Vitamin D status and brush border membrane vesicles: 1,25-dihydroxyvitamin D3 induced destabilization

2009 ◽  
Vol 1 (4) ◽  
pp. 305-311 ◽  
Author(s):  
J. A. Putkey ◽  
I. Nemere ◽  
A. W. Norman
Keyword(s):  
Vitamin D ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Brush Border Membrane Vesicles ◽  
Vitamin D Status ◽  
Dihydroxyvitamin D3 ◽  
1,25 Dihydroxyvitamin D3

Regulation of Na+-Pi cotransport by 1,25-dihydroxyvitamin D3 in rabbit duodenal brush-border membrane

1982 ◽  
Vol 242 (5) ◽  
pp. G533-G539 ◽  
Author(s):  
B. Hildmann ◽  
C. Storelli ◽  
G. Danisi ◽  
H. Murer
Keyword(s):  
Brush Border ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Brush Border Membrane Vesicles ◽  
Precipitation Method ◽  
Dihydroxyvitamin D3 ◽  
1,25 Dihydroxyvitamin D3 ◽  
Pi Transport ◽  
Sodium Dependent ◽  
Cotransport System

Brush-border membrane vesicles were isolated from rabbit duodenum by a Mg2+ precipitation method, and phosphate transport was analyzed by a rapid filtration technique. Uptake of inorganic phosphate (Pi) was stimulated by an inwardly directed sodium gradient, indicating the operation of a Na-Pi cotransport system in brush-border membrane vesicles. Treatment of the animals with ethane-1-hydroxy-1,1-diphosphonate (EHDP), which is known to decrease the circulating levels of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], reduced within 3 days the sodium-dependent Pi transport in the brush-border vesicles. Injections of 1,25(OH)2D3 into rabbits increased within 9 h the sodium-dependent Pi transport in membranes from EHDP-treated animals as well as in untreated ones. The Na-D-glucose cotransport system appeared to be unaffected by these maneuvers. These results suggest that the Na-Pi cotransport system is an important site of regulation of intestinal transepithelial Pi transport by 1,25(OH)2)D3.

Low-affinity transport of pyroglutamyl-histidine in renal brush-border membrane vesicles

1989 ◽  
Vol 257 (5) ◽  
pp. C971-C975 ◽  
Author(s):  
H. A. Skopicki ◽  
K. Fisher ◽  
D. Zikos ◽  
G. Flouret ◽  
D. R. Peterson
Keyword(s):  
Brush Border ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Brush Border Membrane Vesicles ◽  
Proximal Tubular Cells ◽  
Tubular Cells ◽  
Luminal Membrane ◽  
Renal Brush Border Membrane ◽  
Proximal Tubular ◽  
Renal Brush Border

These studies were performed to determine if a low-affinity carrier is present in the luminal membrane of proximal tubular cells for the transport of the dipeptide, pyroglutamyl-histidine (pGlu-His). We have previously described the existence of a specific, high-affinity, low-capacity [transport constant (Kt) = 9.3 X 10(-8) M, Vmax = 6.1 X 10(-12) mol.mg-1.min-1] carrier for pGlu-His in renal brush-border membrane vesicles. In the present study, we sought to demonstrate that multiple carriers exist for the transport of a single dipeptide by determining whether a low-affinity carrier also exists for the uptake of pGlu-His. Transport of pGlu-His into brush-border membrane vesicles was saturable over the concentration range of 10(-5)-10(-3) M, yielding a Kt of 6.3 X 10(-5) M and a Vmax of 2.2 X 10(-10) mol.mg-1.min-1. Uptake was inhibited by the dipeptides glycyl-proline, glycyl-sarcosine, and carnosine but not by the tripeptide pyroglutamyl-histidyl-prolinamide. We conclude that 1) pGlu-His is transported across the luminal membrane of the proximal tubule by multiple carriers and 2) the lower affinity carrier, unlike the higher affinity carrier, is nonspecific with respect to other dipeptides.

Hydrolysis and transglycosylation activities of glycosidases from small intestine brush-border membrane vesicles

2021 ◽  
Vol 139 ◽  
pp. 109940
Author(s):  
Lesbia Cristina Julio-Gonzalez ◽  
F. Javier Moreno ◽  
María Luisa Jimeno ◽  
Elisa G. Doyagüez ◽  
Agustín Olano ◽  
...  
Keyword(s):  
Small Intestine ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Brush Border Membrane Vesicles
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