Characterization of the UDP-glucuronosyltransferase isoenzyme expressed in rat ovary and its regulation by gonadotropins

Abstract

Earlier studies have demonstrated that phenol UDP-glucuronosyltransferase (UGT) activity is up-regulated by pregnant mare's serum gonadotropin (PMSG) in rat ovary, but not liver. This phenomenon was investigated in more detail in the present study. Ovaries and livers of immature rats, rats synchronized with respect to their preovulatory and corpus luteal phases by treatment with PMSG, and mature rats hyperstimulated with PMSG were compared. Under all of these conditions, only one immunoreactive band of UGT, shown to be phenol UGT, was detected in the rat ovary. The effects of oestradiol, progesterone and/or human chorionic gonadotropin (hCG) on the level of phenol UGT in immature rat ovary were also examined. Partial up-regulation was caused by progesterone or oestradiol, together with hCG, whereas progesterone or oestradiol alone had no up-regulating effect. Follicle-stimulating hormone also seemed to be required for the up-regulation in ovaries enriched in corpus luteum. The present findings demonstrate that progesterone is involved in the regulation of phenol UGT in rat ovary by gonadotropins. Regulation by both progesterone and oestradiol was dependent on induction of ovulation and steroidogenesis by luteinizing hormone.

The impact of bisphenol S on bovine granulosa and theca cells

“…There were no significant differences between any groups (p > .05) unconjugated form (Le Fol et al, 2015). Levels of glucuronosyltransferase enzymes have been reported to be upregulated in response to gonadotropins in rats (Becedas, Lundgren, & Pierre, 1998;Magnanti et al, 2000). Therefore, further investigation into whether FSH alters the ratio of conjugated/unconjugated BPS in bovine granulosa cells is warranted.…”

“…BPS is converted into glucuronide‐ and sulphate‐conjugated forms by a number of zebrafish and human cell lines, and these conjugated forms have significantly lower oestrogenic activity than the unconjugated form (Le Fol et al., ). Levels of glucuronosyltransferase enzymes have been reported to be upregulated in response to gonadotropins in rats (Becedas, Lundgren, & Pierre, ; Magnanti et al., ). Therefore, further investigation into whether FSH alters the ratio of conjugated/unconjugated BPS in bovine granulosa cells is warranted.…”

Regulation of uridine diphosphate-glucuronosyltransferase 2B15 expression during ovulation in the rat

“…The UGT enzymes are categorized into two major families: UGT1, members of which catalyze the glucuronidation of phenolic compounds and bilirubin; and UGT2, which consists of steroid-metabolizing UGTs [3]. The UGT2 family is further divided into two subfamilies: UGT2A, members of which inactivate odorant molecules; and UGT2B, members of which catalyze the glucuronidation of steroids and bile acids [2].…”