QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Lopez, H. W. Articles by Rémésy, C. Search for Related Content PubMed PubMed Citation Articles by Lopez, H. W. Articles by Rémésy, C.

---

Article

Dietary Phytic Acid and Wheat Bran Enhance Mucosal Phytase Activity in Rat Small Intestine¹

Unité de Laboratoire pour l’Innovation dans les Céréales, ZAC "Les Portes de Riom," BP 173, F-63204 Riom, France and ^* Laboratoire Maladies Métaboliques et Micronutriments, Centre de Recherches en Nutrition Humaine Auvergne, I.N.R.A. Clermont-Fd/Theix, F-63122 St-Genès-Champanelle, France

²To whom correspondence should be addressed.

	ABSTRACT

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 
The aim of this work was to investigate the influence of dietary phytic acid (PA) on intestinal phytase activity in growing rats by in vitro determination of phytase activity in the three segments of the small intestine (duodenum, jejunum and ileum), and by in vivo intestinal perfusion of a solution rich in PA (diluted soymilk). Using the in vitro method, duodenal and jejunal activities were enhanced significantly by adaptation to purified PA (+44 and +145% respectively, compared with control rats). For the rats adapted to the wheat bran (WB) diet, the induction of intestinal phytase by the substrate compared with the control values (P < 0.001) was observed only in ileum. Using soymilk in perfusions, rats consuming PA or WB diets hydrolyzed more phytate (P < 0.001 and P < 0.05, respectively) than controls. Further, Mg absorption from diluted soymilk was not affected by food adaptation, whereas Ca absorption was greater in the PA and WB groups (P < 0.001 and P < 0.05, respectively) than in the control group. Thus, intake of pure PA by rats enhances phytase in the upper parts of the small intestine (duodenum and jejunum), whereas the WB diet activates ileal phytase. Furthermore, the induction of phytase activity is greater in magnitude in rats fed synthetic PA than that observed in rats fed the WB diet. The enhancement of phytase improves intestinal Ca absorption, thus showing the capacity of the small intestine to adapt to diets rich in PA and poor in Ca.

KEY WORDS: • absorption • calcium • degradation • magnesium • phytate • rats

	INTRODUCTION

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 
Phytic acid (PA)³ or myo-inositol hexakisphosphate is a common constituent of plants; it is stored largely as a complex salt of Mg²⁺, K⁺, together with proteins within subcelllular single-membrane particles in grains and seeds. This molecule is an inhibitor of mineral absorption because the negative charges of the phosphate groups form insoluble salts upon interaction with di- and trivalent cations. Phytate thus causes deficiencies in minerals such as Ca, Fe and Zn when present in excess in the human diet (Maga 1982 ). To improve mineral bioavailability, PA levels may be decreased by phytase, an enzyme that catalyzes the stepwise hydrolysis of phytate to phosphate and inositol via penta- to monophosphates. Three sources of phytase are found in the gastrointestinal (GI) tract, i.e., dietary plant phytases, phytases from gut microflora and intestinal mucosal phytases. In fact, the PA breakdown in the stomach and small intestine of humans is influenced mainly by dietary phytase, whereas intestinal phytase activity is very low (Iqbal et al. 1994 , Sandberg and Andersson 1988 ). Even if no adaptation to increased small intestinal phytate degradation seems to occur in rats and humans (Brune et al. 1989 , Larsen 1993 , Sandberg et al. 1987 ), Moore and Veum (1983) showed that rats fed a marginal phosphorus diet can compensate for the lack of available phosphorus by a greater degradation of PA. The underlying mechanism has been interpreted as adaptation in the intestinal microflora; however, the role of the GI microflora in PA breakdown is controversial. Some authors observed that microflora in the GI tract are involved in phytate destruction in rats (Lopez et al. 1998 and 2000 , Wise and Gilburt 1987 ), whereas another group suggested that microflora do not play a major role in phytate degradation in rats (Miyazawa et al. 1996 ). Although GI microflora are likely to be factors influencing intestinal PA breakdown, they cannot explain entirely the gradual increase of intestinal phytase activity during the development of rats (Rao and Ramakrishnan 1986 ). Yang et al. (1991b) showed that the intestinal phytate-degrading enzyme was formed by 70K and 90K subunits that are expressed differently. The 70K subunit is detected at birth, whereas the 90K subunit appears at the weaning period, and the induction of the 90K subunit seems to be accelerated by PA intake (Yang et al. 1991a )

The aim of this work was thus to investigate the influence of dietary PA (provided pure or included in wheat bran) on the intestinal phytase activity in growing rats by the following two methods: 1) in vitro determination of phytase activity in the three segments of the small intestine (duodenum, jejunum and ileum), and 2) in vivo response to intestinal perfusion of a solution rich in PA (diluted soymilk)

	MATERIALS AND METHODS

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 
Animals and diets.

