title: Arachidonic acid pools of rat kidney cell nuclei.
abstract: We have assessed that nuclear lipids from rat kidney cells are not only membrane components, but they are also found within the nucleus. The most abundant nuclear and endonuclear lipids have a high proportion of unsaturated fatty acids (n-6 series: arachidonic > linoleic), mainly esterified to PtdCho. Nuclear most abundant molecular species are 16:0-20:4, 16:0-18:2, 18:0-20:4, 18:0-18:2, and 16:0-18:1. Arachidonic acid is esterified at the sn-2 position of PtdCho: 16:0-20:4(25%), 18:0-20:4(15%), 18:2-20:4(3%), 18:1-20:4(2%). Exogenous [1-(14)C]20:4n-6-CoA is esterified in vitro in GP (glycerophospholipids) > > TAG and DAG. Five PtdCho molecular species were labeled: 16:0-20:4, 18:0-20:4, 18:1-20:4, 18:2-20:4, and 20:4-20:4. In conclusion, these results demonstrated that: (1) there is an important lipid pool within kidney cell nuclei; (2) main nuclear and endonuclear lipid pools were PtdCho molecular species which contained a high proportion of unsaturated fatty acids (20:4n-6 and 18:2n-6) esterified at sn-2 position and 16:0 esterified at sn-1 position; (3) kidney cell nuclei also contained the necessary enzymes to esterify exogenous 20:4n-6-CoA to glycerolipids and to GP; (4) exogenous 20:4n-6-CoA was esterified in five PtdCho molecular species with 20:4n-6 at the sn-2 position, although the most actively synthesized PtdCho contained 20:4n-6 at both the sn-1 and sn-2 positions of the molecule; (5) we can infer that by a remodeling process, the unsaturated fatty acids at the sn-1 position of PtdCho molecular species could be replaced by 16:0 and 18:0, and thus PtdCho would achieve the physiological profile characteristic of the organ.
authors.affiliation: Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP, CCT-La Plata, CONICET-UNLP), Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Calles 60 y 120, 1900, La Plata, Argentina.
authors.forename: Sabina M
authors.initials: SM
authors.lastname: Maté
authors.forename: Juan P
authors.initials: JP
authors.lastname: Layerenza
authors.forename: Ana
authors.initials: A
authors.lastname: Ves-Losada
mesh_terms: D000818:Animals; D016718:Arachidonic Acid; D002467:Cell Nucleus / Q000737:chemistry*; D005231:Fatty Acids, Unsaturated / Q000032:analysis*; D007668:Kidney / Q000648:ultrastructure*; D008055:Lipids / Q000032:analysis*; D010713:Phosphatidylcholines / Q000032:analysis; D051381:Rats
chemical_list: D005231:Fatty Acids, Unsaturated; D008055:Lipids; D010713:Phosphatidylcholines; D016718:Arachidonic Acid