Sex steroid modulation of the hepatic uptake of organic anions in rat

1988 ◽  
Vol 6 (3) ◽  
pp. 343-349 ◽  
Author(s):  
Marcello Persico ◽  
Stefano Bellentani ◽  
Patrizia Marchegiano ◽  
Nicoletta Orzes ◽  
Gian Carlo Lunazzi ◽  
...  
Keyword(s):  
Hepatic Uptake ◽  
Organic Anions ◽  
Sex Steroid ◽  
Steroid Modulation

On the design and interpretation of experiments to elucidate albumin-dependent hepatic uptake

1992 ◽  
Vol 262 (6) ◽  
pp. G1127-G1137 ◽  
Author(s):  
Z. S. Cai ◽  
F. J. Burczynski ◽  
B. A. Luxon ◽  
E. L. Forker
Keyword(s):  
Cell Surface ◽  
Mathematical Models ◽  
Driving Force ◽  
Free Ligand ◽  
Hepatic Uptake ◽  
Organic Anions ◽  
Putative Mechanism

The liver's apparently anomalous extraction of organic anions tightly bound to albumin continues to provoke controversy and confusion. Decisive experiments have proved difficult to design, and mathematical models have usually been constructed to defend one or another putative mechanism to the exclusion of others. To stimulate more decisive experiments and as an aid to interpreting those already reported, we discuss a general formulation of the problem that predicts the clearance pattern to be expected when facilitated dissociation and codiffusion are joint determinants of the uptake flux. The results provide an approach to modeling the various mechanisms by which the concentration of bound ligand at the cell surface could be a driving force for uptake. Further we present new calculations to clarify the interpretation of net ligand clearance when the removal of free ligand is the result of bidirectional fluxes into and out of an unstirred sink. Applied to a previously published comparison of the uptake performances of hepatocytes and polyethylene, the new calculations support the inference that facilitated dissociation of albumin-palmitate complexes occurs at or near the hepatocyte surface.

A membrane-bound form of protein disulfide isomerase (PDI) and the hepatic uptake of organic anions

1993 ◽  
Vol 1153 (2) ◽  
pp. 175-183 ◽  
Author(s):  
Walther Honscha ◽  
Mazen Ottallah ◽  
Andrea Kistner ◽  
Heike Platte ◽  
Ernst Petzinger
Keyword(s):  
Protein Disulfide Isomerase ◽  
Hepatic Uptake ◽  
Organic Anions ◽  
Disulfide Isomerase ◽  
Membrane Bound ◽  
Protein Disulfide

Sex steroid modulation of signal transduction in thymus epithelial cell culture

1998 ◽  
Vol 4 (4) ◽  
pp. 281-288
Author(s):  
Wei He ◽  
Kou Sakabe ◽  
Masahiko Okuma ◽  
Tsunetoshi Itoh ◽  
Kanji Seiki
Keyword(s):  
Signal Transduction ◽  
Cell Culture ◽  
Epithelial Cell ◽  
Sex Steroid ◽  
Epithelial Cell Culture ◽  
Steroid Modulation

Processing of cholecystokinin by isolated liver cells

1989 ◽  
Vol 257 (2) ◽  
pp. G242-G248 ◽  
Author(s):  
G. J. Gores ◽  
L. J. Kost ◽  
L. J. Miller ◽  
N. F. LaRusso
Keyword(s):  
Liver Cell ◽  
Cyclic Peptides ◽  
Rat Hepatocytes ◽  
Hepatic Uptake ◽  
Organic Anions ◽  
Disulfonic Acid ◽  
Isolated Perfused Rat Liver ◽  
Dependent Manner ◽  
Temperature Dependent ◽  
Significant Uptake

Although hepatic uptake of cholecystokinin (CCK) has been demonstrated, the liver cell involved and the mechanism of uptake remain unclear. We have used dispersed rat hepatocytes, Kupffer cells, and hepatic endothelial cells to characterize uptake and metabolism of radiolabeled CCK peptides. Only rat hepatocytes showed significant uptake of 125I-labeled cholecystokinin octapeptide (125I-CCK-8). Peptide specificity of uptake by hepatocytes was similar to that seen in the isolated perfused rat liver, with extraction of 125I-CCK-8 being sevenfold greater than that of 125I-CCK-33. Uptake was saturable, as 10(-4) M CCK-4 inhibited uptake of 125I-CCK-8 by 85%. Uptake was rapid, temperature dependent, and extensive and was decreased by metabolic inhibition, a proteolytic enzyme (trypsin), organic anions (sulfobromophthalein and taurocholic acid), and an inhibitor of anion transport 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid. In addition, uptake was dependent on extracellular anions but not on extracellular sodium, calcium, or magnesium. After uptake, hepatocytes released radiolabel in a time- and temperature-dependent manner, predominantly in metabolized forms. Thus the hepatocyte is the liver cell that extracts CCK by an active, anion-dependent process. The characteristics of the uptake process resemble those described for organic anions and small, cyclic peptides and suggest that small, linear peptides may undergo hepatocyte extraction by a similar mechanism.

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