Intestinal Alkaline Phosphatase Activity Research Articles

Possible role of intestinal alkaline phosphatase activity in thiamine transport.

Thiamine deficiency caused a marked decrease of intestinal alkaline phosphatase (al-Pase) activity, but had no effect on the Ca++-ATPase activity and Ca++-absorption in rats. The al-Pase activity was significantly decreased 1 h after oral administration of ethanol at 0.5 and 2.5 g/kg. In contrast, Mg++-, Ca++-and (Na+ + K+)-ATPase activities did not change after the administration of ethanol. These findings show that the al-Pase activity, unlike the Ca++-ATPase activity, is not related to Ca++-absorption. A possible role of al-Pase activity in the active transport of thiamine in the intestine was discussed.

Independence of 1,25-dihydroxyvitamin D3-mediated calcium transport from de novo RNA and protein synthesis.

The administration of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) to rachitic chicks produces an increase in (a) RNA and protein synthesis, (b) calcium binding protein (CaBP) concentration, and (c) alkaline phosphatase activity in the duodenum. These events occur concomitantly with enhanced calcium transport. We inhibited RNA and protein synthesis in richitic chicks and measured the subsequent response to 1,25(OH)2D3. Actinomycin D, injected prior to and following 1,25(OH)2D3 administration, inhibited intestinal RNA polymerase activity, blocked the rise in serum calcium, reduced the amount of CaBP, and increased alkaline phosphatase activity. Cycloheximide injected in similar fashion, inhibited the 1,25(OH)2D3-mediated increase in intestinal protein synthesis, serum calcium, CaBP, and alkaline phosphatase activity. Neither inhibitor blocked the ability of 1,25(OH)2D3 to stimulate calcium transport as measured in isolated duodenal loops in vivo. The ability of either inhibitor to block 1,25(OH)2D3-mediated calcium transport despite inhibition of CaBP production and alkaline phosphatase activity (by cycloheximide) indicates that de novo RNA and protein synthesis, and in particular CaBP and alkaline phosphatase, are not required for the 1,25(OH)2D3 stimulation of calcium transport.

Influence of the thyroid and adrenal glands on the growth of the intestine of the suckling rat, and on the development of intestinal alkaline phosphatase and disaccharidase activities.

AbstractPrevious investigations have shown that cortisone or thyroxine can promote maturation of the intestinal epithelium in rats hypophysectomized at six days of age. This indication that either the thyroid or the adrenocortical hormone can act in the absence of the other has been pursued by study of intestinal maturation in rats deprived of the thyroid or adrenal glands during the suckling period. At 24 days of age, rats that have been thyroidectomized at six days retain the short villi and low mitotic index characteristic of neonatal life. Thyroxine elevates the mitotic index; neither thyroxine nor cortisone promote lengthening of the villi, but both cause some deepening of the crypts. Duodenal alkaline phosphatase and jejunal maltase remain at very low levels, but sucrase, which is absent at six days, does appear in the thyroidectomized pups at 24 days. Thyroxine raises phosphatase and maltae activity to the normal 24‐day level, but cortisone is only partly effective. Sucrase is raised above the normal maximum by cortisone but not by thyroxine. After adrenalectomy at 14 days, cortisone corrects deficiencies in villus height, crypt depth, and mitotic index, but thyroxine is without effect. Phosphatae, maltase, and sucrase activities rise only to subnormal levels in adrenalectomized pups. Thyroxine restores phosphatase activity to the control level, but is only partly successful in normalizing disaccharidase activities. Periodic acid‐Schiff stainability of the brush border is weak in specimens deprived of either thyroid or adrenals. Both thyroxine and cortisone restore normal intensity after thyroidectomy; after adrenalectomy only cortisone was able to restore normal stainability. Plasma corticosteroid concentration is elevated by thyroxine only if the hypophysis is present. These results demonstrate that the intestinal epithelium is able to respond to each hormone in the absence of the other.

Cytoplasmic Glucocorticoid Receptors in the Developing Small Intestine of the Rabbit Fetus

