Ca2+ inhibition of brush border alkaline phosphatase activity inHymenolepis diminuta

1985 ◽  
Vol 71 (6) ◽  
pp. 759-763 ◽  
Author(s):  
Jayne B. Hipkiss ◽  
Christopher J. Branford White
Keyword(s):  
Alkaline Phosphatase ◽  
Phosphatase Activity ◽  
Alkaline Phosphatase Activity ◽  
Brush Border

Presence of γ-glutamyltransferase in the renal microvascular compartment

1981 ◽  
Vol 59 (6) ◽  
pp. 383-386 ◽  
Author(s):  
P. D. Dass ◽  
R. P. Misra ◽  
T. C. Welbourne
Keyword(s):  
Alkaline Phosphatase ◽  
Phosphatase Activity ◽  
Density Gradient ◽  
Alkaline Phosphatase Activity ◽  
Brush Border ◽  
Sucrose Density Gradient ◽  
Isolated Glomeruli ◽  
Crude Homogenate ◽  
Brush Border Enzyme ◽  
Enzyme Alkaline Phosphatase

The association between the brush border enzyme alkaline phosphatase and γ-glutamyltransferase was determined by sucrose density gradient analysis of crude kidney homogenates, isolated glomeruli, and isolated microvessels. As previously established there is an overlap of these enzyme activities in the crude homogenate corresponding to a density of 1.17 g∙cm−3. In contrast, isolated glomeruli sedimented with a peak of 1.25 g∙cm−3 and exhibited γ-glutamyltransferase activity but little alkaline phosphatase activity; homogenizing isolated glomeruli shifted the fragments to a density coincident with that observed for the crude homogenate γ-glutamyltransferase peak. A second population of capillaries, isolated microvessels, were homogenized and analyzed on the sucrose density gradient. These fragments sedimented over the same range as crude homogenate γ-glutamyltransferase peak but were devoid of alkaline phosphatase activity and yet exhibited remarkable γ-glutamyltransferase activity. The results indicate homogenization of renal cortex results in a heterogenous collection of particles from both tubular and microvascular locations exhibiting γ-glutamyltransferase activity which overlap with the brush border alkaline phosphatase containing membranes. However, isolation of microvessels and glomeruli prior to homogenization allows separation of γ-glutamyltransferase from alkaline phosphatase activity; between 10 and 20% of the total homogenate γ-glutamyltransferase activity is estimated to be associated with the microvascular compartment.

scholarly journals Alkaline phosphatase activity does not mediate phosphate transport in the renal-cortical brush-border membrane

1980 ◽  
Vol 190 (2) ◽  
pp. 473-476 ◽  
Author(s):  
H S Tenenhouse ◽  
C R Scriver ◽  
E J Vizel
Keyword(s):  
Alkaline Phosphatase ◽  
Phosphatase Activity ◽  
Alkaline Phosphatase Activity ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Phosphate Transport ◽  
Mouse Kidney ◽  
Brush Border Membrane Vesicles ◽  
Low Phosphorus

We studied (1) the effect of primary modulators of phosphate transport, namely the hypophosphataemic mouse mutant (Hyp) and low-phosphorus diet, on alkaline phosphatase activity in mouse renal-cortex brush-border membrane vesicles and (2) the effect of several primary inhibitors of alkaline phosphatase on phosphate transport. Brush-border membrane vesicles from Hyp-mouse kidney had 50% loss of Na+-dependent phosphate transport, but only 18% decrease in alkaline phosphatase activity. The low-phosphorus diet effectively stimulated Na+/phosphate co-transport in brush-border membrane vesicles (+ 118%), but increased alkaline phosphatase activity only slightly (+13%). Levamisole (0.1 mM) and EDTA (1.0 mM) inhibited brush-border membrane-vesicle alkaline phosphatase activity of 82% and 93% respectively, but had no significant effect on Na+/phosphate co-transport. We conclude that alkaline phosphatase does not play a direct role in phosphate transport across the brush-border membrane of mouse kidney.