Male Wistar rats (n = 112), weighing ~150 g, were used. They were derived from the colony of laboratory animals of the National Institute of Agronomic Research (I.N.R.A., Clermont-Ferrand/Theix, France). All rats were allowed free access to food and distilled water. The rats were housed two per cage (wire-bottomed to limit coprophagy) and maintained in a temperature-controlled room (22°C) with a dark period from 2000 to 0800 h. For 6 d before the experiment, all rats were fed the control diet (Table 1 ). After this period, 16 rats were sampled (d 0 of the experiment) as follows: 8 rats were used for the in vitro determination of intestinal phytase activity and the others were perfused with diluted soymilk. The remaining rats were divided into three groups as follows: 1) 32 rats were fed the control diet (C group); 2) 32 rats were fed the phytic acid diet (PA group); and 3) 32 rats were fed the wheat bran diet (WB group). At d 10 and 20, 16 rats of each group were killed (8 rats for in vitro determination of intestinal phytase; the other 8 were perfused with soymilk). Daily food consumption and body weight were recorded twice a week. Animal handling procedures were approved by Institutional Ethics Committee of the INRA (Clermont-Ferrand, France), in accordance with decree n°87–848.

For the determination of intestinal phytase activity (Biehl and Baker 1997 ), rats were killed by cervical dislocation. The three segments of the small intestine (duodenum, jejunum and ileum) were separated. The lumen of each segment was immediately flushed with ice-cold saline (7.5 g/L NaCl) and then cut longitudinally to expose brush border cells. The brush border cells were gently scraped off with a glass microscope slide and immediately frozen in liquid nitrogen, after which the cells were kept at -80°C until analysis could be performed.

After thawing for a short period of time, each mucosal sample (200 mg wet weight) was homogenized in 10 mL cold sucrose (50 mmol/L)-Tris HCl (2 mmol/L) buffer (pH 7.1) containing 100 mg/L Tween 20. Homogenization was performed with a Potter-Elvejhem homogenizer (Braun, Melsungen, Germany) at moderate speed. At each time, the tube and the homogenizer were washed with 70% ethanol and then rinsed with deionized water. The tissue homogenates were centrifuged at 8000 x g for 3 min and the supernatant was then separated from the pellets. The protein content of the supernatant was determined using the Pierce BCA reagent kit (Interchim, Montluçon, France).

To measure phytase activity, the supernatant (2 mL) was combined with 100 µL of 40 mmol/L magnesium chloride solution and 100 µL of 4 mmol/L zinc chloride solution. An antibiotic mixture was added to provide 130,000 U of streptomycin and 2 x 10⁶ U penicillin/L of substrate. This was done to minimize microbial phytase activity. A 30 mmol/L sodium phytate solution (100 µL) was then added to the experimental tubes, and deionized water was added to the blanks. Reagent blanks consisting of buffer with or without sodium phytate together with antibiotics were included. Tubes were then incubated at 37°C in a water bath for 2 h, after which an aliquot was taken for determination of inorganic phosphate (Pi) by a commercial kit (Biotrol, Paris, France).

Intestinal perfusion of soymilk.

Rats were anesthetized with sodium pentobarbital (40 mg/kg body) 18 h after food removal and maintained alive during the perfusion period on a hot plate at 37°C. A perfusion of the small intestine (2 cm distal from pylorus to the valvula ileocecalis) was prepared by installing cannulas (o.d. 4 mm, i.d. 2.5 mm) at each extremity. The small intestine was perfused continuously in situ with a solution rich in phytic acid at a flow rate of 1 mL/min, at 37°C for 30 min. To obtain a PA concentration close to 1 mmol/L in the perfused solution, soymilk (Bjorg, St Genis, France) was diluted with 100 mmol/L NaCl and adjusted to pH 6.7. An aliquot of effluent was collected directly at the exit of the ileum into plastic tubes (2 mL) during the last 5 min of perfusion. Perfusate samples were then stored at -20°C.

