Drug Metabolism in Drug Design and Development Basic Concepts and Practice

.UGT1various forms catalyze conjugation of planar phenols, bulky

phenols, amines, tertiary amines, and bilirubin. (Nine active human

forms now cloned are expressed, i.e., 1A1, 1A3–1A10).

.UGT2Aolfactory (nasal) UGTs.

.UGT2Bxenobiotics, steroids and bile acids (4 human active enzymes,

i.e., 2B4, 2B7, 2B10, 2B15, 2B17).

COOH

HO

Etianic acid (C20a,b )

COOH

HO

HO

COOH

Lithocholic acid (3a-OH)

cis ring A/B fusion

HO

COOH

Hyodeoxycholic acid (3a, 6 a -OH)

OH

OH

O

Testosterone (17b-OH)

OH

HO

Androsterone (3a-OH,5a)

H

OH

HO

Estradiol (17 b-OH)

OH

HO

OH

Estriol (16a,-17b-OH)

O

HO Estrone

(3a-OH,5b)

FIGURE 3.4 Structures of endogenous compounds involved in glucuronidation: bile
acids, lithocholic acid (LA) and hyodeoxycholic acid (HDCA); short chain bile acids,
etianic acid and isoetianic acid, steroid hormones, androsterone, testosterone, estrone,
estradiol, estriol.

UDP-GLUCURONOSYLTRANSFERASES 41