No evidence for a tumor necrosis factor alpha stimulated 2-methylaminoisobutyric acid uptake in hepatocyte monolayer.
This study investigates the short-term effects of glucagon and human recombinant tumor necrosis factor alpha (TNF alpha) singly and in association on 2-methylaminoisobutyric acid (MeAIB) transport in hepatocyte monolayers. As expected, glucagon induced a time-dependent stimulation of MeAIB transport. In our experimental conditions, TNF alpha did not induce cytolysis. A 2 hour exposure to TNF alpha (0.05-500 ng/l) with or without glucagon (10(-9) to 10(-6) M) did not modify the basal or glucagon-stimulated MeAIB transport. Varying the duration of exposure to TNF alpha 5 ng/l up to 6 h was equally ineffective. The presence of hydrocortisone potentiated the glucagon-stimulated transport, but TNF alpha remained ineffective. Finally, the association of interferon (IFN gamma) with TNF alpha and/or glucagon was unable to modify the transport activity. These data demonstrate that TNF alpha does not exert a direct effect on MeAIB transport in hepatocytes, at least on a short-term basis.
Laboratoire de Biochimie A, Hôpital Saint-Antoine, Paris, France.
S K
SK
Lim
J P
JP
De Bandt
C
C
Aussel
P
P
Pernet
J
J
Giboudeau
L
L
Cynober
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002478:Cells, Cultured; D005934:Glucagon / Q000494:pharmacology; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000494:pharmacology; D008099:Liver / Q000378:metabolism*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012709:Serum Albumin / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D015091:beta-Alanine / Q000031:analogs & derivatives* / Q000378:metabolism
D012709:Serum Albumin; D014409:Tumor Necrosis Factor-alpha; D015091:beta-Alanine; C012924:2,2-dimethyl-beta-alanine; D007371:Interferon-gamma; D005934:Glucagon