Analytical procedures.

    Ca and Mg determinations. Samples of soymilk were dry-ashed (10 h at 500°C). The resulting residues were extracted with 5 mol/L HCl and made up to an appropriate volume with 1 g/L lanthanum chloride solution. Mineral concentrations were determined by atomic absorption spectrophotometry (Perkin-Elmer 420, Norwalk, CT) in an acetylene-air flame at the following wavelengths: 422 nm (Ca) and 285 nm (Mg). Appropriate quality controls were run with each set of measurements.

Phytic acid in soymilk was determined using a high performance ion chromatographic (HPIC) method (Dionex, Sunnyvale, CA) as described previously (Lopez et al. 2000 ). The HPIC system consisted of a gradient pump (Dionex series 4500) equipped with a 25-µL injector loop and a Dionex HPIC AS-11 analytical column (0.5 cm i.d. x 25 cm). An anion micromembrane suppressor was used for conductivity detection. Samples in the range of 2 mL were extracted with 4 mL of 0.65 mol/L HCl under vigorous mechanical agitation (Ika-Werk HS 500, Staufen, Germany) for 4 h at room temperature. The extracts were centrifuged at 5000 x g, and 2 mL of the supernatant were diluted to 10 mL with deionized water (Millipore water system). The diluted supernatant was passed through a 200- to 400-mesh AG 1-X8 chloride anion exchange column (Bio-Rad, Richmond, CA). The columns were washed with 15 mL of 0.025 mol/L HCl and phytic acid was eluted from the resin with 15 mL of 2 mol/L HCl. The eluates were evaporated to evaporator concentrator (Jouan SA, St Herblain, France) and resuspended in deionized water. Potassium phytate (Sigma, St. Louis, MO) was used as the external calibration standard.

Statistical analysis.

Values are given as the means ± SEM Results were compared by two-way ANOVA using the General Linear Models procedure of the SuperANOVA software (Abacus, Berkeley, CA). Post-hoc comparisons were done by using Fisher’s least significant difference procedures. Differences among groups were considered significant if P < 0.05.

	RESULTS

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 
In vitro determination of intestinal phytase activity.

Weight gain and mucosal tissue from control rats were not different from those of rats fed the PA or WB diet. Increasing doses of mucosal protein in tubes resulted in marked increases in release of Pi from sodium phytate (data not shown). Intestinal phytase activity also differed between the different segments of the small intestine (Table 2 ); in control rats, during the 20 d of the experiment, the upper part of the small intestine (duodenum) exhibited the maximal activity [between 10.64 and 11.51 nmol Pi released/(min · mg protein)], whereas the jejunum and the ileum had a moderate level of activity [1.06–1.45 nmol Pi released/(min · mg protein)]. In contrast to control rats, those adapted to the PA or WB diet had the highest capacity to release Pi from sodium phytate in the duodenum mucosa, but jejunum and ileum phytase activities varied significantly.

At d 20, phytase activities in the different sections of the small intestine remained at low values in rats fed the control diet. When the diet contained phytates, duodenal and jejunal activities were enhanced significantly by PA (+44 and + 145%, respectively, compared with control rats). For rats adapted to the WB diet, induction of the intestinal phytase by the substrate was observed only in ileum compared with the control values (P < 0.001)

Perfusion of diluted soymilk.

When the small intestine was perfused at a flow rate of 1 mL/min for 30 min with a diluted soymilk containing ~1 mmol/L of PA, the content of PA in the effluent collected at the extremity of the ileum was decreased even in rats adapted to a PA-free diet (Table 3 ). Thus, 22.8% of PA was metabolized by the intestinal wall. In fact, inositol pentakisphosphate and inositol tetrakisphosphate (dephosphorylated forms of PA) were identified in the effluent (data not shown). After 10 d of adaptation, the rate of PA breakdown remained stable in control rats, whereas the dietary PA intake significantly induced intestinal phytase. However, the degradation of phytate from soymilk in the small intestine was greater (P < 0.05) in rats adapted to the PA diet than in those adapted to the WB diet. At 20 d, intestinal phytase activity was unchanged in rats fed the control diet. The diets containing PA significantly enhanced intestinal phytase activity, i.e., rats consuming the PA or WB diet hydrolyzed more phytate from soymilk (P < 0.001 and P < 0.05, respectively) than control rats. In parallel, the evolution of Ca and Mg absorption from soymilk was evaluated (Table 4 ). Mg absorption was not affected by the composition of diet or by the intensity of PA degradation. In contrast, Ca absorption from soymilk was significantly higher in rats adapted to the PA or WB diet than in controls. At d 10, only the rats adapted to the PA diet had a significant increase in Ca absorption (P < 0.05). After 20 d of adaptation, Ca absorption from soymilk was greater in both the PA and WB groups (P < 0.001 and P < 0.05, respectively) than in the control group. It must be noted that stimulated Ca absorption occurred in the same rats that had an increased PA degradation.

