In vitro activity of the fatty acyl desaturases of human cancerous and noncancerous tissues.

The microsomal desaturase activity of human cancerous and noncancerous tissues was measured in vitro using 1-14C, -11, 14-eicosadienoic and 1-14C-oliec acids as substrates. Tissues used were a case of ovarian cancer, a urinary bladder cancer, a rectal cancer, and a non-specific colonic ulcer with appropriately normal tissues. When 11, 14-20:2 was used as substrate, radioactive tetraene and triene were produced. The tetraene was identified by radio gas chromatography as arachidonic acid (5, 8, 11, 14-20:4), and the triene had a retention time of 5, 11, 14-20:3. Thus, the possibility arises that a delta8 desaturase was involved. In the delta6 desaturase, with the urinary bladder cancerous tissue, the desaturase activity appeared to be decreased in comparison to neighboring tissue, whereas with the colonic cancer tissue, the desaturase appeared to be relatively increased, though the number of samples was inadequate for confidence.