Osmotic regulation of lipid metabolism in renal epithelial cells.

WEBER, KAREN; CASALI, CECILIA IRENE; MOREL GOMEZ, EMANUEL; FAGGIONATO, DANIELA; . FERNÁNDEZ TOME, MARIA DEL CARMEN

Potrero de los Funes, San Luis, Argentina

Congreso; XLVII Reunión de la Sociedad Argentina de Investigaciones Bioquímicas y Biología Molecular- SAIB; 2011

Due to the urine concentration mechanism, the renal papillary interstitium has the highest osmolarity of the body. To survive and work in such harmful environment, renal cells have protectivemechanisms. We showed that papillary cells possess the highest phospholipid synthesis and turnover of the kidney, which contribute to preserve membrane homeostasis and cell viability. We also showed that renal phospholipid metabolism is regulated by osmolarity. Considering that phospholipid synthesis require an adequate supply of fatty acids,in this work we characterized the relationship betweenphospholipids (PL) and triacylglycerol (TG) in renal cells.The levels of PL and TG were determined in the different zones of the kidney and in cultures of the renal cell line MDCK grown during 24, 48, 72 and 96 h in media with osmolalities from 298 to 570 mOsm/kgH2O.Renal cortex(isosmolar conditions) showed the highest PL content but the lowest TG content and PL synthesis. In opposite, papillary cells showed the lowest PL content but the highest TG content and PL synthesis. In MDCK cells, we found that hyperosmolarity significantly increases the content of PL and TG. Such increase is dependent on the time of incubation and the osmolarity of the medium. These results demonstrate the relationship between renal PL synthesis and TG content and the role of environmental osmolarity as a distinctive regulatory factor of renal lipid metabolism.