PAH transport in rock crab urinary bladder. II. Luminal and serosal steps

1982 ◽  
Vol 242 (1) ◽  
pp. R25-R29
Author(s):  
C. W. Holliday ◽  
D. S. Miller
Keyword(s):  
Urinary Bladder ◽  
Transport Properties ◽  
Organic Anion ◽  
Ringer Solution ◽  
Anion Transport ◽  
Bromocresol Green ◽  
Organic Anion Transport ◽  
High Affinity ◽  
Luminal Membrane ◽  
Rock Crab

To characterize the organic anion transport properties of the luminal (1) and serosal (s) membranes of crab urinary bladder, initial (10 min) fluxes (J) and tissue accumulations (Ac) of 10 microM PAH were measured in the absence and presence of 1 mM BCG (nontransported, high-affinity competitor). Control bladders exhibited net reabsorptive transport with a mean Jl leads to s/Js leads to 1 of about 7; concentrative transport of p-aminohippuric acid (PAH) occurred only across the luminal cell (c) membrane. With luminal PAH, luminal bromocresol green (BCG) reduced Jl leads to c, Jc leads to s, and Ac by about 85%; serosal BCG reduced Jc leads to s, increased Ac but had no effect on Jl leads to c. With serosal PAH, serosal BCG reduced Js leads to c, Jc leads to l, and Ac; luminal BCG had no effects on either fluxes or tissue accumulation. When bladder sheets were loaded with radiolabeled PAH, mounted in a chamber, and exposed to flowing crab Ringer solution on both sides, Jc leads to s was nearly twice as large as Jc leads to l; BCG significantly reduced Jc leads to s but not Jc leads to l. With unlabeled PAH in the efflux media, Jc leads to s was increased. The data are consistent with a model featuring an inwardly directed pump at the luminal membrane, a facilitated carrier at the serosal membrane, and nonmediated pathways at both membranes.

PAH transport in rock crab (Cancer irroratus) urinary bladder

1980 ◽  
Vol 238 (5) ◽  
pp. R311-R317
Author(s):  
C. W. Holliday ◽  
D. S. Miller
Keyword(s):  
Urinary Bladder ◽  
Initial Section ◽  
Bromocresol Green ◽  
Double Reciprocal Plot ◽  
Flux Chamber ◽  
Cancer Irroratus ◽  
Chlorophenol Red ◽  
Luminal Membrane ◽  
Saturation Kinetics ◽  
Rock Crab

Crab urinary bladder appears to possess several morphological and functional similarities to vertebrate renal proximal tubule. Sections of intermolt rock crab bladder accumulated PAH by a process that was concentrative (60 min tissue-to-medium ratio (T/M) for 10 microM PAH averaged 24), Na dependent, powered by glycolytic metabolism, and inhibitable by other organic anions. Initial section uptakes exhibited saturation kinetics and a double-reciprocal plot of uptake vs. concentration yielded a single line with a Km of 70 microM and a Vmax of 5 nmol . mg tissue-1 . h-1. Chlorophenol red and bromocresol green (BCG) competitively inhibited PAH uptake. When bladder sheets were mounted in a flux chamber, they exhibited a large, net lumen-to-serosa (L leads to S) flux of 10 microM PAH that was abolished by 1 mM BCG. The small unidirectional S leads to L flux was not BCG-inhibitable. Bladder sheets exhibited PAH T/M greater than 1 after luminal, but not serosal, exposure. BCG only reduced bladder sheet T/M after luminal exposure. The data are consistent with uphill, Na-dependent, and carrier-mediated entry of PAH at the luminal membrane and nonmediated exit at the serosal membrane.

Organic anion transport in HepG2 cells: Absence of the high-affinity, chloride-dependent transporter

Hepatology ◽  
1991 ◽  
Vol 14 (6) ◽  
pp. 1217-1223 ◽  
Author(s):  
Albert D. Min ◽  
Tobias Goeser ◽  
Rui Liu ◽  
Celeste G. Campbell ◽  
Phyllis M. Novikoff ◽  
...  
Keyword(s):  
Hepg2 Cells ◽  
Organic Anion ◽  
Anion Transport ◽  
Organic Anion Transport ◽  
High Affinity

PAH secretion in the urinary bladder of a crab Cancer borealis

1982 ◽  
Vol 243 (1) ◽  
pp. R147-R151
Author(s):  
D. S. Miller ◽  
C. W. Holliday
Keyword(s):  
Urinary Bladder ◽  
Organic Anion ◽  
Bromocresol Green ◽  
Glycolytic Metabolism ◽  
Flux Chamber ◽  
Cancer Borealis ◽  
Cellular Accumulation ◽  
Luminal Membrane ◽  
Secretory Transport ◽  
Chamber Studies