Glucocorticoid binding and alkaline phosphatase activity in the small intestine of the fetal rabbit were studied to investigate the relationship of glucocorticoid receptors and the development of the tissue. In the cytosol fraction, the binding of (3H)dexamethasone involves a macromolecule with high affinity (Kd = nM) for the hormone and a limited number of binding sites (saturable at a hormone concentration of 10 nM). That the binding reaction involves a protein and sulfhydryl groups was demonstrated by the absence of binding of the steroid in the presence of Pronase and sulfhydryl blocking reagents. In sucrose density gradients, the complexes have sedimentation coefficients of about 4S and 7S at low ionic strength, but only 4S at high ionic strength (0.4m KCl). The binding protein is thermolabile, and is stabilized by complexing with the hormone. The ability of different steroids to compete with (3H)dexamethasone for the binding sites correlates well with their glucocorticoid potency. During development of the fetal rabbit small intestine, the total number of glucocorticoid-binding sites in the cytosol increases in parallel with the increases in the tissue weight until term. However, the concentration of the binding sites (pmol/mg cytosol protein) is maximum at day 25 of gestation, followed by a decrease to the adult level within a few days after birth. Alkaline phosphatase activity is first detectable on day 25 of gestation and increases rapidly thereafter. These observations suggest that there may be a temporal relatioship between the development of the fetal rabbit small intestine, as reflected in the alkaline phosphatase and the levels of glucocorticoid receptors in the cytosol.

Experimental feline panleucopenia in the conventional cat.

Coventional kittens, 12-27 weeks old, were inoculated with cell-cultured feline panleucopenia virus and killed sequentially between day 3 and day 24 after inoculation. All developed a non-fatal mild disease between days 2 and 9, characterized by lymphopenia, neutropenia, listlessness, depression and the development of neutralizing antibodies to the virus. Small intestinal bacterial counts were reduced during the period of maximal clinical disease, presumably a result of decreased food intake. There was involution of the thymus with marked depletion of lymphocytes between days 3 and 12. Depletion of lymphocytes also characterized the lesions in the lymph nodes between days 3 and 8. At the same time crypt lesions with spotty distribution were in the small intestinal and colonic mucosa. The changes were loss of crypt epithelial cells with compensatory attenuation of the remaining epithelium. Electron microscopically, the number and size of microvilli and secretory granules were reduced but there was no change indicating lethal cell injury. There were no virus particles. The findings point to an early and transient cellular damage by the virus. Intestinal alkaline phosphatase activity disappeared from the luminal surface of the attenuated crypt epithelial cells. Otherwise, intestinal alkaline and acid phosphatase activity were not altered in inoculated cats.

Intestinal disaccharidase and alkaline phosphatase activities of jejunal biopsies in small bowel diseases of children (author's transl)

Intestinal disaccharidase activities were determined in 294 jejunal biopsies obtained from 254 children with various disorders of the small bowel, and alkaline phosphatase activity was measured in 251 biopsies. In normal mucosa a broad range of enzyme activity was found corresponding with the data in the literature. A primary disaccharidase deficiency was observed in 5 children with congenital sucrase-isomaltase deficiency and in a 12-year-old Egyptian boy with acquired lactase deficiency. A secondary generalized depression of disaccharidase activity and a diminution of alkaline phosphatase activity existed chiefly in patients who had severe or moderate mucosal damage, also in active coeliac disease and during gluten loading, in protracted diarrhoea of infancy, chronic malabsorption of unknown origin and agammaglobulinemia. During remissions enzyme activities recovered together with mucosal improvement. Low levels of enzyme activities were also seen in some cases of protracted diarrhoea of infancy and chronic malabsorption of unknown origin although only mild mucosal lesions were demonstrated.

Chemical Inhibition Method for Alkaline Phosphatase Isoenzymes in Human Serum

The authors adapted a chemical inhibition procedure using L-phenylalanine and urea as specific inhibitors to quantitate the activities of bone, liver, and intestinal alkaline phosphatase (ALP) isoenzymes in human serum. The results of this assay were compared with electrophoretic separation, gamma-glutamyl transpeptidase (GGTP) activity, and the clinical setting in a group of patients with elevated total ALP activity. In addition, expected ranges of serum ALP isoenzymes for healthy young men and also for a geriatric population are presented.

Influence of exocrine and endocrine pancreatic function on intestinal brush border enaymatic activities.

Digestive enzymatic activities (disaccharidases, alkaline phosphatase, peptide hydrolases) have been determined in the mucosa of 14 patients with chronic pancreatitis. All had an abnormal secretin-pancreozymin test. Four patients had insulin-dependent diabetes mellitus, four a pathological glucose tolerance test. Nine patients had steatorrhoea. Maltase, sucrase, and alkaline phosphatase activity was significantly elevated in patients with exocrine pancreatic insufficiency, whereas those of lactase, trehalase, and peptide hydrolase were normal. Patients with steatorrhoea had higher maltase and sucrase activity than those without steatorrhoea, whereas decreased glucose tolerance had no effect on brush border enzymatic activity. It is suggested thatdecreased exocrine rather than decreased endocrine pancreatic function is responsible for the increase in intestinal disaccharidase and alkaline phosphatase activity, possible by the influence of pacreatic enzymes on the turnover of brush border enzymes from the luminal side of the mucosal membranes or by direct hormonal stimulation though cholecystokinin.

