Pantothenic acid blood

Relatively Httie is known about the bioavailabiUty of pantothenic acid in human beings, and only approximately 50% of pantothenic acid present in the diet is actually absorbed (10). Liver, adrenal glands, kidneys, brain, and testes contain high concentrations of pantothenic acid. In healthy adults, the total amount of pantothenic acid present in whole blood is estimated to be 1 mg/L. A significant (2—7 mg/d) difference is observed among different age-group individuals with respect to pantothenic acid intake and urinary excretion, indicating differences in the rate of metaboHsm of pantothenic acid. 

Rice bran is the richest natural source of B-complex vitamins. Considerable amounts of thiamin (Bl), riboflavin (B2), niacin (B3), pantothenic acid (B5) and pyridoxin (B6) are available in rice bran (Table 17.1). Thiamin (Bl) is central to carbohydrate metabolism and kreb s cycle function. Niacin (B3) also plays a key role in carbohydrate metabolism for the synthesis of GTF (Glucose Tolerance Factor). As a pre-cursor to NAD (nicotinamide adenine dinucleotide-oxidized form), it is an important metabolite concerned with intracellular energy production. It prevents the depletion of NAD in the pancreatic beta cells. It also promotes healthy cholesterol levels not only by decreasing LDL-C but also by improving HDL-C. It is the safest nutritional approach to normalizing cholesterol levels. Pyridoxine (B6) helps to regulate blood glucose levels, prevents peripheral neuropathy in diabetics and improves the immune function. 

The assay for pantothenic acid in whole blood, serum, urine, and cerebrospinal fluid is described here. Lactobacillus plantarum ATCC No. 8014 (formerly L. arabinosus) is used for the assay. The basal medium for assay (Table 2) is made up in double strength 2.5-ml portions of the medium are distributed into 10-ml borosilicate micro-Fembach flasks provided with aluminum caps (H18). Solutions to be assayed are added and distilled water used to bring the volume to 5 ml. The techniques for maintenance and assay are the same as those for L. casei (B12). Full growth at 37° takes 3 days. 

Citrated blood is diluted 1 10 with enzyme buffer solution, and preservative is added (H19). The buffer is prepared by dissolving 0.2 g of Clarase (Fisher Scientific Co., New York) in 100 ml citrate buffer (5 g potassium citrate monohydrate and 1 g citric acid monohydrate in 1000 ml distilled water, pH 5.6). The solution is incubated for 3 days at 37°. After incubation, it is autoclaved 15 minutes to stop enzymatic action and coagulate proteins. It is filtered, and 1.0, 1.5, and 2.0 ml of the supernatant is added to individual flasks and assayed. Control flasks are included to estimate pantothenic acid contamination of the enzyme. 

The range of pantothenic acid in normal blood and in cerebrospinal fluid is approximately the same (Table 3) in the urine it is higher. Ninety-nine... 

Pantothenate in blood and tissues is bound (R9) and released by autolysis or hydrolysis. More vitamin could be released by use of an alkaline phosphatase and an enzyme from avian liver (L6). This method liberates pantothenate from coenzyme A in a variety of foods and tissues (N3, N4). A comparison of hydrolytic methods in blood suggested autolysis to be the most advantageous method (N3) in our hands, treatment with Clarase gave more reliable results as compared with autolysis, acid hydrolysis, treatment with Mylase P, or combination of Clarase and papain, or liver enzyme and alkaline phosphatase. In urine, pantothenic acid is unbound our results show no increase with Clarase treatment. The vitamin has presumably a low threshold. Pantothenic acid shows the same concentration in blood and cerebrospinal fluid. 

Red blood cells contain pantothenic acid, 4 -phosphopantothenic acid, and pantetheine. These seem to enter by diffusion, and their function is not known unsurprisingly, because they contain no mitochondria, erythrocytes do not contain CoA (Annous and Song, 1995). The permeability of erythrocytes to pantothenate is normally relatively low, but in red cells infected with malaria parasites, the permeability is increased considerably the vitamin is taken up and utilized by the parasites, which require CoA (Saliba et al., 1998). 

