Lipid interchange between lipoproteins and hepatopancreas in arachnids

LAINO A.; GARCIA F.; CUNNINGHAM M.; HERAS H.

Mar del Plata, Buenos Aires

Congreso; XLIII Reunión Anual de la Sociedad Argentina de Investigaciones en Bioquímica y Biología Molecular; 2007

Three lipoprotein HDL-l, HDL-2 and VHDL were isolated from hemolymph of the arachnid Polybetes pythagoricus. Phospholipids, free fatty acids and triglycerides were the major lipids. Our aim was to the study the lipid uptake through lipoproteins and their interchange with hepatopancreas (HP – similar to liver in mammals). HP and hemolymph (HL) were labeled by ammonium palmitate C 14 injection. At different times of incubation in vivo, HP were dissected, HL extracted and lipoproteins isolated by ultracentrifugation. Labeling was counted in a liquid scintillation counter. Lipids were separated by TLC, and radioactivity was quantified using a scanner. In HL labeling was incorporated mainly in HDL-l and VHDL. Throughout time. labeling proportion in HL decreased whereas it increased in HP. At short times, most labeling was found in free fatty acids, but at longer times of incubation the incorporation was observed in phospholipids as well as in triacylglycerols which were mainly present in HP. In conclusion. hemolymphatic lipoproteins of P. pythagoricus are able to incorporate palmitic acid and to transfer it to tissues. The synthesis of phospholipids and acylglycerides was demonstrated, consequently HP would be an important organ for the lipid metabolism.