The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids.

[7] CYP7B was discovered by Stapleton[8] in a screen for transcripts expressed differentially in rat hippocampus versus the remainder of the brain.

The encoded polypeptide, initially designated hct-1 (hippocampus transcript 1), had significant homology with CYP7A1.

Expression of the recombinant protein demonstrated 7alpha-hydroxylation activity for steroids (DHEA, pregnenolone) and oxysterols including 25-hydroxycholesterol and 27-hydroxycholesterol,[9][10][11] confirmed by knockout in mouse that abolished oxysterol hydroxylation in liver[12] and brain and steroid hydroxylation in multiple tissues.

[13] Reporter tagging of the Cyp7b1 gene demonstrated that the enzyme is widely expressed, particularly strongly in brain, liver, kidney, heart, and spleen.