Induction of 16alpha-hydroxylase in cultured human lymphocytes

Lymphocytes grown for 72 hr in the presence of mitogenic agents exhibited a nine-fold increase in 16alpha-hydroxylase activity over a 24-hr period following the addition of 17beta-estradiol as an inducing agent. The major metabolite of 17beta-estradiol produced by induced lymphocytes showed a chromatographic mobility indistinguishable from that of estriol. Enzymatic activity increased linearly with cell numbers, was inhibited by CO, and exhibited no induced increase in the presence of cycloheximide. A population survey indicated about 68% of a randomly selected Caucasian group to be essentially uninducible for 16alpha-hydroxylase.