In vitro stimulation of apparent intestinal alkaline phosphatase activity by thyrocalcitonin

The effect of thyrocalcitonin (TCT) on alkaline phosphatase activity in intestinal brush borders has been studied in vitro. The hormone strongly stimulates the enzymatic activity at pharmacological doses. Because of the importance of alkaline phosphatase in intestinal calcium absorption, evidence is presented which suggests a possible role of TCT in this process.

The effects of polychlorinated biphenyls on calciferol (vitamin D) mediated calcium metabolism

Polychlorinated biphenyl compounds which are environmental pollutants of industrial origin have been linked to some of the ecological hazards attributed to other chlorinated hydrocarbons. This report examines the effect of polychlorinated biphenyl pretreatment on calcium metabolic events which are mediated by vitamin D (calciferol). Rachitic birds were given two commonly used polychlorinated biphenyl compounds, Aroclor 1254 and 1260, 1 mg/day, for 7 days before intestinal calcium transport in vivo and in vitro, intestinal alkaline phosphatase activity, and bone calcium mobilization were assayed. The normal calciferol-mediated increase in intestinal calcium transport both as measured in vivo and in vitro, was significantly inhibited by PCB pretreatment. However, intestinal alkaline phosphatase activity and bone calcium mobilization were not altered by polychorinated biphenyl pretreatment. These results show that polychlorinated biphenyl intervenes in calciferol-mediated calcium metabolism in a somewhat different manner than those results observed following DDT pretreatment ( Nowicki et al., J. Agr. Food Chem. 20, 376, 1972 ), in which both the alkaline phosphatase and bone calcium mobilization responses were also inhibited. These data may furnish a partial explanation for the possible involvement of polychlorinated biphenyl in contributing to altered calcium metabolism and subsequent reproductive failure of some avian species.

Changes in Intestinal Lactase and Alkaline Phosphatase Activity Levels with Age in the Baboon (Papio Papio)

There has been debate about possible etiologies of low intestinal lactase levels in human subjects with primary lactose malabsorption. Data on other primates are not available; therefore a study of baboons was undertaken. Eight Olive baboons ( Papio papio ) from the same colony were killed at 1, 2, 3, 4, 8, 9, 12, and 36 months of age. The small intestines were divided into 10 equal segments and assayed for disaccharidase, alkaline phosphatase, and leucyl naphthylamidase activities. In comparison with the 1- to 4-month-old animals, lactase and cellobiase values were less in the duodenum and ileum in the 8- to 12-month-old animals, and lowest all along the intestine of the 36-month-old animal. Alkaline phosphatase activity was highest in the 1- to 4-month-old animals, and, after this age, was usually less than half that present in the younger animals. Sucrase, maltase, palatinase, trehalase, and leucyl naphthylamidase activities were essentially similar at all ages. The lower levels of lactase, cellobiase, and alkaline phosphatase in the older animals, in comparison to the 1- to 4-monthold baboons, appear to be a selective age-related phenomen.

Pitfalls in histochemical localization studies of NADPH generating enzymes or enzyme systems in rat small intestine.

In the presence of excess β-glycerophosphate or p-nitrophenylphosphate NADPH diaphorase of the epithelial cell in rat small intestine has its highest activity in the villi at the basis of the microvilli, where smooth endoplasmic reticulum of the cells is present. In the absence of β-glycerophosphate or p-nitrophenylphosphate the diaphorase activity is much higher and broader localized in crypts and villi. The increased activity is due to the conversion of NADPH to NADH by non-specific (mostly alkaline-) phosphatase activity, so that both NADPH and NADH diaphorase activities are measured. When NADPH is generated by a specific NADP+-linked dehydrogenase, such as glucose-6-phosphate dehydrogenase, and nitroblue tetrazolium is present to trap the reducing equivalents formed, the histochemical localization of the dehydrogenase is identical to that of NADPH diaphorase, although the dehydrogenase may be present in another cell compartment (glucose-6-phosphate dehydrogenase for instance has a cytosolic distribution). Therefore the localization of a dehydrogenase may be falsely interpreted histochemically, according to the diaphorase reaction involved. A different localization may be obtained when the diaphorase reaction is circumvented by the addition of an alternative hydrogen carrier, such as phenazine methosulphate. Also in coupled dehydrogenase assays this may be observed. The hexokinase reaction, coupled to the glucose-6-phosphate dehydrogenase reaction in the presence of nitroblue tetrazolium and the absence of phenazine methosulphate, has a distribution identical to NADPH diaphorase. In the presence of phenazine methosulphate the enzyme has an almost ubiquitous distribution in the small intestinal epithelial cell. When a substrate may react both with NADP+- and NAD+-linked dehydrogenases, such as L-malate: NADP oxido-reductase (decarboxylating) and L-malate: NAD oxidoreductase respectively, the high activity of intestinal alkaline phosphatase may influence the histochemical distribution by converting part of NADP+ to NAD+. The addition of another phosphate ester, such a β-glycerophosphate or p-nitrophenylphosphate, may therefore influence the observed distribution.

