The effect of fatty acids on the vulnerability of lymphocytes to cortisol.

We have shown previously that cortisol-sensitive lymphocytes (thymocytes) have a much lower capacity than cortisol-resistant cells to catabolize cortisol and that linoleic acid inhibits the catabolism of cortisol by lymphocytes and modulates the sensitivity of lymphocytes to cortisol. In the present study, we attempted to see whether other fatty acids are inhibitory and if inhibition of cortisol catabolism by lymphocytes indicates a change in resistance of the cells to cortisol. Measuring the effect of fatty acids on cortisol catabolism by lymphocytes indicated that the polyunsaturated fatty acids, linoleate, arachidonate, and eicosapentaenoic, inhibit cortisol catabolism by lymphocytes. Using prostaglandin PGE2 and indomethacin as a blocker of prostaglandin formation, we observed that the effect of the polyunsaturated fatty acids was not due to the formation of prostaglandins. Examining the effect of fatty acids on the vulnerability of lymphocytes to cortisol, we noted that saturated fatty acids had no significant effect, whereas the aforementioned polyunsaturated fatty acids make lymphocytes more sensitive to cortisol.