Competitive incorporation of arachidonic acid analogs by cultured rat keratinocytes.
Arachidonic acid (20:4 n-6) and its metabolic products, such as prostaglandins and leukotrienes, have been known to be associated with skin inflammatory reactions. However, the mechanism of the competitive incorporation of 20:4 n-6 into keratinocytes among polyunsaturated fatty acids (PUFAs) remains uncertain. To investigate the relationship between the molecular structure of PUFAs and the rate of incorporation of PUFAs into cells, a fetal rat skin keratinocyte (FRSK) cell line was used. The cells were incubated for 24 h with any two of the following arachidonic acid analogs: mead acid (20:3 n-9), dihomo-gamma-linolenic acid (20:3 n-6), 11,14,17-cis-eicosatrienoic acid (20:3 n-3), arachidonic acid (20:4 n-6), eicosapentaenoic acid (20:5 n-3) and 5,8,11,14-cis-nonadecatetraenoic acid (19:4 n-5), at the ratio of 1:0, 0.5:0.5, or 0:1; and their incorporation into lipid was measured by capillary gas-liquid chromatography. The experiments indicated that 20:3 n-6 was preferentially incorporated into phospholipids of FRSK rather than 20:3 n-9 or 20:3 n-3, and 19:4 n-5 as well as 20:4 n-6 was preferentially incorporated into total cellular lipid and phospholipids rather than 20:3 n-9 or 20:5 n-3. When two PUFAs were added simultaneously to the medium, 19:4 n-5 most effectively reduced the competitive incorporation of 20:4 n-6 into phospholipids. These results suggest that keratinocytes discriminate 20:4 n-6 from other arachidonic acid analogs by its double bond positions from the carboxyl group.
Nakano
N
N
Department of Food Science and Nutrition, Faculty of Agriculture, Kinki University, Nara, Japan.
Shirasaka
N
N
Kurihara
M
M
Takamatsu
M
M
Murakami
T
T
Yoshizumi
H
H
Tsuboi
R
R
Ogawa
H
H
D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism; D001095:Arachidonic Acids / Q000737:chemistry / Q000378:metabolism*; D001667:Binding, Competitive; D002460:Cell Line; D002849:Chromatography, Gas; D005231:Fatty Acids, Unsaturated / Q000737:chemistry / Q000378:metabolism*; D015603:Keratinocytes / Q000378:metabolism*; D010743:Phospholipids / Q000096:biosynthesis*; D051381:Rats
D001095:Arachidonic Acids; D005231:Fatty Acids, Unsaturated; D010743:Phospholipids; D016718:Arachidonic Acid