The Development and Distribution of Alkaline Phosphatase Activity in the Small Intestine of the Horse

Alkaline phosphatase activity located in the intestinal brush border shows a non-uniform development pattern in the fetus. Highest levels of activity are found in the distal small intestine where mature levels are reached by the ninth month of gestation but not until birth in the more proximal sites. There is little variation in the level of enzyme activity from birth through the horse’s life. Alkaline phosphatase is present in meconium and in the large intestine, although at lower levels than in the small intestine where its function in active transport mechanisms could be expected.

Interactions of Ca, P, Zn and Alkaline Phosphatase in the Chick: I. Methodological Considerations and Preliminary Findings

Three experiments were performed in the course of developing a suitable design to study the mineral-phosphatase interaction in the young chick. Commercial and semi-purified diets of varying Ca and P content were utilized in attempts to alter the intestinal alkaline phosphatase (AP) activity. Excess Ca (2.5%) in a commercial chick starter ration caused an initial decrease in AP (after 1 to 3 days) and an elevation of the enzyme (at 10 days) compared to control (1.0% Ca). On day 10 the enzyme was positively correlated with intestinal and plasma Ca and inversely correlated with plasma Zn. A low P semi-purified diet did not alter intestinal AP compared to the same diet containing adequate P (during 6 days). There appears to be developmental alterations in the mineral-phosphatase relationships during the first two weeks of life in the chick.

Studies on Alkaline Phosphatase during Development Part I: Changes of alkaline phosphatase activity and isozyme pattern in serum, liver, bone, small intestine and kidney of rats during development

SummaryThe author tried to clarify the changes of alkaline phosphatase activity and isozyme patterns in serum, liver, bone, kidney and small intestine of rats during development and organ origins of serum alkaline phosphatase appearing along with growing.Normal 30 rats were divided into 6 groups according to age and the alkaline phosphatase activity in serum and each organ was measured respectively. Alkaline phosphatase isozymes were separated by agar gel electrophoresis and the decreasing rate of alkaline phosphatase activity was measured by heat stability test.1) Organ alkaline phosphatase activity in rats was the highest in small intestine followed by the kidney and bone, and the lowest in the liver. In the change of alkaline phosphatase activity in organs according to age, no remarkable fluctuations were noted in the small intestine and the liver. In the kidney, a transient rise was noted in group 4. In the bone, the highest value was o btained in group 1 with gradual decrease, a slight rise was noted in group 5 and the lowest value in group 6.2) Serum alkaline phosphatase activity in rats was 2 to 3 times higher than that in human. The higher activity was noted in group 1 and 5, and the lowest in group 6.3) In alkaline phosphatase isozyme patterns in organs, the liver showed 2 bands and the other one band, and these isozymes showed different electrophoretic migration rates respectivery. The alkaline phosphatase isozyme pattern of liver consisted of two bands (L‐Ap1 & L‐Ap2), and showed characteristic changes during development.4) The isozyme pattern of serum consisted of two bands (S‐Ap1 & S‐Ap2)showed unique change during development.5) Heat stability test of serum and the organ alkaline phosphatase revealed that the order of the stability was as follows; L‐Ap1 in the liver, the small intestine alkaline phosphatase, the kidney alkaline phosphatase, S‐Ap2 in serum, the bone alkaline phosphatase, S‐Ap2 in serum, and L‐Ap2 in liver.6) These findings suggested that S‐Ap1 in the serum was originated from the bone, and S‐Ap2 in the serum was the mixture of small intestinal alkaline phosphatase and L‐Ap2 of the liver. To sum up, the serum alkaline phosphatase of the rats in young age appeared to originated from bone and in the relatively old age group, other serum alkaline phosphatase originating from small intestine and or liver appeared to be added.

