Effect of indomethacin treatment on prostaglandin excretion and tissue phospholipid fatty acid composition in rats bearing mammotropic pituitary tumor, MtT-F4.

The hypothesis that hormonal changes induced by the mammotropic pituitary tumor, MtT-F4, might accelerate the conversion of n-6 fatty acids to prostaglandins, resulting in a partial depletion of n-6 fatty acids was examined. In tumor-bearing rats, the administration of indomethacin induced a 50% reduction of the urinary prostaglandin levels, but exerted no significant effect on the fatty acid composition of the tissue phospholipids. It is concluded that the observed depletion of n-6 fatty acids in tumor-bearing rats is not caused by an increased production of prostaglandins.