	DISCUSSION

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

Using tissue homogenates, we found phytase activity in the rat small intestine comparable to that found by others (Iqbal et al. 1994 , Rao and Ramakrishnan 1985 ). In vitro determination of intestinal phytase activity showed that this latter is reduced in the lower intestine. This finding is in agreement with the results Maenz and Classen (1998) observed in chickens. However, the importance of the duodenum in total PA hydrolysis should be qualified. Duodenum is shorter than jejunum; thus the PA-brush border interaction may be limited in the upper part of the gut, altering PA breakdown. The in vitro method also emphasized that diet containing pure sodium phytate affected phytase in the upper parts of the GI tract (duodenum and jejunum), whereas the WB diet (providing the same quantity of PA) enhanced ileal activity. Furthermore, the finding that the intensity of the PA degradation in the small intestine was greater in rats fed the PA diet than in those consuming the WB diet was confirmed by the two methods. These differences between synthetic and natural PA may be explained in two ways. First, natural PA is stored in WB as a complex salt of Mg²⁺, K⁺, together with proteins within subcelllular single-membrane particles. Such complexes are considered to be less accessible by phytase than sodium PA. Thus, enzyme induction may be hindered by PA complex existing in WB. Second, in contrast to the PA diet, WB is rich in unavailable carbohydrates, which may reduce digestive transit, thus causing a PA accumulation in the distal parts of the small intestine. Therefore, there may exist a better contact between WB and mucosa in these parts, resulting in a more effective ileal phytase activity.

The phytase assay system in current use (Biehl and Baker 1997 ) was based on the enzymatic release of Pi from sodium phytate at pH 7.1. When using in vitro tissue homogenates, it is not possible to simulate completely conditions prevailing in the gut. In vivo intestinal perfusion reflects these conditions more accurately in a controlled manner. Because a stable synthetic solution containing 1 mmol/L purified PA was impossible to obtain, diluted soymilk was chosen for intestinal perfusion. The in vivo method validated the in vitro results, i.e., the adaptation of diets containing PA improved the degradation of soymilk phytate in the small intestine. Furthermore, rats adapted to a diet enriched in PA exhibited greater intestinal phytate hydrolysis from soymilk than those adapted to WB.

The perfusion model is also suitable to check the consequences of phytate degradation on Ca and Mg intestinal absorption. It is widely accepted that dietary PA inhibits Ca absorption (Lönnerdal et al. 1989 , Simpson and Wise 1990 ), and reduction of PA should significantly increase Ca availability (Bedford and Schulze 1998 ). In this study, because soymilk is rich in phytates and poor in Ca, it seems likely that PA hydrolysis observed in rats fed the PA or WB diets would in turn cause a rise in Ca bioavailability. On the other hand, it should be noted that the presence of Ca in the gut influences phytate hydrolysis. Thus, a high Ca/PA molar ratio in food leads to the absence of hydrolysis products in rat intestine (Wise et al. 1983 ). The reason for the decreased phytate degradation due to calcium may be the formation of insoluble calcium phytate complexes, which are poor substrates for phytase (Sandberg et al. 1993 ). We used Na-phytate, and K-/Mg-phytate (PA form in soymilk) for in vitro assay and for perfusion, respectively. In this way, it is conceivable that Pi release from Ca phytate would be different from that observed in our experiments.