Alkaline phosphatase and leucyl naphthylamidase activities of non-human primate small intestine

1. 1. The highest concentrations of alkaline phosphatase activity in the T. glis, C. apella, S. sciwea, P. potto, O. oedipus, and T. Nigricollis were in the duodenum or proximal jejunum. The N. coucang, M. mulatto, and P. Cynocephalus had somewhat uniform alkaline phosphatase activity along the jejunum and proximal ileum, while the A. Trivirgatus had peak levels in the proximal ileum. From 14 to 31 per cent of the intestinal alkaline phosphatase activity was inactivated by heating at 56° C. for 10 minutes. 2. 2. Leucyl naphthylamidase was highest in the jejunum of the P. potto and T. nigricollis, and in the ileum of the T. glis, N. coucang, C. apella, A. trivirgatus, and M. mulatto. Concentrations were rather uniform along the intestine of the O. oedipus, S. sciwea, and P. cynocephalus.

Phosphate absorption and alkaline phosphatase activity in the small intestine of the adult mouse and of the chick embryo and hatched chick

1. 1. When rings of mouse intestine are incubated with β-glycerophosphate, the amount of phosphate absorbed into the tissue is proportional to the alkaline phosphatase activity. More phosphate is taken up by duodenal rings, which have high phosphatase activity, than by jejunal rings, which have lower activity. Phosphate uptake is inhibited when enzyme activity is inhibited by beryllium or l-phenylalanine. 2. 2. In intestinal fragments from chick embryos and young chicks from 2 days before hatching until 2 days after, the amount of phosphate absorbed from β-glycerophosphate rises in proportion to the increase in phosphatase activity. 3. 3. When chick or mouse intestine is incubated with NaH 2PO 4, the amount of phosphate absorbed also varies in parallel with alkaline phosphatase activity.

L-homoarginine, a specific inhibitor of liver-type alkaline phosphatase, applied to the recognition of liver-type enzyme activity in rat intestine.

l-Homoarginine, an inhibitor of alkaline phosphatase, has been applied for the study of the localization of alkaline phosphatase activity in rat liver and intestine. Five substrates were employed: Na α-naphthyl acid phosphate, naphthol AS-BI phosphate, Na β-glycerophosphate, o-carboxyphenylphosphate and O-ethanolamine phosphate. Diazonium coupling was employed with the naphthol substrates; the Gomori calcium-cobalt method was used with the others. Each substrate was also employed in the presence of 12.5 mMl-phenylalanine, an intestinal (brush border-specific) alkaline phosphatase inhibitor. The liver-type enzyme, in both the liver parenchyma and the lamina propria of the small intestine, was sensitive to 12.5 mMl-homoarginine in varying degrees, depending on the substrate used. With Na α-naphthyl acid phosphate, a total inhibition was observed histochemically; l-homoarginine inhibited partially purified liver alkaline phosphatase by 97%, as measured biochemically. The alkaline phosphatase of leukocytes and macrophages of the intestinal lamina propria was inhibited in the presence of l-homoarginine but not of l-phenylalanine. Reactive elements that resembled the macrophages of the lamina propria were present in the liver. The activity in these cells was also inhibited by l-homoarginine.

Phytase and alkaline phosphatase activities in intestinal mucosae of rat, chicken, calf, and man

Phytate hydrolysis (phytase ( meso-inositol-hexaphosphate phosphohydrolase, EC 3.1.3.8)) activity was demonstrated in the extracts of the mucosae of the small intestine of the rat, chicken, calf, and man. The four species differed markedly in pH-phytase activity profiles and these in turn differed from those of the intestinal alkaline phosphatases (orthophosphoric monoester phosphohydrolase, EC 3.1.3.1) measured by release of phosphate from p-nitrophenyl phosphate or 3-glycerophosphate. Partial separation of phytase from phosphatase activities was accomplished in the course of purification of the enzymes by treatment with n-butanol and (NH 4) 2 SO 4, followed by chromatography on DEAE-cellulose. Differences in substrate-activity relationships, and inhibition by l-phenylalanine and NaF provided additional support for the hydrolysis of phytate as an activity distinct from that promoting hydrolysis of p-nitrophenyl or 3-glycerophosphates. Evidence to the contrary based on assays of the two activities in the presence of mixture of their substrates is invalidated by the finding that sodium phytate inhibits intestinal alkaline phosphatase activity. Treatment of phytase concentrates with EDTA lowers their activity significantly. Alkaline phosphatase is affected in a similar manner. Partial restoration in chicken and enhancement in rat preparations of both activities follows addition of Zn 2+. Higher concentrations of Zn 2+ inhibit, although at different levels.

Effect of vitamin D on brush border alkaline phosphatase in the rat small intestine.

Intestinal brush border alkaline phosphatase activity was measured by histochemical and biochemical methods at different locations along the rat small intestine to examine the enzymatic response to vitamin D. The administration of vitamin D to rachitic rats increased enzyme activity in the duodenum but not in jejunum or ileum.