Effect of prostacyclin on the mixed function microsomal oxigenase system in the rat liver.

The microsomal fraction of the liver was studied for protein and cytochrome P450 contents as well as for aminopyrine-N-demethylase and aniline-hydroxylase activity and for its BIC spectrum under the effect of PG-I2 treatment. A significant increase was found in the cytochrome P450 content after short term treatment, while continuation of PG-I2 administration caused a significant and long lasting decrease of cytochrome P450. After prolonged application of PG-I2 the aniline-hydroxylase content decreased significantly, while the aminopyrine-N-demethylase enzyme showed no change. The BIC spectrum after 80 days PG-I2 treatment significantly decreased in the 431-432 nm region, corresponding to the decrease of cytochrome P450. Long term PG-I2 application caused no detectable ultrastructural changes in the liver.