In contrast to Ca, Mg absorption was not modified by the adaptation of phytase activity in the small intestine. In soymilk, the relative abundance of Mg and Ca may explain the difference observed because the Mg/PA ratio is more favorable for Mg intestinal absorption than the Ca/PA ratio. Furthermore, even if studies show deleterious effects of PA on Mg requirements (Miyazawa and Yoshida 1991 , Pallauf et al. 1998 ), unlike Ca, Fe or Zn, PA is not a major factor for Mg bioavailability. Indeed, plants rich in PA (such as whole cereal products, legumes or oilseeds) also contain large amounts of Mg. Under these conditions, unrefined foods remain the major source of Mg. Recent work (Levrat-Verny et al. 1999 ) has shown that the amount of absorbed Mg daily is enhanced significantly in rats fed a whole flour diet compared with those fed white flour diet.

A direct extrapolation of these results to humans may be premature because the ability of various species of monogastric animals to hydrolyze PA varies. Rats and chicks appear to have high intestinal phytase activity, whereas humans and pigs have a much lower activity (Biehl and Baker 1997 , Cooper and Gowing 1983 , Iqbal et al. 1994 , Pointillard et al. 1987 ). In spite of these differences, our study suggests that when the diet contains PA, the induction of mucosal phytase exists in rodents and perhaps in humans. The origin of dietary PA (isolated or as a component of a natural product) is also important for intestinal phytase activity. Pure PA ingestion by rats enhances the upper parts of the small intestine (duodenum and jejunum), whereas a WB diet activates the ileal phytase. In contrast to pure PA, WB is rich in unavailable carbohydrates, which reduce digestive transit, thus causing a PA accumulation in ileum. The accumulation may induce a better contact between WB and mucosa in this part, resulting in a more effective ileal phytase activity. Furthermore, the stimulation of phytase activity is more important in rats fed synthetic PA than that observed in rats fed the WB diet. Because natural PA is stored as a complex salt, enzyme induction may be hindered by the PA complex existing in WB. The enhancement of phytase leads to an improved Ca intestinal absorption, demonstrating the adaptation of the small intestine to diets rich in PA and poor in Ca. Human studies are required to confirm these encouraging results observed in rats.

	ACKNOWLEDGMENTS

 
We thank Catherine Besson and Stéphanie Moriceau for their assistance. We thank Jennifer Donovan and Timothy Taylor for their careful reading of the manuscript.

	FOOTNOTES

 
¹ Supported by A.N.R.T. (Agence Nationale pour la Recherche Technique), I.N.R.A. (Institut National de la Recherche Agronomique) and U.L.I.C.E. (Unité de Laboratoire pour l’Innovation des Céréales).

³ Abbreviations used: C, control; GI, gastrointestinal tract; PA, phytic acid; Pi, inorganic phosphorus; WB, wheat bran.

Manuscript received January 31, 2000. Initial review completed February 16, 2000. Revision accepted March 28, 2000.

	REFERENCES

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 

1. Bedford M. R., Schulze H. Exogenous enzymes for pigs and poultry. Nutr. Res. Rev. 1998;11:91-114

2. Biehl R. R., Baker D. H. 1-Hydroxycholecalciferol does not increase the specific activity of intestinal phytase but does improve phosphorus utilization in both cecectomized and sham-operated chicks fed cholecalciferol-adequate diets. J. Nutr. 1997;127:2054-2059[Abstract/Free Full Text]

3. Brune M., Rossander L., Hallberg L. Iron absorption: no intestinal adaptation to a high phytate diet. Am. J. Clin. Nutr. 1989;49:542-545[Abstract/Free Full Text]

4. Cooper J. S., Gowing H. S. Mammalian small intestine phytase. Br. J. Nutr. 1983;50:673-678[Medline]

5. Iqbal T. H., Lewis K. O., Cooper B. T. Phytase activity in the human and rat small intestine. Gut 1994;35:1233-1236[Abstract/Free Full Text]

6. Larsen T. Dephytinisation of a rat diet: consequences for mineral and trace elements absorption. Biol. Trace Elem. Res. 1993;39:55-71[Medline]

7. Levrat-Verny M. A., Coudray C., Bellanger J., Lopez H. W., Demigné C., Rayssiguier Y., Rémésy C. Whole wheat flour ensures higher mineral absorption and bioavailability than white wheat flour. Br. J. Nutr. 1999;82:17-21[Medline]

8. Lönnerdal B., Sandberg A. S., Sandström B., Kunz C. Inhibitory effects of phytic acid and other inositol phosphates on zinc and calcium absorption in suckling rats. J. Nutr. 1989;119:211-214

