Multiplicity of in vitro glucuronidation of 2-hydroxyestriol.
In vitro glucuronidation of 2-hydroxyestriol has been investigated by means of HPLC with dual-electrode coulometric detection. When incubated with rat or dog liver microsomal preparation in the presence of UDPGA, 2-hydroxyestriol was transformed into the 2-glucuronide together with a small amount of 16- and/or 17-glucuronides. In contrast, incubation of 2-hydroxyestriol with guinea-pig liver microsomal preparation yielded the 3-glucuronide and a trace amount of the 2-glucuronide, but no ring D glucuronides. Upon pretreatment with 3-methylcholanthrene male rat liver exhibited a marked increase in both 2- and 3-glucuronidation activities, whereas female rat liver showed an elevation only in 2-glucuronidation. On the other hand, in male and female rats pretreatment with phenobarbital caused a relatively small increase in the glucuronidation activity of the liver. In the male guinea-pig, glucuronidation was not affected by pretreatment with either of the two compounds. The present result demonstrates the multiplicity of hepatic 2-hydroxyestriol UDP-glucuronyl-transferase in the rat, guinea-pig and dog.
Ohkubo
T
T
Pharmaceutical Institute, Tohoku University, Sendai, Japan.
Takahashi
A
A
Nambara
T
T
D000818:Animals; D004285:Dogs; D004964:Estriol / Q000378:metabolism* / Q000031:analogs & derivatives; D002393:Estrogens, Catechol / Q000378:metabolism*; D004966:Estrogens, Conjugated (USP) / Q000378:metabolism*; D005260:Female; D005965:Glucuronates / Q000378:metabolism*; D006168:Guinea Pigs; D007536:Isomerism; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D014535:Uridine Diphosphate Glucuronic Acid / Q000378:metabolism*
D002393:Estrogens, Catechol; D004966:Estrogens, Conjugated (USP); D005965:Glucuronates; C008012:2-hydroxyestriol; D014535:Uridine Diphosphate Glucuronic Acid; D004964:Estriol