The dependence of duodenal differentiation in chick embryos on pars distalis hormones

Development ◽  
1970 ◽  
Vol 24 (2) ◽  
pp. 335-355
Author(s):  
F. T. Bellware ◽  
T. W. Betz
Keyword(s):  
Alkaline Phosphatase ◽  
Phosphatase Activity ◽  
Alkaline Phosphatase Activity ◽  
Brush Border ◽  
Dry Weight ◽  
Chick Embryos ◽  
Pars Distalis ◽  
Mucosal Cells ◽  
Mitotic Figures ◽  
Cytoplasmic Glycogen

Duodenal differentiation in normal chick embryos between 15·75 and 20·5 days of incubation was characterized by the following changes: 1. The dry weight increases from 4·1 to 12·4 mg. 2. The alkaline phosphatase activity increases from less than 12 to 426 units. 3. The length of the villi increases sixfold. 4. The height of the epithelial cells at the villous tips increases from 12·9 to 25·9 μ. 5. The shape of the mucosal cells changes from low columnar, to cuboidal, to high columnar. 6. The shape of the nuclei progresses from round to ovoid. 7. At first mitotic figures are distributed throughout the epithelium but become restricted to the crypts of Lieberkühn. 8. Cytoplasmic glycogen appears by day 15·75 and is mobilized by 20·5 days. 9. A mucopolysaccharide at the brush border of the mucosal cells progressively appears at 16·75 days and increases in amount. 10. Alkaline phosphatase activity (Gomori technique) at the brush border appears in low levels at 16·75 days and becomes more intense. 11. Fresh body weights and third toe lengths at 19·75 and 20·5 days of incubation were recorded as indices of body growth. In ‘hypophysectomized’ embryos at 19·75–21·5 days of age: 12. The level of duodenal differentiation approximated that of normal 16·75–17·75 day embryos. 13. In ‘phypophysectomized’ embryos which received a pars distalis chorioallantoic homograft at 9·5 days of incubation the duodena were normal. 14. In ‘hypophysectomized’ embryos with grafts which became atrophic the level of duodenal differentiation was not different from that of untreated ‘hypophysectomized’ embryos. 15. In chick embryos duodenal differentiation depends on pars distalis hormones.

A Histochemical Basis for Changes in Rental Tubular Function in Young Mice

1956 ◽  
Vol s3-97 (38) ◽  
pp. 187-195
Author(s):  
JAMES B. LONGLEY ◽  
EDWIN R. FISHER
Keyword(s):  
Alkaline Phosphatase ◽  
Proximal Tubule ◽  
Phosphatase Activity ◽  
Alkaline Phosphatase Activity ◽  
Brush Border ◽  
Morphological Changes ◽  
Periodic Acid ◽  
Periodic Acid Schiff ◽  
Pas Reaction ◽  
Young Mice

In the kidney of the adult mouse the tubular epithelium in the most proximal (Pr) segment, corresponding roughly to the convoluted portion of the proximal tubule, shows strong alkaline phosphatase activity, and the brush border is moderately reactive to the periodic acid Schiff (PAS) method. In the more distal (P2) segment of the proximal tubule there is no alkaline phosphatase activity, and the PAS reaction of the brush border is intense. Examination of a large number of young mice has now revealed a distinct pattern in the development of this adult condition. Differentiation of the two segments on the basis of the PAS reaction of the brush border becomes apparent on about the 15th post-natal day. The effect is the result of a decrease in the reactivity of the Pi segment. Differentiation of the two segments on the basis of alkaline phosphatase activity develops gradually between about the 22nd and 36th post-natal days. During this period the alkaline phosphatase activity disappears progressively from the proximal to the distal end of the P2 segment. The administration of testosterone or estradiol to either sex accelerates the differentiation with respect to alkaline phosphatase activity. Castration of male mice retards the completion of this process. It is suggested that morphological changes of this type may provide the basis for some of the functional differences between the kidneys of young and mature animals.

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