Effect of hyper or hypo-osmotic conditions on neutral amino acid uptake and oxidation in tissues of the crab Chasmagnathus granulata

• Published in: Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology Vol. 140; no. 4; pp. 561 - 567
• Main Authors: Schein, Vanessa, Fernandes Chittó, Ana Lúcia, Etges, Rodrigo, Kucharski, Luiz Carlos, van Wormhoudt, Alain, Da Silva, Roselis S.M.
• Format: Journal Article
• Language: English
• Published: England Elsevier Inc 01-04-2005
• Subjects: Alanine - chemistry; Alanine - metabolism; Amino acid uptake and oxidation; Amino Acids - chemistry; Amino Acids - metabolism; Animals; beta-Alanine - analogs & derivatives; beta-Alanine - chemistry; beta-Alanine - metabolism; Brachyura - chemistry; Brachyura - metabolism; Carbon Dioxide - metabolism; Carbon Isotopes; Hepatopancreas; Hepatopancreas - chemistry; Hepatopancreas - metabolism; Jaw - chemistry; Jaw - metabolism; Jaw muscle; Marine; Muscles - chemistry; Muscles - metabolism; Osmotic Pressure; Osmotic stress; Oxidation-Reduction; Time Factors; Jaw muscle; Hepatopancreas; Amino acid uptake and oxidation; Osmotic stress
• ISSN: 1096-4959; 1879-1107
• DOI: 10.1016/j.cbpc.2004.12.002

We investigated the transport of
14C-methylaminoisobutyric acid (
14C-MeAIB) and
14C-alanine oxidation in hepatopancreas and jaw muscle of
Chasmagnathus granulata submitted to 24, 72, and 144 h of hypo- or hyperosmotic stress. While
14C-MeAIB uptake increased in jaw muscle and hepatopancreas from crabs submitted to hyperosmotic stress, it did not change in tissues from animals submitted to hypo-osmotic stress. Incubation of jaw muscle and hepatopancreas from control groups with 1 mM ouabain did not decrease
14C-MeAIB uptake. However, ouabain prevented
14C-MeAIB uptake in hepatopancreas at 24 h of hyperosmotic stress. In contrast, in jaw muscle from crabs submitted to the same conditions,
14C-MeAIB uptake was not prevented by ouabain in the incubation medium. Jaw muscle from the control group produced four times more
14CO
2 from
14C-alanine than the hepatopancreas. During hypo-osmotic stress, amino acid oxidation does not seem to be one of the pathways implicated in the decrease of the amino acid pools in hepatopancreas and jaw muscle. In contrast, during hyperosmotic stress the reduction in
14C-alanine oxidation appears to be one of the mechanisms involved in the increase of the amino acid pool in the hepatopancreas.