Sauberlich (1974) suggested that a whole blood total pantothenic acid below... 

Annous KF and Song WO (1995) Pantothenic acid uptake and metabolism by red blood cells of rats. Journal of Nutrition 125,2586-93. 

Zempleni J, Steven Stanley J, and Mock DM (2001) Proliferation of peripheral blood mononuclear cells causes increased expression of the sodium-dependent multivitamin transporter gene and increased uptake of pantothenic acid./owma/ of Nutritional Biochemistry 12, 465-73. 

Vitamin E, while not necessary for health, seems to be required for the reproduction and lactation of animals. Niacin, a member of the B group of vitamins, is necessary for the prevention of the deficiency disease pellagra. Pantothenic acid, inositol, />-aminobenzoic acid, and biotin are substances involved in the process of normtl growth. Vitamin K is a vitamin that prevents bleeding, by assisting in the process of dotting of the blood. 

Plasma and urinary levels of pantothenic acid have been measured in dietary surveys as well as in controlled studies of the vitamin deficiency. One fairly recent study with human subjects involved the feeding of a pantothenic acid-free diet for 9 weeks. The urinary pantothenic acid levels (4-6 mg/day) in vitamin-sufficient subjects were roughly half that of the intake (10 mg/day). With consumption of the vitamin-free diet, urinary pantothenic acid levels gradually declined to about 0.8 mg/day over the 9-week period (Fry et ai., 1976). Both urinary and blood serum levels of pantothenate have been used to assess dietary status. Values from urinary measurements seem to be somewhat better correlated with intake of this vitamin, than blood measurements data (Berg, 1997). 

Pantothenic acid has also been called vitamin Bf. Excellent sources of the vitamin ore liver. egg.s. and cereals. It is found, however, in the form of CoA. This coenzyme cannot be absorbed directly from the gut. Although no experiments have been conducted in humans, studies on animals indicate that the coenzyme must be hydrolyzed to panthenene and pantothenate. " which arc absorbed by passive diffusion. Human intestinal cells contain enzymes tltat can hydrolyze the coenzyme. Pantothenate is the major form circulating in the blood and is absorbed by individual cells. Once inside ihe cell. CoA is synthesized. 

There are no convenient or reliable functional tests of pantothenic acid status, thus assessment is made by direct measurement of whole blood or urine pantothenic acid concentrations. Urine measurements are perhaps the easiest to conduct and interpret, and concentrations are closely related to dietary intake, Whole blood measurements are preferred to plasma, which contains only free pantothenic acid and is insensitive to changes in pantothenic acid intake. Concentrations of pantothenic acid in aU of the above fluids can be measured by microbiological assay, most commonly using Lactobacillus plantarum. Whole blood must first be treated with an enzyme preparation to release pantothenic acid fi om CoA. Other techniques that have been used to measure pantothenic acid in human samples include radioimmunoassay and gas chromatography, Other techniques that have been developed include gas chromatography-mass spectrometry and a stable isotope dilution assay. CoA and AGP can be measured by enzymatic methods. ... 

Urinary excretion of pantothenic add of less than 1 mg/day is considered abnormally low. Suspicion of inadequate intalce is further supported if whole blood levels are less than lOOpg/L, A guidance reference interval for pantothenic acid in whole blood or serum is 344 to 583(ig/L (1,57 to 2.66pmol/L), and for urinary excretion is 1 to 15 mg/day (5 to 68 uLmol/day). ... 

Rychlik M. Quantification of free and bound pantothenic acid in foods and blood plasma by a stable isotope dilution assay. J Agric Food Chem 2000 48 1175-81. 

Wyse BW, Wittwer C, Hansen RG. Radioimmunoassay for pantothenic acid in blood and other tissues. Clin Chem 1979 25 108-10. 

---