scholarly journals Sulphonylureas in vitro do not alter insulin binding or insulin effect on amino acid transport in rat hepatocytes

Diabetologia ◽  
1983 ◽  
Vol 24 (6) ◽  
Author(s):  
J. Dolais-Kitabgi ◽  
F. Alengrin ◽  
P. Freychet
Keyword(s):  
Amino Acid ◽  
Amino Acid Transport ◽  
Rat Hepatocytes ◽  
Insulin Binding ◽  
Acid Transport ◽  
Insulin Effect

scholarly journals Glucagon resistance of hepatoma cells. Evidence for receptor and post-receptor defects

1983 ◽  
Vol 214 (3) ◽  
pp. 845-850 ◽  
Author(s):  
M Fehlmann ◽  
M Crettaz ◽  
C R Kahn
Keyword(s):  
Amino Acid ◽  
Cyclic Amp ◽  
Amino Acid Transport ◽  
Hepatoma Cell ◽  
Insulin Binding ◽  
Hepatoma Cells ◽  
Hepatoma Cell Line ◽  
Acid Transport ◽  
Dibutyryl Cyclic Amp

Of all available liver cells in culture, only primary cultured hepatocytes are known to respond to glucagon in vitro. In the present study we investigated whether glucagon could stimulate amino acid transport and tyrosine aminotransferase (TAT;EC 2.6.1.5) activity (two well-characterized glucagon effects in the liver) in Fao cells, a highly differentiated rat hepatoma cell line. We found that glucagon had no effect on transport of alpha-aminoisobutyric acid (AIB; a non-metabolizable alanine analogue) nor on TAT activity, even though both activities could be fully induced by insulin [2-fold and 3-fold effects for AIB transport and TAT activity, respectively, after 6h; EC50 (median effective concentration) = 0.3 nM], or by dexamethasone (5-8-fold effects after 20 h; EC50 = 2 nM). Analysis of [125I]iodoglucagon binding revealed that Fao cells bind less than 1% as much glucagon as do hepatocytes, whereas insulin binding in Fao cells was 50% higher than in hepatocytes. The addition of dibutyryl cyclic AMP, which fully mimics the glucagon stimulation of both AIB transport and TAT activity in hepatocytes, induced TAT activity in Fao cells (a 2-fold effect at 0.1 mM-dibutyryl cyclic AMP) but had no effect on AIB transport. Cholera toxin stimulated TAT activity to the same extent as did dibutyryl cyclic AMP. These results indicate that the lack of glucagon responsiveness in cultured hepatoma cells results from both a receptor defect and, for amino acid transport, an additional post-receptor defect. Moreover, the results show that amino acid transport and TAT activity, which appeared to be co-induced by insulin or by dexamethasone in these cells, respond differently to cyclic AMP. This suggests that different mechanisms are involved in the induction of these activities by glucagon in liver.

Interaction between growth hormone and rat muscle in vitro

1961 ◽  
Vol 200 (4) ◽  
pp. 675-678 ◽  
Author(s):  
J. L. Kostyo ◽  
J. E. Schmidt
Keyword(s):  
Growth Hormone ◽  
Amino Acid ◽  
Amino Acid Transport ◽  
Growth Hormones ◽  
Hormone Concentration ◽  
Acid Transport ◽  
Rat Muscle ◽  
Resultant Effect ◽  
Initial Interaction

Hypophysectomized rat diaphragms, which were immersed briefly in dilute solutions of growth hormone and then washed thoroughly, subsequently transported α-aminoisobutyric acid-1-C14 at a greater rate than the controls. Growth hormones of bovine, porcine, simian and human origins were all effective. Increasing either the hormone concentration or the length of time that the diaphragms were immersed in growth hormone solutions increased the effect on amino acid transport. Prolonged washing of the diaphragms following exposure to growth hormone did not reduce the magnitude of the effect on amino acid transport. Moreover, reducing the temperature of the growth hormone solutions did not diminish the resultant effect on amino acid transport. From these results, it was concluded that the initial interaction between growth hormone and rat muscle in vitro occurs rapidly and the modification produced by this interaction is relatively stable.

Insulin effect on amino acid transport in bone

1969 ◽  
Vol 184 (3) ◽  
pp. 675-677 ◽  
Author(s):  
Theodore J. Hahn ◽  
Sylvia J. Downing ◽  
James M. Phang
Keyword(s):  
Amino Acid ◽  
Amino Acid Transport ◽  
Acid Transport ◽  
Insulin Effect

scholarly journals Adenosine induces system A amino acid transport in rat hepatocytes

1990 ◽  
Vol 52 ◽  
pp. 118
Author(s):  
Hiroaki Kiyokawa ◽  
Hiroyuki Fukui ◽  
Hiroyuki Mizuguchi ◽  
Akiharu Kubo ◽  
Norio Kono ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Transport ◽  
Rat Hepatocytes ◽  
Acid Transport ◽  
System A
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