POSSIBLE ROLE OF THE CHOROID-PLEXUS IN THE SUPPLY OF BRAIN-TISSUE WITH POLYUNSATURATED FATTY-ACIDS

Delta-6 desaturase was measured in rat brain microvessels and choroid plexus by incubation in the presence of radioactive linoleic acid. Und er our conditions, in 21-day-old animals, delta-6 desaturase was not d etected in brain microvessels. In contrast, it was present in choroid plexus (about 21 pmol/min per mg protein). In comparison, the activity in brain was much lower (about 1 pmol/min per mg protein) and higher in liver (about 55 pmol/min per mg protein). Interestingly, during dev elopment the activity in choroid plexus peaked at day 6 after birth an d declined slightly thereafter. The pattern of incorporation of linole ic acid radioactivity was not the same in choroid plexus and microvess els. These results show that delta-6 desaturase was not detected in br ain microvessels but was present in choroid plexus. (C) 1997 Elsevier Science Ireland Ltd.