB, Bromma, Sweden) according to the manufacturer's instructions. The resulting pH gradient was measured with a surface pH electrode (Ingold, Zürich, Switzerland).     

THE NEWER HEMATINICS,THEIR USE AND ABUSE

The newer hematinics are merely refinements of preexisting forms of treatment, but they have aided particularly in a better understanding of the deficiency states. The intrinsic factor of Castle has not been isolated from the gastric juice, and the interrelationships of this substance with the extrinsic factor (vitamin B₁₂) and folic acid have not been defined at this time. Vitamin B₁₂ appears to be the active principle of refined liver extract and alone is probably adequate treatment for pernicious anemia. The other varieties of megaloblastic anemia may result from deficiency of vitamin B₁₂ or folic acid, although generally treatment with the latter brings about complete and lasting remission.The use of multihematinics and multivitamin preparations containing folic acid is to be condemned, particularly because of the possibility of their obscuring anemia and thwarting diagnosis of pernicious anemia until neurologic complications have taken place.Saccharated oxide of iron is a relatively safe preparation for intravenous administration, but the indications for its use are few. Because the body has no mechanism for iron excretion, only the amount of iron necessary to make up a deficiency should be given, although there is no definite evidence that hemochromatosis results from overdosage.     

Nutrition of Volvulina Playfair*

SYNOPSIS. Vitamin B₁₂, biotin and thiamine requirements of 10 strains of Volvulina steinii and 1 strain of V. pringsheimii were studied. Vitamin B₁₂ is required for growth of both species, thiamine stimulates growth slightly, and biotin has no discernible effect on growth. The minimum concentration of vitamin B₁₂ giving a growth response in V. steinii, strain SC-2, was 10^?8 g/ml, and maximum growth response was obtained with 1.1 × 10^?7 g/ml. An organic carbon source is required for growth of V. steinii but not of V. pringsheimii. Growth of V. steinii, strain SC-2, occurred in 20 of 21 carbon sources tested. Optimal growth with each carbon source was largely dependent upon pH. Except for pyruvate, acetate, and ethanol, carbon source utilization was light-dependent, and growth in ethanol was reduced in the dark. Isocitric lyase activity was detected in V. steinii grown on acetate medium.     

NUTRITIONAL REQUIREMENTS OF HAEMATOCOCCUS PLUVIALIS AND RELATED SPECIES1

All the described species and varieties of the genus Haematococcus were available. After isolation in pure culture they were used studying their nutritional requirements. H. buetschlii and H. droebakensis had already been shown by Droop to need vitamin B₁₂. H. capensis typ., H. capensis var. borealis, and H. zimbabwiensis were found to do so also. The 7 strains of H. pluvialis from various localities investigated showed slight physiological deviations, although morphologically they were so similar that they should not be described as varieties. A dilute inorganic nutrient solution with trace elements and iron kept in solution by EDTA was suitable cither as such or supplemented with growth-promoting compounds. The growth was speeded by low concentrations of acetate and by enhancing photosynthesis. No strain of H. pluvialis absolutely required cobalamin, although it stimulated. Thiamine had a much more pronounced effect; for some strains it was indispensable. Although the response varies slightly from strain to strain, a luxuriant growth for all was obtained only with acetate and B₁, and usually enhanced by B₁₂. A peculiar feature of H. pluvialis is the catching up of cultures initially retarded by thiamine deficiency (probably due to slow B₁ synthesis). When H. pluvialis multiplied fast its appearance differed from that considered typical: no red pigment and the cell wall not inflated. In nature it evidently lives under conditions unfavorable for good growth although suitable for survival in competition with other organisms.     

THE EFFECT OF VITAMIN B12 ON THE ANEMIA AND COMBINED SYSTEM DISEASE OF ADDISONIAN PERNICIOUS ANEMIA

The effect of the parenteral administration of vitamin B₁₂ has been observed in eight patients with Addisonian pernicious anemia.Vitamin B₁₂ in initial doses of 50 micrograms or 25 micrograms induced satisfactory reticulocyte response and a return of erythrocyte count to within normal range in 60 days.In only two of the patients were secondary reticulocyte responses induced on a second injection of vitamin B₁₂.Concurrently with the hemopoietic response, the bone marrow changed from megaloblastic hyperplasia to normoblastic distribution.The paresthesias associated with combined system disease as well as disturbances in position sense and locomotor function may be entirely relieved or greatly diminished following injections of vitamin B₁₂.Maintenance injections of vitamin B₁₂ may be from 30 to 50 micrograms at intervals of one month, the amount depending upon the individual case.Vitamin B₁₂ may be used without untoward symptoms in patients previously sensitive to liver extract.     

UPTAKE OF COBALT AND VITAMIN B12 BY TROPICAL MARINE MACROALGAE1,2

Using gamma spectroscopy, measurements were made of the uptake of cobalt and vitamin B₁₂ by a number of species of tropical macroalgae, particularly Laurencia corallopsis and Enteromorpha lingulata. Data were gathered on the manner in which uptake rates are influenced by illumination and how they change with time during incubation and with substrate concentration. Some information is included on uptake rates when cobalt and vitamin B₁₂ were provided separately and together.     

Purification of 7-Keto-8-aminopelargonic Acid-7,8-Diaminopelargonic Acid Aminotransferase,an Enzym Involved in Biotin Biosynthesis,from Brevibacterium divaricatum

Vitamin B₆ is synthesized by green Cytisus scoparius callus and green Phellodendron amurense callus cultured on Linsmaier and Skoog Agar-medium with 10^?5m of ±-naphthaleneacetic acid (NAA) and 10^?6 m of 6-benzyladenine (BA). Even when thiamine and inositol were omitted from this medium, the growth and vitamin B₆ content of Cytisus scoparius callus did not change. Vitamin B₆ contents of clones of the calluses varied and were unstable during long-term subculture. Clonal selection was repeated to obtain stable strains with high vitamin B₆ content, and the vitamin B₆ content of one strain of green Cytisus scoparius callus became 4-times higher than that of the green leaves.     

Synthesis,physico-chemical properties and effect of adenosine thiamine triphosphate on vitamin B1 metabolism in the liver of alloxan diabetic rats

BackgroundAdenosine thiamine triphosphate (AThTP) is a nucleotide discovered in bacteria and some other living organisms more than a decade ago. No biochemical function for AThTP has been established yet, however, experimental data available indicate its possible involvement in metabolic regulation or cell signaling. Metabolism of AThTP in mammals, as well as the feasibility of its pharmacological application, is essentially unstudied.MethodsPreparative low-pressure chromatography was employed to purify chemically synthesized AThTP with its further analysis by mass spectrometry, HPLC, UV and fluorescence spectroscopy. Enzyme activity assays along with HPLC were used to examine the effects of AThTP and thiamine on vitamin B₁ metabolism in the liver of alloxan-induced diabetic rats.ResultsAn improved procedure for AThTP synthesis and purification is elaborated. Solution stability, optical spectral properties and the molar absorption coefficient for AThTP were determined. The levels of thiamine compounds were found to be increased in the liver of diabetic rats. Neither AThTP nor thiamine treatment affected hepatic vitamin B₁ metabolism. Fasting blood glucose concentration was also unchangeable after AThTP or thiamine administration.General significanceContrast to the widespread view about thiamine deficiency in diabetes, our results clearly shows an adaptive increase in the level of B₁ vitamers in the liver of alloxan diabetic rats with no further rising after AThTP or thiamine treatment at a moderate dose. Neither AThTP nor thiamine is effective in glycaemic control. These findings are to be considered in future studies dealing with thiamine or its analogues application to correct metabolic disturbances in diabetes.