supply as a rate-limiting factor has been observed in the glucuronidation of 7-

hydroxycoumarin (Conway et al., 1988) and acetaminophen given together with retinol

(which depletes UDPGA stores) (Bray and Rosengren 2001).

Table 6-1. UDPGA concentrations (uM) in liver and intestine of various species
Species Liver Small intestine
 Reference

Human 279, 301 f 119 19.3 f 4.5 Cappiello et al., 1991, 2000

Human fetus 59.4 f 11.3 Cappiello et al., 2000

Rat 200-500 121 f 5 Hjelle et al., 1985, Goon
 70 crypt cells and Klaassen 1992,
 200 villus cells Yamamura et al., 2000,
 Dills et al., 1987D, Pang et
 al., 1981, Hjelle 1986,
 Zhivkov et al., 1975 D,
 Dubey and Singh 1988
Mouse 201 f 17.6 Bray and Rosengren 2001

Guinea-pig 413 f 3 322 580 Zhivkov et al., 1975 D,
 79 f 6 stomach Singh et al., 1986
 36 f 3 colon
Pig 292 f 24 Zhivkov et al., 1975 D
Cat 153
Rabbit 182 f 20
Chicken 511 6 Ibid
Turkey 124 f 26
Pigeon 78 f 13
Frog 81 111 Ibid
Newt 73 f 5
Trout 116 &8 Ibid
Carp 21f 3
D refers to a direct method of UDPGA measurement. All other references relied on
indirect methods of UDPGA determination (see discussion).

 Biphasic UDPGA kinetics have been demonstrated for 1-naphthol, morphine, 4-

methylumbelliferone, and 3 -hydroxybenzo[a]pyrene (Miners et al., 1988a,b; Tsoutsikos

et al., 2004; Chapter 3). Whether this was due to the presence of multiple enzymes or an