Uptake of 10 microM p-aminohippuric acid (PAH) by sections of Cancer borealis urinary bladder was concentrative, saturable (Km 67 microM, Vmax 1.7 nmol.mg tissue-1.h-1), inhibitable by other organic anions, and dependent on medium Na and glycolytic metabolism. Bladders mounted in flux chambers exhibited net secretory transport of PAH, with serosa-to-lumen fluxes (Js leads to l) being about 4 times lumen-to-serosa fluxes (Jl leads to s). In 60-min flux chamber studies, tissue-to-medium ratios exceeded unity with serosal, but not luminal, PAH. Initial (10 min) fluxes and tissue accumulations (Ac) were measured in the absence and presence of 1-5 mM BCG (bromocresol green; competitor organic anion). With serosal PAH, serosal BCG (1 mM) reduced serosa-to cell flux (Js leads to c), Ac, and Jc leads to l by 60-75%. With luminal PAH, luminal BCG (1 mM) had no effect on Jl leads to c, Ac, or Jc leads to s; increasing the luminal BCG concentration to 5 mM reduced Jl leads to c, Ac, and Jc leads to s by 40-50%. The data are consistent with a model featuring an inwardly directed pump on the serosal membrane, cellular accumulation, and a facilitated carrier on the luminal membrane.

scholarly journals Characteristics of bile salt uptake into skate hepatocytes

1994 ◽  
Vol 299 (3) ◽  
pp. 665-670 ◽  
Author(s):  
G Fricker ◽  
V Dubost ◽  
K Finsterwald ◽  
J L Boyer
Keyword(s):  
Substrate Specificity ◽  
Bile Salt ◽  
Transport System ◽  
Bile Salts ◽  
Organic Anion ◽  
Anion Transport ◽  
Organic Anion Transport ◽  
Salt Uptake ◽  
Anion Transport System ◽  
Alpha 7

The substrate specificity for the transporter that mediates the hepatic uptake of organic anions in freshly isolated hepatocytes of the elasmobranch little skate (Raja erinacea) was determined for bile salts and bile alcohols. The Na(+)-independent transport system exhibits a substrate specificity, which is different from the specificity of Na(+)-dependent bile salt transport in mammals. Unconjugated and conjugated di- and tri-hydroxylated bile salts inhibit uptake of cholyltaurine and cholate competitively. Inhibition is significantly greater with unconjugated as opposed to glycine- or taurine-conjugated bile salts. However, the number of hydroxyl groups in the steroid moiety of the bile salts has only minor influences on the inhibition by the unconjugated bile salts. Since the transport system seems to represent an archaic organic-anion transport system, other anions, such as dicarboxylates, amino acids and sulphate, were also tested, but had no inhibitory effect on bile salt uptake. To clarify whether bile alcohols, the physiological solutes in skate bile, share this transport system, cholyltaurine transport was studied after addition of 5 beta-cholestane-3 beta,5 alpha,6 beta-triol, 5 alpha-cholestan-3 beta-ol and 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha-triol. These bile alcohols inhibit cholyltaurine uptake non-competitively. In contrast, uptake of 5 beta-cholestane-3 alpha,7 alpha,12 alpha-triol, which is Na(+)-independent, is not inhibited by cholyltaurine. The findings further characterize a Na(+)-independent organic-anion transport system in skate liver cells, which is not shared by bile alcohols and has preference for unconjugated lipophilic bile salts.

scholarly journals Hepatocanalicular organic-anion transport is regulated by protein kinase C

1991 ◽  
Vol 278 (3) ◽  
pp. 637-641 ◽  
Author(s):  
H Roelofsen ◽  
R Ottenhoff ◽  
R P J Oude Elferink ◽  
P L M Jansen
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Organic Anion ◽  
Phosphodiesterase Inhibitor ◽  
Second Messenger ◽  
Anion Transport ◽  
Organic Anion Transport ◽  
Kinase C ◽  
Transport Assay ◽  
Messenger System

In order to investigate the regulation of canalicular organic-anion transport, we used a hepatocyte transport assay in which canalicular secretion of a model organic anion, dinitrophenyl-glutathione (GS-DNP), was measured in the presence of stimulators and inhibitors of the Ca2+/protein kinase C (PKC) second-messenger system and of the cyclic AMP (cAMP) second-messenger system. Vasopressin (24 nM) and the phorbol ester phorbol 12-myristate 13-acetate (1 microgram/ml), both stimulators of PKC, stimulated GS-DNP efflux by 65 +/- 36% and 55 +/- 28% respectively, whereas staurosporine (10 microM), an inhibitor of PKC, inhibited efflux by 53 +/- 13%. Glucagon and forskolin, both stimulators of the cAMP second-messenger system, as well as the cAMP analogue dibutyryl cAMP and the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine, did not significantly influence the GS-DNP efflux. It can be concluded that canalicular organic-anion transport in hepatocytes is either directly or indirectly regulated by PKC.

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