9. Lopez H. W., Coudray C., Bellanger J., Levrat-Verny M. A., Demigné C., Rayssiguier Y., Rémésy C. Resistant starch improves mineral assimilation in rats adapted to a wheat bran diet. Nutr. Res. 2000;20:141-155

10. Lopez H. W., Coudray C., Bellanger J., Younes H., Demigné C., Rémésy C. Intestinal fermentation lessens the inhibitory effects of phytic acid on mineral utilization in rats. J. Nutr. 1998;128:1192-1198[Abstract/Free Full Text]

11. Maenz D. D., Classen H. L. Phytase activity in the small intestinal brush border membrane of the chicken. Poult. Sci. 1998;77:557-563[Abstract/Free Full Text]

12. Maga J. A. Phytate: its chemistry, occurrence, nutritional significance and methods of analysis. J. Agric. Food Chem. 1982;30:1-9

13. Miyazawa E., Iwabuchi A., Yoshida T. Phytate breakdown and apparent absorption of phosphorus, calcium and magnesium in germfree and conventionalized rats. Nutr. Res. 1996;16:603-613

14. Miyazawa E., Yoshida T. Effects of dietary levels of phytate and inorganic phosphate on phytate breakdown and absorption of calcium and magnesium in rats. Nutr. Res. 1991;11:797-806

15. Moore R. J., Veum T. L. Adaptive increase in phytate digestibility by phosphorus-deprived rats and the relationship of intestinal phytase (EC 3.1.3.8.) and alkaline phosphatase (EC 3.1.3.1.) to phytate utilization. Br. J. Nutr. 1983;49:145-152[Medline]

16. Pallauf J., Pietsch M., Rimbach G. Dietary phytate reduces magnesium bioavailability in growing rats. Nutr. Res. 1998;18:1029-1037

17. Pointillard A., Fourdin A., Fontaine N. Importance of cereal phytase activity for phytate phosphorus utilization by growing pigs fed diets containing triticale or corn. J. Nutr. 1987;117:907-913

18. Rao R. K., Ramakrishnan C. V. Inositol phosphatase in developing rat duodenum, jejunum and ileum. Biol. Neonate 1986;50:165-170[Medline]

19. Sandberg A.-S., Andersson H. Effect of dietary phytase on the digestion of phytate in the stomach and small intestine of humans. J. Nutr. 1988;118:469-473

20. Sandberg A.-S., Andersson H., Carlsson N. G., Sandström B. Degradation products of bran phytate formed during digestion in the human small intestine: effect of extrusion cooking on digestibility. J. Nutr. 1987;117:2061-2065

21. Sandberg A.-S., Larsen T., Sandström B. High dietary calcium level decreases colonic phytate degradation in pigs fed a rapeseed diet. J. Nutr. 1993;123:559-566

22. Simpson C. J., Wise A. Binding of zinc and calcium to inositol phosphates in vitro. Br. J. Nutr. 1990;64:225-232[Medline]

23. Wise A., Gilburt D. J. Caecal microbial phytate hydrolysis in the rat. Hum. Nutr. Food Sci. Nutr. 1987;41F:47-54

24. Wise A., Richards C. P., Trimble M. L. Phytate hydrolysis in the gastrointestinal tract of the rat followed by phosphorus-31 Fourier transform nuclear magnetic resonance spectroscopy. Appl. Environ. Microbiol. 1983;45:313-314[Abstract/Free Full Text]

25. Yang W. J., Matsuda Y., Inomata M., Nakagawa H. Developmental and dietary induction of the 90K subunit of rat intestinal phytase. Biochim. Biophys. Acta 1991a;1075:83-87[Medline]

26. Yang W. J., Matsuda Y., Sano S., Masutani H., Nakagawa H. Purification and characterization of phytase from rat intestinal mucosa. Biochim. Biophys. Acta 1991b;1075:75-82[Medline]

This article has been cited by other articles:

				H. Joung, B. Y. Jeun, S. J. Li, J. Kim, L. R. Woodhouse, J. C. King, R. M. Welch, and H. Y. Paik Fecal Phytate Excretion Varies with Dietary Phytate and Age in Women J. Am. Coll. Nutr., June 1, 2007; 26(3): 295 - 302. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Lopez, H. W. Articles by Rémésy, C. Search for Related Content PubMed PubMed Citation Articles by Lopez, H. W. Articles by Rémésy, C.