Effects of hypo- or hyperosmotic stress on lipid synthesis and gluconeogenic activity in tissues of the crab Neohelice granulata

• Published in: Comparative biochemistry and physiology. Part A, Molecular & integrative physiology Molecular & integrative physiology, 2011-04, Vol.158 (4), p.400-405
• Main Authors: Martins, Tiago L., Chittó, Ana Lúcia F., Rossetti, Camila L., Brondani, Camila K., Kucharski, Luiz Carlos, Da Silva, Roselis S.M.
• Format: Article
• Language: English
• Subjects: amino acids; Animals; Brachyura - enzymology; Carboxy-Lyases - metabolism; crabs; Crustacean; Decapoda; fructose-bisphosphatase; Fructose-Bisphosphatase - metabolism; gills; Gills - enzymology; Gluconeogenesis; glucose 6-phosphate; Glucose-6-Phosphatase - metabolism; hepatopancreas; Hepatopancreas - enzymology; Lipid synthesis; Lipids - biosynthesis; lipogenesis; Male; muscles; Muscles - enzymology; Osmotic Pressure; Osmotic stress; PEPCK
• ISSN: 1095-6433; 1531-4332
• DOI: 10.1016/j.cbpa.2010.11.023

The present study assesses the effects of osmotic stress on phosphoenolpyruvate carboxykinase (PEPCK), fructose 1,6-bisphosphatase (FBPase) and glucose 6-phosphatase (G6Pase) activities and 14C-total lipid synthesis from 14C-glycine in the anterior and posterior gills, jaw muscle, and hepatopancreas of Neohelice granulata. In posterior gills, 24-h exposure to hyperosmotic stress increased PEPCK, FBPase and G6Pase activities. Increase in 14C-lipid synthesis was associated to the decrease in PEPCK activity after 72-h exposure to hyperosmotic stress. Hypo-osmotic stress decreased PEPCK and G6Pase activities in posterior gills; however, 14C-lipids increased after 72-h exposure to stress. In anterior gills, decreases in the G6Pase activity after 72-h of hyperosmotic stress and in 14C-lipogenesis after 144-h were observed, while PEPCK activity increased after 144h. Exposure to hypo-osmotic stress increased 14C-lipid synthesis and PEPCK activity in anterior gills. Muscle G6Pase activity increased after 72-h exposure to hypo-osmotic stress; however, no significant change was observed in the lipogenesis. PEPCK decreased in muscle after 144-h exposure to hyperosmotic, coinciding with increased 14C-lipid synthesis. In the hepatopancreas, a decrease in the 14C-lipogenesis occurred after 24-h exposure to hyperosmotic stress, accompanied by increase in 14C-lipid synthesis. Additionally, PEPCK activity returned to control levels. The hepatopancreatic lipogenesis from amino acids was not involved in the metabolic adjustment during hypo-osmotic stress. However, gluconeogenesis is one of the pathways involved in the adjustment of the intracellular concentration of nitrogenated compounds.