Effect of hyper or hypo-osmotic conditions on neutral amino acid uptake and oxidation in tissues of the crab Chasmagnathus granulata.
We investigated the transport of (14)C-methylaminoisobutyric acid ((14)C-MeAIB) and (14)C-alanine oxidation in hepatopancreas and jaw muscle of Chasmagnathus granulata submitted to 24, 72, and 144 h of hypo- or hyperosmotic stress. While (14)C-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 (14)C-MeAIB uptake. However, ouabain prevented (14)C-MeAIB uptake in hepatopancreas at 24 h of hyperosmotic stress. In contrast, in jaw muscle from crabs submitted to the same conditions, (14)C-MeAIB uptake was not prevented by ouabain in the incubation medium. Jaw muscle from the control group produced four times more (14)CO(2) from (14)C-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 (14)C-alanine oxidation appears to be one of the mechanisms involved in the increase of the amino acid pool in the hepatopancreas.
Schein
Vanessa
V
Department of Physiology, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, 90050-170 Porto Alegre, RS, Brazil.
Fernandes Chittó
Ana Lúcia
AL
Etges
Rodrigo
R
Kucharski
Luiz Carlos
LC
van Wormhoudt
Alain
A
Da Silva
Roselis S M
RS
D000409:Alanine / Q000737:chemistry / Q000378:metabolism; D000596:Amino Acids / Q000737:chemistry* / Q000378:metabolism*; D000818:Animals; D003386:Brachyura / Q000737:chemistry / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism; D002247:Carbon Isotopes; D043143:Hepatopancreas / Q000737:chemistry / Q000378:metabolism; D007568:Jaw / Q000737:chemistry / Q000378:metabolism; D009132:Muscles / Q000737:chemistry / Q000378:metabolism; D009997:Osmotic Pressure; D010084:Oxidation-Reduction; D013997:Time Factors; D015091:beta-Alanine / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism
D000596:Amino Acids; D002247:Carbon Isotopes; D015091:beta-Alanine; D002245:Carbon Dioxide; C012924:2,2-dimethyl-beta-alanine; D000409:Alanine