Metabolic and secretory responses of parotid cells to cationic amino acids. Oxidation of the amino acids and interference with the oxidation of D-glucose or endogenous nutrients.
Cationic amino acids were recently found to stimulate amylase release from rat parotid cells. The possible relevance of their oxidative catabolism to such a secretory stimulation was investigated. D-Glucose, which was efficiently metabolized in parotid cells and which augmented O2 uptake above basal value, failed to affect basal or stimulated amylase release. L-Arginine, L-lysine and L-histidine failed to stimulate the oxidation of either exogenous D-[6-14C]glucose or endogenous nutrients in cells pre-labelled with [U-14C]palmitate or L-[U-14C]glutamine. The oxidation of L-[U-14C]arginine, L-[U-14C]ornithine, L-[U-14C]lysine and L-[U-14C]histidine, all tested at a 10 mM concentration, was much lower than that of D-[U-14C]glucose (5.6 mM). These findings argue against the view that the stimulation of amylase release by cationic amino acids would be related to their role as a source of energy in the parotid cells.
Sener
A
A
Laboratory of Experimental Medicine, Brussels Free University, Belgium.
Mourtada
A
A
Blachier
F
F
Malaisse
W J
WJ
D000681:Amylases / Q000378:metabolism; D000818:Animals; D005260:Female; D005947:Glucose / Q000378:metabolism*; D007700:Kinetics; D010100:Oxygen / Q000378:metabolism; D010306:Parotid Gland / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D051381:Rats; D014501:Uranium
D014501:Uranium; D000681:Amylases; D005947:Glucose; D010100:Oxygen