16a-Hydroxyestrone, Urine Creatinine Ratio Unit Converter

16α-Hydroxyestrone (16α-OHE1) is a metabolite of estrone, one of the body's three main estrogens. When the body breaks down estrone, it follows one of three major pathways: 2-hydroxylation, 4-hydroxylation, or 16α-hydroxylation. This marker measures the product of the 16α-hydroxylation pathway.

Unlike other estrogen metabolites, 16α-OHE1 binds covalently (permanently) to the estrogen receptor. Once bound, the receptor does not shut off normally, resulting in prolonged estrogenic signaling. This makes 16α-OHE1 a relatively potent estrogen metabolite.

This test measures 16α-OHE1 in urine, normalized to creatinine to account for differences in urine concentration. It is often evaluated alongside 2-hydroxyestrone and other estrogen metabolites as part of a comprehensive estrogen metabolism panel.

Produced primarily in the liver through CYP3A4 and CYP3A5 enzymes that hydroxylate estrone at the 16α position. Smaller amounts are produced in adipose tissue, breast tissue, and the intestinal wall.